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Metallurgia Italiana

International Journal of the Italian Association for Metallurgy

n.07/08 Luglio-Agosto 2026 Organo ufficiale dell’Associazione Italiana di Metallurgia. Rivista fondata nel 1909

La Metallurgia Italiana International Journal of the Italian Association for Metallurgy Organo ufficiale dell’Associazione Italiana di Metallurgia. House organ of AIM Italian Association for Metallurgy. Rivista fondata nel 1909

Direttore responsabile/Chief editor: Mario Cusolito Direttore vicario/Deputy director: Gianangelo Camona Comitato scientifico/Editorial panel: Marco Actis Grande, Ettore Anelli, Silvia Barella, Enrico Baroni, Paola Bassani, Shahab Bazri, Christian Bernhard, Massimiliano Bestetti, Wolfgang Bleck, Franco Bonollo, Irene Calliari, Riccardo Carli, Mariano Enrique Castrodeza, Emanuela Cerri, Vlatislav Deev, Andrea Di Schino, Donato Firrao, Piero Frittella, Berndt Kleimt, Carlo Mapelli, Susanne Michelic, Roberto Montanari, Marco Ormellese, Mariapia Pedeferri, Massimo Pellizzari, Annalisa Pola, Ulrich Prahl, Barbara Previtali, Dario Ripamonti Segreteria di redazione/Editorial secretary: Flynn Russo Comitato di redazione/Editorial committee: Federica Bassani, Gianangelo Camona, Mario Cusolito, Carlo Mapelli, Federico Mazzolari, Flynn Russo Direzione e redazione/Editorial and executive office: AIM - Via F. Turati 8 - 20121 Milano tel. 02 76 02 11 32 - fax 02 76 02 05 51 met@aimnet.it - www.aimnet.it Reg. Trib. Milano n. 499 del 18/9/1948. Sped. in abb. Post. - D.L.353/2003 (conv. L. 27/02/2004 n. 46) art. 1, comma 1, DCB UD Immagine in copertina: Shutterstock

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Metallurgia Italiana

International Journal of the Italian Association for Metallurgy

n.07/08 Luglio-Agosto 2026 Organo ufficiale dell’Associazione Italiana di Metallurgia. Rivista fondata nel 1909

Editoriale / Editorial

a cura di Bernd Kleimt, VDEh‑Betriebsforschungsinstitut – BFI ......................................................................... pag.05

Memorie scientifiche / Scientific papers Decarbonizzazione/ CO2 Mitigation

Heat transfer mechanisms in Electric Smelter Furnaces for ironmaking

U. Kudaru, G. Brooks, S. Sabah, M.A. Rhamdhani, K. Owusu, B. Kumar, C. Chen, A. Guiraud .......................... pag.08

n.07/08 Luglio-Agosto 2026 Anno 117 - ISSN 0026-0843

Effect of hydrogen oxyfuel combustion on oxide scale descalability by thermal shock for low-carbon steels

S. Airaksinen, K. Siltala, J. Haapakangas, A. Heikkilä, Q. Shu .............................................................................. pag.13

Attualità Industriale / Industry News Development and application of a particle conversion model for the utilization of biochar in an electric arc furnace to substitute fossil coal

indice

T. Griessacher, M. Blank, K. Supancic, C. Schlögl, I. Obernberger ............................................................................. pag.24

Circular carbon and electrified heat: carbon neutral syngas heated by Paul Wurth Tempra to reduce blast furnace CO₂ emissions

L. Micheletti, C. Castagnola, A. Olcese, M. Venturini ..................................................................................................... pag.36

Ecological assessment of the use of hydrochar in EAF operation based on an LCA approach C. Gondorf, F. Kaiser, T. Echterhof ..................................................................................................................................... pag.44

Renewable Carbon Integration in HIsarna Ironmaking Process

N. Madhavan, N. Dogan, Y. Yang, K. Meijer, J.L.T. Hage ................................................................................................ pag.54

Thermodynamics and kinetic modelling of flash reduction ironmaking

S. Sabah, A.R. Rhamdani, B. Mokhtarani, B.A. Nuraeni, G. Brooks, M.A. Rhamdhani, M. Boot-Handford, S. van

Dorp ........................................................................................................................................................................................... pag.57

Atti e notizie / AIM news

Il futuro della metallurgia non solo in aula: EAC Summer School ..................................... pag.64 Eventi AIM / AIM events ......................................................................................................................................... pag.67 Normativa / Standards ............................................................................................................................................ pag.70

Convegno Nazionale AIM

il futuro tra ricerca e innovazione

Brescia 9-11 settembre 2026 organizzato da

iscrizioni e programma su

www.aimnet.it/nazionaleaim partners enti patrocininatori

UN SA sponsor

（LOGO46）

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�946 2026

media partners ® an ipcm® magazine

“

"CO₂ mitigation emerged as a central theme throughout the EEC and EMECR conference. The reduction of greenhouse gas emissions was a recurring focus of the presented research and industrial case studies. This wi‑ despread attention reflects the urgency of achieving ambitious climate targets while maintai‑ ning the competitiveness and resilience of steel production in Europe.”

editoriale - editorial

Bernd Kleimt VDEh‑Betriebsfor‑ schungsinstitut - BFI

FROM VISION TO INDUSTRIAL REALITY: ADVANCING LOW-CARBON ELECTRIC STEELMAKING The European Electric Steelmaking Conference has long

egies. Collectively, these developments underline the

served as a benchmark for technological progress in Elec-

pivotal role of EAF-based steelmaking in supporting the

tric Arc Furnace (EAF) steelmaking. Reflecting on my first

transition toward a climate-neutral European steel sector.

participation in this conference series in Paris in 1995, it is

A particularly valuable aspect of the event was its close

striking to observe the magnitude of the transformation

connection with the 5th International Conference on En-

that has taken place over the past three decades. Many of

ergy and Material Efficiency and CO₂

the concepts that are now at the centre of scientific and

Steel Industry, which took place in parallel. The synergy

industrial discussion—including decarbonization through

between the two conferences fostered an interdisciplin-

biogenic carbon carriers, use of hydrogen-reduced alter-

ary exchange of knowledge and experience, highlight-

native iron sources, and artificial intelligence-based pro-

ing the strong interdependence between technological

cess control—were, at that time, largely visionary ideas.

innovation, resource efficiency, and environmental per-

Today, they are becoming key enablers of a more sustain-

formance. Together, the conferences provided a compre-

able and competitive steel industry.

hensive platform for addressing the challenges and op-

The 14th European Electric Steelmaking Conference, held

portunities associated with the ongoing transformation of

in Milan, clearly demonstrated the remarkable pace of

the steel industry.

innovation currently shaping EAF technology. The con-

Notably, CO₂ mitigation emerged as a central theme

tributions presented at the conference reflected substan-

throughout both events. The reduction of greenhouse

tial advances across a broad range of research and devel-

gas emissions was a recurring focus of the presented re-

opment areas, from raw material utilization and process

search and industrial case studies. This widespread atten-

optimization to digitalization and carbon mitigation strat-

tion reflects the urgency of achieving ambitious climate

La Metallurgia Italiana - July-August 2026

Reduction in the

pagina 5

editoriale - editorial methodologies (Gondorf et al.). Furthermore, the

ience of steel production in Europe.

practical implementation of biochar in Electric Arc Fur-

In recognition of this overarching theme, the present is-

naces is discussed by Griessacher et al.

sue of La Metallurgia Italiana is dedicated to recent de-

Alternative ironmaking routes are also highlighted. Sabah

dell’Associazione Italiana

targets while maintaining the competitiveness and resil-

the breadth of current research and industrial activities

iron (DRI) from iron ore fines. Complementing these

aimed at transforming steel production into a more sus-

technological developments, several contributions focus

tainable process.

on supporting measures for process optimization and op-

Rivista fondata nel 1909

promising pathway for the production of direct reduced

di Metallurgia.

steelmaking. The contributions assembled here reflect

Organo ufficiale

et al. present the flash reduction ironmaking process as a

n. 6 giugno 2020

velopments and future perspectives in CO₂ mitigation in

erational excellence.

abler of low-carbon metallurgy: Airaksinen et al. examine

Together, the articles collected in this issue provide valu-

the use of hydrogen in reheating furnaces. Advancing our

able insights into the technologies, methodologies, and

understanding of process efficiency, Kudara et al. pres-

strategies that are shaping the transition toward low-car-

ent a modelling approach for heat transfer mechanisms in

bon steelmaking. We hope that they will foster further

Electric Smelting Furnaces.

discussion, strengthen collaboration between academia

International Journal of the Italian Association for Metallurgy

Several papers explore the role of hydrogen as a key en-

A particular focus of this issue is placed on the growing and industry, and inspire continued innovation as we col-

importance of biochar as a renewable carbon source. The lectively advance toward a more sustainable future for dling

and

Metallurgia

contributions address critical aspects ranging from han- steel production. safety

considerations

environmental

Italiana

performance assessed through Life Cycle Assessments

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 6

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Memorie scientifiche - Decarbonizzazione

DOI 10.36146/2026_0708_08

Heat transfer mechanisms in Electric Smelter Furnaces for ironmaking U. Kudaru, G. Brooks, S. Sabah, M.A. Rhamdhani, K. Owusu, B. Kumar, C. Chen, A. Guiraud Electric Smelter Furnaces (ESF) are critical for the transition toward sustainable ironmaking, requiring precise control of plasma arc heat transfer to optimize efficiency. This study investigates the axial distribution of volumetric heat sources specifically Joule heating, radiation, and the Thompson effect within a DC brush arc configuration. Results demonstrate that extreme current density at the cathode tip drives intense Joule heating, creating a localized thermal hot spot at the emission boundary. As the arc expands, direct electrical heating rapidly decays, leaving radiation to govern energy transport through the plasma column toward the slag bath. Furthermore, while electron enthalpy transport by the Thompson effect is an order of magnitude smaller than radiation, and this is concentrated near the base of electrode, and it is essential for understanding the central heat flux as it relates especially to heat transfer in the plasma medium. By highly localizing energy delivery to the smelting zone, the brush arc effectively shields the surrounding furnace structure from excessive radiative loads. Future work will couple these arc heat transfer mechanisms with convective bath models to further optimize ESF thermal efficiency.

KEYWORDS: ELECTRIC SMELTER FURNACE (ESF); HEAT TRANSFER; OPEN SLAG BATH FURNACE (OSBF).

INTRODUCTION: THE EVOLUTION OF ELECTRIC SMELTING FURNACE The transition towards decarbonized steel industry has created the scope for the development of Electric Smelter Furnaces (ESF) as an alternative for making molten iron rather than the Blast Furnace (BF). When combined with Direct Reduced Iron (DRI), utilizing an ESF rather than a conventional, coke-based blast furnace has the potential to reduce CO₂ emission intensity by up to 85% (1). A sub-technology in this domain is the Open Slag Bath Furnace (OSBF). It takes the open-arc flexibility of an

Ujwal Kudaru, Geoffrey Brooks, Shabnam Sabah, M.A. Rhamdhani

Heavy Industry Low-carbon Transition Cooperative Research Centre

(HILT CRC); FPD (Fluid and Process Dynamics) Group, Department of

Mechanical and Product Design Engineering, Swinburne University of

EAF and combines it with the deep, resistive slag bath of

Technology, Hawthorn 3122 VIC, Australia

an SAFmaking it the primary furnace choice for smelt-

Kwaku Owusu, Banty Kumar, Chunlin Chen, Adrien Guiraud

ing fine, low-grade iron ore feeds (like H₂-DRI) into liquid hot metal.Unlike the SAF, where electrodes are fully

CSIRO Mineral Resources, Clayton, VIC 3169, Australia

submerged in a solid burden, the OSBF operates with an open slag bath, allowing for greater versatility in raw material chemistry and slag control (2). OSBF is operated in a brush arc where in the arc tends to be small and interacts with slag(3). In the “brush arc” configuration as shown in figure 1 the electrode tip is positioned such a way that the arc is partially submerged within the slag layer.

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 8

Scientific papers - Co2 Mitigation

Fig.1 - Schematic of Open Slag bath furnace. This partial submersion of the arc provides radiative

electric arc are mentioned in figure 2 to melt the new DRI

shielding and Heat dispersion into slag providing better

and save the walls and roof (4).

heat transfer and the heat transfer mechanisms from the

Fig.2 - Heat transfer mechanisms from Electric arc.

CFD MODELLING OF BRUSH ARC

heat transfer mechanisms. The model in figure 3 features

To understand the heat transfer and slag chemistry with-

a 10-millimeter-high electrode positioned within a fur-

in an Electric Smelter Furnace, a single-electrode Com-

nace chamber. The furnace walls are defined as adiabatic

putational Fluid Dynamics (CFD) model was developed

boundaries, ensuring that heat transfer remains confined

based on Magnetohydrodynamic (MHD) principles. The

within the system to allow focused analysis of arc gener-

components of the model are an electrode and a furnace

ated heat and the boundary conditions are mentioned in

chamber, with the investigation focusing on the funda-

table 2 thermophysical properties, including temperature

mental process of electric arc generation and its direct

dependency, defined by User defined Function proper-

impact on the surrounding environment, particularly on

ties.

La Metallurgia Italiana - July-August 2026

pagina 9

Memorie scientifiche - Decarbonizzazione

Fig.3 - 3D Geometry for modelling.

Tab.1 -Boundary Conditions for the model.

Area

A(x,y,z)

1000

—

3500

—

3500

J(x,y)

1000

—

1000

—

∂T/∂z = 0

Electrically, the bottom surface of the furnace represent-

This model solves the coupled conservation equations

ing the metal bed is maintained at zero electrical poten-

for mass, momentum, and energy across the steady state

tial, while the electrode is supplied with a positive electri-

electric arc from a single cathode spot on the electrode

cal potential and an associated electric flux at the cathode

interacting with plasma and slag. The total energy transfer

spot. This potential difference drives an electric current

from the brush arc is a composite of convection, radia-

that, as it attempts to bridge the inter-electrode gap of ap-

tion, and electron-mediated transport. The energy trans-

proximately 2.5 millimetres, ionizes the gaseous medium

fer equation used for modelling electric arcs is mentioned

to form and sustain the electric arc.

in equation 1(5) and all the parameters of heat transfer mechanisms are mentioned in the table 2.

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 10

Scientific papers - Co2 Mitigation Tab.2 - Heat transfer mechanisms equations in ESF(5).

Heat transfer

Equation

( (

(

)

= =

( +

)

In these equations, vg represent the velocity of gas in the z

transfer mechanisms are predicted. As illustrated in fig-

viscosity of the gas and slag respectively, and Jr and Jz are

the electrode base due to the localized concentration of

directions and ρ denotes density. The term μg and μs is the

the densities of current and in r and z directions. ∅a is the

work function of the anode and furthermore, σT and σ_e de-

note the thermal and electrical conductivities, while h and, Cp are enthalpy and specific heat capacity, Sr is the radia-

tion loss, kb is the Boltzmann constant, and e is the electron

charge and NEC is net emissive Coefficient (6).Due to the

complexity and the turbulence behaviour of arcs this paper only discusses about Joule heat, Radiation and Thompson

effect and their effect in the brush arcs with in carbon monoxide plasma.[PP1.1]

ure 4, the electron enthalpy flux and joule heat peaks near high current density and extreme plasma temperatures at

the cathode tip. Moving axially toward the slag bath, the

expansion of the plasma column leads to a gradual decay

in current density and thermal energy, resulting in a corresponding decrease in joule heat and electron enthalpy

transport. In the highly constricted cathode region, Joule heating dominates but decays exponentially as the arc ex-

pands. Conversely, radiative heat flux decays slowly, overtaking Joule heating in the expanded column to become the primary mechanism transferring heat to the slag bath.

RESULTS AND DISCUSSION

Axial distribution of heat sources from the cathode tip

of electrode to the slag bath is studied and different heat

Fig.4 - Comparison of Heat transfer mechanisms in plasma medium. La Metallurgia Italiana - July-August 2026

pagina 11

Memorie scientifiche - Decarbonizzazione CONCLUSION AND FUTURE WORKS

DECLARATION OF CONFLICTS OF INTERESTS

•

Joule Heating: In the brush arc mode current density

The Authors declare that there is no conflict of interest re-

(J) at the tip drives intense Joule heating (proportional

lated to this publication.

to •

•

) creating a massive thermal “hot spot” and

elevated heat flux at the cathode boundary.

ACKNOWLEDGEMENT

Radiation: Radiation proves to be one of the dominant

The work has been supported by Swinburne University

heat transfer mechanisms compared to joule and

and the Heavy Industry Low-carbon Transition Coope-

Thompson effect for distributing heat from the brush

rative Research Centre (HILT CRC), whose activities are

arc in an ESF.

funded by its industry, research, and government Part-

Thompson Effect: For shorter arc heights, enthalpy

ners along with the Australian Government’s Cooperative

transport by electron drift is an order of magnitude

Research Centre Programme, with project number HILT.

smaller than thermal radiation. This is primarily due to

RP1.014

the confined space for plasma gas circulation, which restricts overall heat transfer and localized Joule heating in this narrow gap FUTURE WORK In the future work we will be solving for convective heat transfer from the arc and study the heat transferred on to slag along with feed materials, roof and walls of the furnace and the validation will be done against industrial data from the partners involved in this project

REFERENCES [1] [2] [3] [4] [5] [6]

Gadd A, Tame N, Liu X, Dukino R. Prospects Pathways to decarbonisation episode seven The Electric Smelting Furnace. 2023; Steinberg WS, Pistorius PC. Control of open slag bath furnaces at Highveld Steel and Vanadium Ltd: Development of operator guidance tables. Ironmak Steelmak. 2009;36(7):500–4. Sabah S, Kudaru U, Brooks G, Rhamdhani MA, Owusu K, Kumar B. Application of Electric Smelting Furnace to Ironmaking. J Sustain Metall [Internet]. 2026;(0123456789). Available from: https://doi.org/10.1007/s40831-026-01459-2 A.Esterhuizen, P.Jonker. Tenova’s iBlue open bath furnace fundamental design decisions dor anDRI Smelter. Southern African Pyrometallurgy 2024. 2024. p. 57–67. Alexis J, Ramirez M, Trapaga G, Jönsson P. Modeling of a DC Electric Arc Furnace - heat transfer from the arc. ISIJ Int. 2000;40(11):1089– 97. Eckert ERG, Pfender E. Advances in Plasma Heat Transfer. Adv Heat Transf. 1967;4(C):229–316.

TORNA ALL'INDICE >

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 12

Scientific papers - Co2 Mitigation

DOI 10.36146/2026_0708_13

Effect of hydrogen oxyfuel combustion on oxide scale descalability by thermal shock for low‑carbon steels S. Airaksinen, K. Siltala, J. Haapakangas, A. Heikkilä, Q. Shu

Steel industry is in transition concerning heating methods due to requirement to reduce CO 2 emissions. Use of hydrogen as a fuel in combustion for heating makes the reheating furnace a possible method to reduce use of fossil fuels, and oxyfuel combustion increases efficiency of the heating process compared to air-fuel method. Oxide scale formation of two low carbon steels is studied under isothermal tests at 1200 °C for 2 hours with methane-air, methane-oxygen, and hydrogen-oxygen combustion atmospheres using free oxygen contents of 1% and 6%. Both steels contained silicon, but Steel A had higher amounts of manganese and Steel B had higher amounts of chromium and nickel. Descaling efficiency of oxidized samples is studied by thermal shock. Characterization for oxidized and descaled cross-sections of samples was performed by digital microscopy and field-emission scanning electron microscopy (FESEM). Results show that more nickel and chromium containing Steel B produces less oxide scale in all studied atmospheres, but its descaling efficiency by thermal shock is weaker compared to Steel A. Descaling efficiency decreases for both steels by changing heating method from methane-air to hydrogen-oxygen. Decrease of free oxygen content removes oxide scale from wider surface area. Steel B has more entanglement structure with deeper scale penetrations at oxide-steel interface, making its adherence higher. Thickness of interface scale for both steels after thermal shock decreases from methane-air method to hydrogen-oxygen method.

KEYWORDS: HYDROGEN COMBUSTION; OXYFUEL; REHEATING; LOW-CARBON STEEL; OXIDE SCALE; DESCALING. INTRODUCTION Hydrogen fuel combustion provides CO2-free heating methods for reheating furnaces compared to natural gas combustion, and efficiency of heating methods can be increased by changing combustion from air-fuel to oxyfuel. The complete combustion of the fuel gas is ensured by excess oxidant, providing free oxygen in the furnace gas atmosphere. Free oxygen content is kept low in industrial reheating furnace, typically around 2-5% [1-2], to prevent material loss due to excessive oxidation. Transition from natural gas combustion with air to hydrogen combustion with oxygen increases proportion of water vapor in fur-

Susanna Airaksinen, Konsta Siltala, Juho Haapakangas, Anne Heikkilä, Qifeng Shu Process metallurgy, University of Oulu, Finland

nace gas atmosphere. Oxidizing atmosphere produces oxide scale on the steel surface, and higher water vapor content has an increasing effect on the oxide scale formation [3]. After reheating, oxide scale is removed by hydraulic descaling to provide cleaner surface for hot rolling process.

La Metallurgia Italiana - July-August 2026

pagina 13

Memorie scientifiche - Decarbonizzazione Hydraulic descaling is based on thermal shock by water

In this study, oxides gas combustion of low-carbon steels

for hot surface of steel and mechanical impact by high

was studied under isothermal tests at 1200 °C for 2 hours

pressure jets with descaling parameters such as pressure,

using simulated combustion gas atmospheres with 1%

working distance, and lead angle [4]. Thermal shock has

and 6% free oxygen. The aim of the work was to investi-

wider impact area compared to mechanical impact, and

gate how the change of combustion method from natural

it is observed to be the main method for descaling [5, 6].

gas to hydrogen and air-fuel to oxyfuel affects oxide scale

Efficiency of thermal shock is based on different thermal

descalability using water thermal shock.

expansion coefficients of steel and oxide scale, which cause cracking on oxide scale and peeling of it from the

MATERIALS AND METHODS

steel surface [5].

Two different low-carbon steel grades were supplied by Ovako Imatra Oy Ab. Composition of steel grades are pre-

Steel elemental composition and heating conditions

sented in table 1. The sample size was 12 mm ˣ 12 mm ˣ

(temperature, time, atmosphere) were observed to affect

30 mm, and the actual dimensions of each sample were

the descaling. Increasing silicon and nickel contents de-

measured using average of three measurements for the

velop entanglement structure of oxide-steel interface,

determination of surface area. A diameter of 2 mm han-

decreasing descaling efficiency.[1] Free oxygen content

ging hole was drilled on the top of each sample. Before

in furnace gas atmosphere has found to have the most

heating tests, the samples were polished with SiC 220 grit

significant difference on thickness of residual oxide sca-

paper, cleaned with ethanol, and dried using temperature

le on the steel surface using 1150 °C temperature [7]. In-

of 105 °C.

crease of water vapor content from 18 to 32% based on air-combustion change from natural gas to hydrogen is not observed to affect oxide scale removability by water jets [8]. Tab.1 - Composition of low-carbon steels (wt.%). STEEL COMPOSITION Steel

0.15

0.22

1.16

0.01

0.03

0.17

0.13

0.03

0.21

0.02

0.14

0.29

0.55

0.01

1.62

1.51

0.26

0.20

0.03

Heating tests were performed in a vertical tube furnace,

is used as fuel gas in calculations for heating atmosphere

producing thermogravimetry (TG) data by hanging sam-

composition after combustion. Studied atmospheres

ple inside the furnace from the digital scale. Time of iso-

were methane-air (MA), methane-oxygen (MO), and hy-

thermal heating at 1200 °C was 2 hours. The sample was

drogen-oxygen (HO). Different shares of excess oxidant

placed inside the furnace with 100% nitrogen atmosphere

were used in calculations to provide suitable free oxygen

to prevent oxidation during pre-heating for 10 minutes

content to the heating atmosphere. Gas composition of

before test. After test, the sample was removed from the

each heating atmosphere is presented in table 2. During

furnace and placed in the cooling box with argon gas flow

test, the gas mixture of heating atmosphere was fed to the

or dipped in the water vessel for faster cooling.

furnace at 2 L min-1.

Heating atmospheres simulate the combustion of nat-

After heating tests, the samples were cold mounted in ep-

ural gas or hydrogen with air or oxygen as oxidant. The

oxy, cut in half, and polished for cross-section character-

main component of natural gas is methane (CH 4), which

ization. Digital microscope was used for characterization

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 14

Scientific papers - Co2 Mitigation of oxide scale structure and measurement of structural

steel matrix was measured from all penetrations on one

lengths. Average thickness of oxide scale at oxide-steel

sample side. FESEM (Zeiss Ultra plus) equipped with EDS

interface after thermal shock was measured from the

was used for analysis of oxide scale structure with chem-

three points at center area of each sample side (12 points

ical composition. FESEM imaging was performed using

in total). Average penetration depth of oxide scale into the

backscattered electrons (BSE).

Tab.2 - Gas composition of heating atmospheres (vol.%). GAS COMPOSITION Atmosphere ID

CO2

H2O

MA1

9.1

18.1

71.8

1.0

MA6

6.8

13.6

73.6

6.0

MO1

33.0

66.0

1.0

MO6

31.3

62.6

6.0

HO1

99.0

1.0

HO6

94.0

6.0

RESULTS AND DISCUSSION

Increase of water vapor content in furnace gas atmosphere,

Differences in oxide scale formation

when the fuel gas is changed from methane to hydrogen

Total weight gain results of samples are presented in ta-

and oxygen is used as oxidant compared to air, increased

ble 3 and weight gain with respect to time is presented in

oxidation for both steels. In comparison between MA6

figure 1. The results show that higher free oxygen con-

and HO6 atmospheres, oxide scale formation increased

tent (6% O 2) in furnace atmosphere produced more oxide

by 55% for Steel A and 41% for Steel B. Heating methods

scale compared to lower oxygen content (1% O2) for both

with higher free oxygen content have the lower propor-

steel grades, as expected based on literature [7, 9-10]. Ef-

tions of water vapor and carbon dioxide in atmosphere.

fect of free oxygen content was greater for methane-air

However, based on the oxidation results that higher O 2

(MA) method than hydrogen-oxygen (HO) method, when

content produces more oxide scale, the decrease in H2O

the increase of weight gain was 56% between MA meth-

and CO 2 content was not as significant as amount of free

ods and about 20% between HO methods. Correspond-

oxygen in these heating conditions.

ingly, a greater effect of free O 2 in heating atmosphere on oxide scale formation has also been observed in dynamic

Amount of oxide scale was higher for Steel A compared to

heating for MA method compared to HO method, when

Steel B using all studied atmospheres, which was attribut-

oxygen content changed from 1% to 2.5% [10]. Difference

ed to the lower Ni and Cr amounts of Steel A. The higher

between free oxygen contents is lower for HO method

Ni content of Steel B presumably reduced the oxidation

due to having significantly higher water vapor content.

rate due to the slow diffusion of nickel in iron, causing

Water vapor promotes internal oxidation of iron by inward

nickel enrichment at oxide-steel interface. Diffusivity of

transport and dissociation of H 2O, producing oxygen in-

iron and oxygen is lower in nickel than in iron, reducing

side the oxide scale [11]. Thus, at high water vapor con-

oxide scale formation. [12] Furthermore, higher chromi-

tents in gas atmosphere, the effect of H 2O produced ox-

um alloying can form FeCr2O 4, which acts as a diffusion

ygen increases, decreasing the difference between HO1

barrier for ions, decreasing the oxidation rate [13]. Steel

and HO6 methods.

A has higher Mn content than Steel B, which can decrease the oxidation rate with high manganese content at 650 °C

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Memorie scientifiche - Decarbonizzazione [14]. However, Fe-Mn alloys with low manganese con-

study, the effect of Mn on oxide scale formation remained

tents (1-5 wt-%) were not detected significant difference

low in relation to chromium and nickel.

in oxidation rates at 1150 °C for 20 minutes [15]. In this

Tab.3 - Total weight gain of samples after heating test (mg/cm2) TOTAL WEIGHT GAIN Steel

MA1

MA6

MO1

MO6

HO1

HO6

114.6

178.3

214.3

264.6

224.3

276.5

113.2

176.7

191.7

246.0

212.0

248.9

Fig.1 - Weight gain during heating tests: a) Steel A and b) Steel B.

Oxide scale structures using different furnace atmo-

Shape of pores inside the oxide scale was different be-

spheres for both steel grades are presented in figure 2.

tween atmospheres, because the shape was more hori-

Low O 2 produced sharp-shaped surface on the oxide-gas

zontally layered for MA atmospheres and round-shaped

interface, while the surfaces of high O2 samples were

for oxyfuel atmospheres (MO, HO). Difference of pore

smooth. Due to low O2 levels, iron oxide formed is mainly

shapes is discussed in previous study [17]. Furthermore,

wüstite (FeO), because it requires lower partial pressure

Steel B exhibited visually higher porosity and a greater

compared to magnetite (Fe 3O4) and hematite (Fe 2O3), but

number of pores than Steel A in the MO and HO atmo-

magnetite precipitates is found inside and above wüs-

spheres, which may be attributed to differences in alloy-

tite layer. Using higher O 2 content (6%), magnetite layer

ing between the steel grades. For example, nickel is pre-

and a thin hematite layer formed above the wüstite layer

sented to increase oxide scale porosity. Due to difference

as seen in figure 3 and table 4. Similar observations from

in diffusion rates of iron and nickel, outward diffusion of

outer iron oxide phases are presented in previous studies

iron generates and condensates vacancies at oxide-steel

[10,16].

interface, forming voids [12, 18].

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Scientific papers - Co2 Mitigation

Fig.2 - Overview of oxide scale structures using different atmospheres.

Fig.3 - Iron oxide phases at oxide-gas interface for Steel B with MA1 on the left and MA6 on the right.

Tab.4 - Elemental contents of EDS poinst (wt-%) from figure 3. ELEMENTAL CONTENTS Point

75.4

76.5

81.0

72.0

76.8

81.3

78.0

24.6

23.5

19.0

28.0

23.2

18.7

22.0

Iron oxide

Fe3O4

FeO

Fe2O3

Fe3O4

FeO

Fe3O4

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Memorie scientifiche - Decarbonizzazione Oxide-steel interfaces after heating using 6% free oxygen

ide-steel interface is both thicker and more uniform us-

in gas atmospheres are presented in figure 4. A horizon-

ing MA method compared to MO and HO methods. Pore

tal crack formed near the steel surface due to different

structure can affect the cracking behavior during cooling

shrinking behavior of scale and steel during cooling [19].

at interface because more horizontal layered pores for

When looking at oxide scale below the uniform horizon-

air-fuel method can provide easier cracking route com-

tal crack, methane-air method left an uneven and thicker

pared to round-shaped pores for oxyfuel methods.

oxide scale at the interface for Steel A, while oxide scale attached at interface is more layer-like after oxyfuel methods. For Steel B, thickness of oxide scale layer at ox-

Fig.4 - Oxide-steel interface after heating with different methods.

Oxide-steel interface structures of studied steel grades

are enriched with manganese for Steel A and manganese

are presented in figure 5, and the elemental composition

and chromium for Steel B as seen from EDS maps. Ox-

of EDS points is presented in table 5. Based on EDS the

ide-steel interface structure of Steel B is more entangled,

lighter gray phases in oxide are wüstite (Points 1 and 4),

and formation of pores is higher, which correlates with

darker gray phases are fayalite (Points 2 and 5), and white

higher amounts of metallic phases. Oxide scale penetra-

phases are metallic (Points 3 and 6). Metallic phases for

tion inside the steel matrix into grain boundaries is more

Steel B are more strongly enriched with nickel compared

significant for Steel B, as also seen in figure 4.

to Steel A. Inside the steel matrix the small oxide nuclei

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Scientific papers - Co2 Mitigation

Fig.5 - Oxide-steel interface structure with EDS maps for Steel A: a) and b), and Steel B: c) and d). Tab.5 - Elemental contents of EDS poinst (wt-%) from figure 5. ELEMENTAL CONTENTS Point

79.0

19.6

0.2

0.9

0.3

56.3

27.6

13.6

2.5

90.2

7.4

1.6

0.7

76.8

20.2

0.3

2.7

62.2

25.1

11.0

1.0

0.7

86.9

0.7

2.7

9.7

Differences in descaling efficiency by thermal shock

scale was detached from the samples with lower O2 in at-

Steel samples oxidized with different furnace gas atmo-

mosphere. Difference between heating methods for ther-

spheres and descaled by water thermal shock are pre-

mal shock descaling can be based on higher H 2O and O 2

sented in figure 6. The results show that descalability of

contents in atmosphere that produce thicker oxide scales

Steel A was better than Steel B even though the amount

with better thermal insulation [20].

of oxide formation was slightly higher for Steel A using all heating atmospheres. Transition from methane-air to

Figure 6 shows that sharp-shaped surfaces from both MA1

hydrogen-oxygen affected the descaling efficiency of

samples were partially removed on the thick iron oxide

Steel A, decreasing the amount of thick outer oxide scale

layer when this thick layer remained on the steel surface.

detached from the surface. For Steel B, the oxide scale

Similar sharp-shaped surface detaching behavior was not

was detached from the surface only after heating in meth-

observed from MO1 and HO1 samples. As seen in figure

ane-air atmosphere, although the amount of removed

2, MA1 formed more horizontally shatter scale structures

scale was minor for MA6. Oxide layers were not detached

compared to other 1% O 2 containing atmospheres, indi-

after heating in methane-oxygen and hydrogen-oxygen

cating less adhesion inside the oxide scale.

atmospheres. In addition to the heating method, free oxygen content had effect on descalability: more oxide

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Memorie scientifiche - Decarbonizzazione

Fig.6 - Oxide scales after descaling by thermal shock.

Depending on the furnace gas atmosphere, different

method does not have crack above the porous zone. The

amounts of thick iron oxide scales are removed from the

cause of the cracks was suggested to be a lower adhesion

surface after descaling by thermal shock. Figure 7 shows

in the oxide scale layers when cooling causes mechanical

sample sides for MA and MO methods, which still have

stress due to higher shrinkage of steel compared to oxide

iron oxide scale left on the surface. Oxide scale of HO

scale. Different pore structure can also be the reason for

methods is very similar to MO methods. Thermal shock

horizontal cracking. As seen in figure 4, outer line of pores

cooling has significantly detached the outer iron oxide

inside the oxide scale of MA6 samples is almost connect-

layer, leaving interface oxide on the steel surface. Only

ed horizontally to form continuous crack, while similar

Steel A with MA1 method does not have a clear cooling

pore merging is not detected for oxyfuel samples.

crack in the center of the one sample side. However, all sharp-shaped outer oxide is removed on the remain-

Both vertical and horizontal cracks promote oxide scale

ing oxide layer and other three sample sides are without

removal in industrial descaling process, in which includes

whole layer of outer iron oxide.

mechanical impact by water jets to remove oxide scale. Difference in pore structure and cracking between air-fu-

In addition to cooling cracks and sharp-shaped outer

el and oxyfuel methods can be reason for observation by

oxide removal from both steels in MA1 method by ther-

Adolfi et al. [19] that oxide scale formed using oxyfuel

mal shock, fast cooling causes more vertical cracking of

method comes off steel surface in larger pieces compared

oxide scales compared to ones without thermal shock.

to air-fuel method.

Furthermore, oxide scale formed using oxyfuel methods is more cohesive, while air-fuel methods have horizontal crack between more pores containing inner oxide and outer iron oxide with wide vertical voids. Similar cracking between porous inner wüstite and outer magnetite precipitates containing wüstite layer was found after air-fuel method of propane by Adolfi et al. [19], while oxyfuel

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Scientific papers - Co2 Mitigation

Fig.7 - Oxide scales after descaling by thermal shock. Oxide-steel interfaces after descaling by water thermal

oxide penetration into the steel matrix and entanglement

shock are presented in figure 8. Steel A has more un-

structure formation due to nickel and silicon alloying [1].

even oxide layers on the steel surface compared to more

Furthermore, increase in chromium content has been re-

continuous layers of Steel B, indicating weaker scale ad-

ported to increase the scale adhesion [13].

hesion. Stronger adhesion of Steel B is based on higher

Fig.8 - Oxide-steel interface after descaling by thermal shock. Measured thickness averages of interface oxide scale re-

observed in samples without thermal shock descaling

siduals on the steel surface and penetration depth aver-

(figure 3).

ages of oxide scale pegs are presented in figure 9. Transition from methane-air to hydrogen-oxygen decreases

Average penetration depths of oxide scale pegs into the

the thickness of oxide scale at interface, indicating that

steel matrix are about 30 µm for Steel A and about 55 µm

heating method change can even enhance the descaling

for Steel B as seen in figure 9b. Variations of depths is mi-

efficiency. Even if the average thickness using HO meth-

nor and therefore no significant effect of heating method

od slightly increased compared to MO methods for Steel

on oxide scale peg depths can be observed. In consid-

A, the thickness of the residual scale is still lower than

eration of interface oxide thickness and depths of oxide

the methane-air method (MA6). Higher unevenness and

pegs, there is not a noticeable decrease in descaling effi-

variation in measured average thickness of residual oxide

ciency in transition of heating methods from methane-air

scales after MA methods can be the result of different pore

to hydrogen-oxygen, when industrial descaling with me-

structures between air-fuel and oxyfuel methods. Similar

chanical impact can also remove thick outer iron oxide

unevenness of internal oxide scale after MA methods was

scale layer from the steel surface.

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Memorie scientifiche - Decarbonizzazione

Fig.9 - Heating atmosphere differences for oxide-steel interface after thermal shock: a) oxide scale thickness at interface and b) penetration depth of oxide scale.

CONCLUSIONS

Thickness of residual oxide scale at oxide-steel interface

The influence of simulated furnace atmosphere between

decreased between methane-air and hydrogen-oxygen

current

hydro-

methods for both steel grades, and oxide scale pene-

gen-oxygen heating methods on thermal shock descaling

tration depths were similar between methods. Thus, the

efficiency was investigated for low-carbon steels. Oxide

change of the heating methods has not been found to

scale formation increased by increasing amount of water

have a decreasing effect on oxide-steel interface quality

vapor and oxygen in the heating atmosphere, and the des-

after thermal shock descaling.

methane-air,

methane-oxygen,

and

caling efficiency by thermal shock decreases by changing heating method from methane-air to hydrogen-oxygen. The higher amount of nickel and chromium containing

ACKNOWLEDGEMENTS

Steel B oxidized less in all studied heating methods, but

This research was part of the Strategic Research Coun-

its descaling efficiency by water thermal shock was weak-

cil within the Research Council of Finland project JustH-

er compared to Steel A. Lower free oxygen content (1%)

2Transit (decision 358422). The authors wish to thank

removed oxide from a wider sample surface area, but

Ovako Imatra Oy Ab for supplying materials, and the Cen-

regardless of free oxygen content, oxyfuel based oxide

tre for Material Analysis, University of Oulu, Finland, for

scales for Steel B remained unchanged after descaling.

supporting this work.

REFERENCES [1] [2]

[3] [4]

Melfo W., Bolt H., Rijnders M., Staalman D., Castro C.B., Crowther D., Jana B., Experimental study on primary scale formation and descalability on steels containing Ni and Ni+ Si. ISIJ int. 2013;53:866–873. Ramírez-Cuellar J., Guerrero-Mata M.P., Leduc L.A., Colás R., Modelling the oxide growth during hot rolling of low carbon steel in a compact mill. Conference Proceedings - International Conference on Thermomechanical Processing: Mechanics, Microstructure & Control. 2003. p. 418–422. Haapakangas J., Riikonen S., Airaksinen S., Heikkinen E.P., Fabritius T., Oxide scale formation on low-carbon steels in future reheating conditions. Metals. 2024;14:189. Ojiako T.P., Buchely M.F., Lekakh S., O’Malley R.J., Osei R., Tayebali T., Parametric analysis of water jet descaling efficiency of reheated continuously cast thin slab. Steel Res. Int. 2026;97:758–772.

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Scientific papers - Co2 Mitigation

[5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20]

Bendig L., Raudenský M., Horský J., Descaling with high pressure nozzles. Conference Proceed-ings - the 17th European Conference on Liquid Atomization and Spray Systems. 2001. pp. 742-747. Horsky J., Raudensky M., Vavrecka L., Experimental study of hydraulic descaling. Conference Pro-ceedings - 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, 2007 Jul 1-4; South Africa; 2007. Basabe V.V., Szpunar J.A., Effect of O2 in heating atmosphere on hydraulic descaling in hot rolling of low carbon steel. ISIJ int. 2008;48:467-474. Luzzo I., Cirilli F., Jochler G., Gambato A., Longhi J., Rampinini G., Feasibility study for the utiliza-tion of natural gas and hydrogen blends on industrial furnaces. Mater Tech. 2021;109:306. Abuluwefa H.T., Guthrie R.I.L., Ajersch F., Oxidation of low carbon steel in multicomponent gases: Part I. Reaction mechanisms during isothermal oxidation. Metall Mater Trans A. 1997;28:1633–1641. Haapakangas J., Airaksinen S., Heikkinen E.P., Fabritius T., Oxidation of Carbon Steels in Novel Reheating Conditions: Changes to Oxidation Kinetics. Metall Mater Trans B, 2025;56:3762–3773. Rahmel A., Tobolski J., Einfluss von wasserdampf und kohlendioxyd auf die oxydation von eisen in sauerstoff bei hohen temperaturen. Corros. Sci, 1965;5:333–346. Vedaei-Sabegh A., Morin J.B., Jahazi M., Influence of Nickel on High‐Temperature Oxidation and Characteristics of Oxide Layers in Two High‐Strength Steels. Steel Res Int. 2020;91:1900536. Takeda M., Kushida H., Onishi T., Toyama M., Koizumi F., Fujimoto S., Influence of oxidation tem-perature and Cr content on the adhesion and microstructure of scale on low Cr steels. Oxid. Met. 2010;73:1–13. Park S.-Y., Xiao X., Kim M.-J., Lee G.-T., Hwang D.-H., Woo Y.-H., Lee D.-B., Oxidation of Fe-(5.3-29.8)% Mn-(1.1-1.9)% Al-0.45% C Alloys at 550-650℃. Corros. Sci. Technol. 2022;21:53–61. Aghaeian S., Sloof W.G., Mol J.M.C., Böttger A.J., Initial high-temperature oxidation behavior of Fe–Mn binaries in air: the kinetics and mechanism of oxidation. Oxid. Met. 2022;98:217–237. Airaksinen S., Haapakangas J., Gyakwaa F., Heikkinen E.P., Fabritius T., Utilization of hydrogen fuel in reheating furnace and its effect on oxide scale formation of low-carbon steels. Int. J. Hydrog. Energy. 2025;140:1212–1220. Haapakangas J., Airaksinen S., Heikkinen E.P., Fabritius T., Oxide Scale Morphology of Carbon Steels Under Novel Reheating Conditions. Steel Res Int. 2026:1–13. Oleksak R.P., Kapoor M., Perea D.E., Holcomb G.R., Doğan Ö.N., The role of metal vacancies during high-temperature oxidation of alloys. npj Mater. Degrad. 2018;2:25. Adolfi J., Ekman T., von Schéele J., Blasiak W., Scale formation and surface quality of carbon steel at oxyfuel heating. Steel Rolling. Paris; 2006. Sherwood W., Shatynski S.R., The effect of temperature on oxide scale adherence during descaling operations. Surf. technol. 1984;21:39–51.

TORNA ALL'INDICE >

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Attualità industriale - Industry news

DOI 10.36146/2026_0708_24

Development and application of a particle conversion model for the utilization of biochar in an electric arc furnace to substitute fossil coal T. Griessacher, M. Blank, K. Supancic, C. Schlögl, I. Obernberger A novel adaptation of a layer model for single-particle conversion is presented, explicitly accounting for diffusion effects and dynamic changes in particle structure (e.g. specific surface area, porosity, pore diameter) during conversion. The model has been parameterized using both literature data and new experimental results and is applied to both petrol coke as a reference and biochar under realistic EAF gas atmospheres (CO/CO2 mixtures) and temperatures. This dual approach enables direct comparison and transferability of kinetic parameters across material classes. The research addresses a critical gap in the systematic evaluation of biochar for metallurgical use, by focusing on the conversion of coal particles under conditions typical for those applications. By establishing quantitative relationships among key material parameters (density, volatile content, specific surface area, pore size) and conversion kinetics, the study offers a rational basis for selecting and optimizing biochar for this industrial application. The findings provide guidelines for the production and pre-treatment of biochar tailored to EAF injection, supporting decarbonization strategies in steelmaking. The validated modelling framework can be extended to other high-temperature applications, facilitating the broader adoption of renewable carbon sources in the metallurgical sector.

KEYWORDS: EAF; BIOCHAR; SLAG FOAMING; PARTICLE CONVERSION; MODELLING.

INTRODUCTION AND BACKGROUND The need to reduce CO 2 emissions from the metallurgical industry has led to increased research in this area in recent years. For example, extensive research has been conducted on the use of biochar as a substitute for coke or coal in the blast furnace process and upstream processes (sintering, coking), which has demonstrated the fundamental suitability of biochar as a substitute for coal/ coke [1, 2, 3, 4]. However, current projects in the steel industry are primarily focused on converting blast furnaces to electric arc furnaces (EAF) and/or the use of hydrogen

Thomas Griessacher

Stahl - und Walzwerk Marienhütte GmbH, Graz, Austria

Martina Blank, Klaus Supancic, Christoph Schlögl, Ingwald Obernberger BIOS Bioenergiesysteme GmbH, Graz, Austria

as an energy source and reducing agent. The use of biochar in the EAF has been investigated, amongst other things, in two major EU-wide research projects [5, 6]. In modern EAFs, the proportion of energy input from fossil fuels accounts for over 40% of the total energy input.

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Industry news - Attualità industriale EAFs typically use fossil carbon materials—most com-

its thermally insulating properties and enables slag sepa-

monly petroleum coke or anthracite—to create slag

ration at the end of each heat. The approach models the

foaming in the refining phase. These materials account for

conditions in an EAF using CFD simulations und the ther-

approximately 5-10% of total CO2 emissions in EAF steel

mal and chemical conversion of individual coal particles

production. Substituting these materials with biogenic,

employing a layer-based model tailored to EAF condi-

carbon‑neutral alternatives could avoid 30-60 kg CO 2 per

tions. The model parameters are calibrated using experi-

ton of steel.

mental data from laboratory-scale decomposition tests of

Apart from the use of charge coal during the charging pro-

biochar as well as petrol coke. The model is then applied

cess of the EAF the main application of petroleum coke or

to calculate the conversion of biochar and petrol coke

anthracite in the EAF is the use as injection coal for foam

under EAF conditions (gas atmosphere and temperatures)

slag formation. The combined injection of O 2 and C via

and assesses the performance of biochar regarding slag

working lances or injectors into the interface between the

foaming.

melt and the slag leads to the formation of CO bubbles. Furthermore, the C in the coke reacts with the iron ox-

METHODOLOGY

ide in the slag and reduces it to metallic Fe, also forming

General approach

CO bubbles. These cause the slag to foam. In the EAF, the

The investigations were carried out in stages:

foamed slag serves the following purposes:

Steady-state and transient CFD simulations of the

•

Absorption of impurities from the scrap

expected heating characteristics and environmen-

•

Increased energy transfer efficiency: the foam slag

tal conditions of the biochar upon injection into the

shields the arcs, reducing energy losses through the

EAF to determine the framework conditions for bio-

water-cooled furnace walls and ceiling

char conversion in the EAF, in comparison to the be-

Stabilisation of the arcs and reduction of noise emis-

haviour of the petroleum coke used to date.

•

sions

Detailed single-particle simulations of biochar conversion, considering the temperature profiles and gas

Biochar has emerged as a promising candidate to sub-

compositions derived from step 1, as well as a com-

stitute fossil carbon carriers due to its high carbon con-

parison of the results to the conversion behaviour of

tent and potential for renewable sourcing. However,

currently used coke as a reference process.

its behaviour during injection, heating, gasification and

Conducting a sensitivity analysis to examine the rele-

slag‑foaming differs strongly from fossil coals. Under-

vant factors influencing biochar conversion regarding

standing these differences requires a comprehensive

the parameters of chemical composition and content

approach that includes systematic experimental decom-

of volatile components, particle size, specific surface

position tests carried out under controlled atmospheres,

area, pore diameter and particle density (or porosity).

as well as detailed modelling of particle‑scale conversion

Overall assessment of the results, considering rele-

kinetics. Furthermore, it is essential to validate the find-

vant influencing factors regarding biochar properties

ings under industrial EAF conditions to ensure practical

in relation to foam slag formation capacity (CO release

applicability.

over time), as well as the definition of relevant biochar compositions in this regard.

OBJECTIVES The primary objective is to enable the substitution of fos-

Testing the findings of the investigations in trials with tailored biochar at the EAF of Marienhütte.

sil-based injection coals with biogenic coals in EAF operation by establishing robust criteria for material suitability,

CFD simulations of the expected environmental con‑

especially concerning the ability of the coal to produce

ditions in an EAF

foaming slag. This is paramount for EAF operation, be-

To investigate the conditions for the injection of fossil

cause slag foaming increases the efficiency of the EAF by

coal and biochar into the EAF at the Marienhütte during

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Attualità industriale - Industry news the refining phase, the following CFD simulations were

steel  the simulations carried out under this head-

carried out:

ing enable an assessment of the flow and distribution

Steady-state gas-phase simulations for the side wall burn-

of the foamed slag during the refining phase, once the

er (Oxygen injection with enveloping CH 4-flame) without

slag has already been foamed.

considering blown coal, molten steel and foaming slag  this simulation allows for an assessment of the unmodi-

Detailed single-particle simulations of biochar con‑

fied side wall burner and the burn-out under these con-

version

ditions

The calculations presented here were carried out using a

•

Steady-state multi-phase simulations for fossil coal

computational model for the thermal conversion (drying,

(petroleum coke) and biochar when injected into the

pyrolysis, combustion) of individual fuel particles, devel-

EAF, considering the molten steel (without foaming

oped by BIOS (shell model/layer model, [7]).

slag) this simulation allows the situation to be as-

In the basic model, a fuel particle is treated either as a

sessed approximately before primary foaming begins

spherical or cylindrical particle. It is divided into five lay-

Transient multi-phase simulations for fossil coal (pe-

ers, each corresponding to a stage in the combustion pro-

troleum coke) and biochar when injected into the

cess (wet fuel, dry fuel, partially pyrolysed fuel, charcoal,

EAF, considering the foaming slag and the molten

ash, see figure 1).

•

Fig.1 - Layers considered in the basic layer model.

The interfaces between the individual shells correspond

For use in this project, the layer model was modified to

to the reaction fronts of the ongoing processes (drying,

represent the behaviour of the coal particles under con-

pyrolysis, carbon burnout/carbon gasification), which

sideration. The layers for drying and pyrolysis were de-ac-

move towards the centre of the particle during combus-

tivated (particles initialised as coal). The proportions of H

tion.

and O present in the coal, as determined by analysis, are

This model can describe the thermal conversion of the

assigned to volatile intermediate products of carbonisa-

particles: internal temperature gradients, mass losses of

tion. The central focus of the modelling is the reaction of

the particles, and time-dependent changes in particle size

the coal with CO2, as in the EAF (based on equilibrium cal-

and density.

culations) a gas atmosphere of approx. 85 vol% CO and 15

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Industry news - Attualità industriale vol% CO 2 is expected, with other gases occurring only in

ture. These effects were considered in the kinetic calcu-

small quantities.

lations.

For this conversion reaction (C + CO2  2CO), a volumet-

The kinetics of the conversion reactions were analysed

ric conversion of the coal in the region reached by the CO 2

applying a comprehensive literature research and were

was assumed since the reaction rates are generally slower

further adapted and validated by experimental data, de-

than, for example, those involved in the combustion of

rived from particle conversion tests with petroleum coke

coal with O 2, and (depending on the prevailing tempera-

and biochar under various temperatures and gas atmo-

tures, particle sizes and CO 2 supply) the reactant CO2 can

spheres like those in an EAF.

diffuse into the coal particles due to their porous struc-

Fig.2 - Schematic conversion of coal/biochar particles with CO2. The adapted and validated model was used to evaluate the

in trials in the EAF at Marienhütte, where 100% petroleum

conversion behaviour of biochar and petroleum coke as

coke was substituted by tailored biochar for several heats.

a reference under EAF conditions (derived from the CFD

The performance in terms of coal consumption, metallic

simulations performed).

yield, slag foaming level and FeO-content in slag was recorded and compared with the data from reference heats

Sensitivity analysis to examine the relevant factors in‑

produced before and after the trials.

fluencing petroleum coke and biochar conversion in

The results of the work described are shown in the follow-

an EAF and definition of relevant biochar characteris‑

ing sections.

tics relevant for slag foaming The adapted and validated layer model was used to eval-

RESULTS

uate the influence of relevant properties of the carbon

Definition of environmental conditions in an EAF for

carriers such as density, particle size, specific surface area

injected carbon carriers based on CFD simulations

or porosity on the behaviour of biochar under EAF condi-

The detailed results of the CFD simulations are beyond

tions compared to petroleum coke as a reference. Based

the scope of this paper, so only some selected results

on the findings, the relevant parameters for biochar suit-

relevant for the further use in the particle conversion cal-

able as injection coal for slag foaming have been derived.

culations are presented here. The simulations were performed with the standard blowing coke currently used

Industrial trials with tailored biochar in the EAF at

at Marienhütte and milled biochar made from hardwood.

Marienhütte

The milling of the biochar was performed based on find-

Biochar tailored to the parameters defined was then used

ings from earlier pre-tests with unmilled hardwood bio-

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Attualità industriale - Industry news char (d(50) > 1 mm) that showed only slight foaming and

The reaction rate depends on the available surface area of

unused biochar particles swimming on the molten, hardly

the carbon. The specific surface area is particularly rele-

foamed slag. The milled biochar featured a slightly higher

vant here, as CO2 can diffuse into the interior of the par-

particle size (d(50) approx. 0.46 mm) than the petroleum

ticles through the porous structure of the carbon. The

coke used (d(50) approx 0.39 mm).

composition of the gas surrounding the carbon particles

The chemical composition of the petroleum coke and

has a major influence on the reaction rate. In the pres-

hardwood biochar were derived from wet chemical anal-

ence of CO, the reaction is significantly slowed down, as

ysis. The main difference between the two carbon carri-

CO is adsorbed onto the surface of the carbon, thereby

ers were the C-content (approx. 97.6 % of dry weight, ash

reducing the surface area available for the reaction with

free for the petroleum coke compared to approx. 87.3%

CO2. This effect varies in intensity for different types of

for the biochar and the amount of volatiles (<1 % of dry

carbon (differences were investigated between metallur-

weight for the petroleum coke compared to approx. 15 %

gical coke, coconut-based biochar and graphite), as the

of dry weight for the biochar).

structure of the carbon matrix differs (i.e. it is more or less

The results show that most of the blown coal/biochar par-

crystalline in nature).

ticles reach the surface of the melt (approximately 99%

Consequently, the reaction rate is influenced by the fol-

of the mass for both biochar and fossil coal). Only the

lowing parameters of the coal/biochar:

lightest particles are carried upwards by the gas flow. The

•

Specific surface area: linear dependence; however, a

particles of both types of blown coal have an average resi-

small pore size combined with a large specific surface

dence time of approximately 0.05 s until they get into con-

area limits the reaction rate (diffusion limitation, see

tact with the melt. The particles are heated as they travel

below)

from the injector to the surface of the melt, although a wide variation in the values can be observed (typical range between 210 and 350°C). Once in the melt, the particles are considered to stay in the melt/the foaming slag till they are fully decomposed.

• • •

Temperature: high temperatures significantly accelerate the reaction rate CO2 concentration: a higher CO 2 concentration increases the reaction rate CO concentration: a higher CO reduces the reaction

From the simulations carried out, the average ambient

rate; the lower the temperature, the greater the re-

conditions and particle temperatures along the residence

duction

time of the injection coal particles for both types of injection coal can be derived from the evaluations conducted

The linear dependence of the specific surface area on the

along the particle trajectories.

reaction rate means that the model can be applied to dif-

They were used as boundary conditions for the single-par-

ferent types of coal (fossil coal and biochar). The above

ticle simulations described below. This allows the differ-

correlations are valid if full pore diffusion is possible.

ences between fossil coal (petroleum coke) and biochar

However, at higher temperatures, with larger particle

in terms of the behaviour of the particles in the EAF at the

diameters and faster reaction rates, this is no longer the

start of the refining phase and during the refining phase to

case, and the decomposition reaction takes place only

be examined and evaluated in detail.

within a specific region of the particle (as described in [9]). In the limiting case, a sharply defined reaction front forms

Development of a single-particle conversion model

at the particle surface. To determine the scope of valid-

for injection coal in the EAF

ity of the kinetics and to account for a limitation due to

Several relevant studies have been performed regarding

diffusion in the model, an approach according to [9] was

the reaction kinetics of injection coal in an EAF [8, 9,10].

implemented and the results compared with data from the

Based on a thorough evaluation of the relevant reaction

same reference [9]. This showed that neglecting diffusion

C+ CO2  2 CO, the following findings could be derived

leads to a distortion of the results. The influence of diffu-

in [8]:

sion increases with increasing temperature (the higher the

La Metallurgia Italiana - Luglio-Agosto 2026

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Industry news - Attualità industriale temperature, the more diffusion slows down the reaction

over the entire experiment was determined gravimetrical-

rate) but decreases with increasing pore diameter and po-

ly as a reference.

rosity (the large the pore size and the larger the porosity,

Furthermore, based on database values for biochar and

the higher the reaction rate).

analyses of samples from the decomposition tests (resi-

The adaptations of the model so far were based solely on

dues from test runs under pyrolysis conditions, or from

data from literature and did not consider changes in the

degradation tests carried out specifically for this purpose),

coal’s parameters as decomposition progresses.

correlations were derived for the changes in the structure

It therefore had to be verified in the next step by compar-

of the various coals during decomposition, which were

ing it with measurement data from laboratory tests carried

considered in the layer model.

out specifically for this purpose.

The values for specific surface area and pore size in the

Within the lab-tests, different carbon carriers (petroleum

partially decomposed samples show a linear increase in

coke and hardwood biochar) were exposed to various at-

specific surface area as decomposition progresses, ac-

mospheres (CO/CO2 mixtures, pure CO2 and pure N ) in

companied by a decrease in pore size. The pore size de-

a laboratory reactor at different temperatures (between

creases exponentially with increasing specific surface

900 °C and 1100 °C). Care was taken to ensure good flow-

area, as analyses of different biochar and petroleum coke

through of the sample and consistent particle sizes. The

samples show (see figure 3). Both correlations were im-

gas concentrations resulting from the decomposition

plemented in the layer model and used for all coals con-

were measured, and the mass loss of the sample over time

sidered (petroleum coke and biochar).

was calculated from these. The mass loss of the sample

Fig.3 - Correlation between specific surface area and pore size of different carbon carriers.

The comparison of the results of the decomposition

kinetics, parameter adjustments are necessary to describe

tests and the results gained with the adapted layer model

the decomposition of the individual coal types accurate-

showed that, although the trends visible in the results of

ly. Therefore, kinetic parameters were determined from

the decomposition tests can be forecasted by the given

the decomposition curves derived from the experiments.

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Attualità industriale - Industry news Figure 4 shows the mass conversion over time for various

used to optimise the kinetic parameters; the “Layermod-

CO2/CO atmospheres and temperatures in comparison to

el” - curves employ the final parameter set for each type

the corresponding experimental results for biochar from

of coal that were used for the simulation of the decompo-

hardwood (left) and petrol coke (right). These data were

sition of petroleum coke and biochar particles in the EAF.

Fig.4 - Mass conversion over time (calculated on dry basis) for the conversion of biochar from hardwood (left) and

petrol coke (right). The solid lines represent experimental results from lab-scale reactor tests, the dashed lines are results from layer model calculations with an optimised set of kinetic parameters.

Explanations: experimental … mass conversion based on laboratory experiments; layermodel … mass conversion based on calculations using the adapted layer model; CO2/CO xx/yy … gas composition in vol% (xx: CO2, yy: CO)

Results of single-particle simulations under EAF con‑

of the particles. These profiles were used in conjunction

ditions and sensitivity analysis

with the adapted and extended layer model (including the

Based on the CFD simulations carried out for the EAF (for

kinetics derived from the decomposition tests) for sin-

biochar and fossil coal, see above), the environmental

gle-particle calculations, including sensitivity analyses.

conditions of the injected coal particles were determined

This allows relevant factors influencing the decomposi-

along their path from entry into the EAF until they strike

tion rate—such as particle density, diameter, specific sur-

the boundary layer between the slag and the molten bath

face area and pore size, as well as volatile content—to be

(or until they exit the area relevant to the foam slag).

investigated.

From this, profiles were extracted for the temperatures in

It is assumed that, upon their first direct contact with

the vicinity of the particles (temperature of the surround-

slag, the coal particles react immediately with it, and a gas

ing medium or radiation temperature), the relative veloc-

bubble forms around each particle. The gas composition

ity of the particles with respect to the surrounding me-

within the bubbles is approximated to correspond to the

dium, and the prevailing gas composition in the vicinity

equilibrium composition in the EAF (due to the good mix-

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Industry news - Attualità industriale ing in the EAF). The profiles were therefore maintained at

(shown by the almost immediate mass loss at the begin-

equilibrium conditions for the remainder of the time (du-

ning in figure 5).

ration of the refining phase: 6 minutes).

The subsequent decomposition of the particles inves-

The calculations were performed with data for petroleum

tigated takes between 2.5 and 6 minutes (depending on

coke and three different types of biochar from hardwood

the particle properties, see figure 5). Selected results of

(see table 1).

comprehensive sensitivity analyses performed are shown

Under the conditions prevailing in the EAF, the decom-

in figure 6. Biochars that feature a similar decomposition

position of the coal particles essentially only begins after

time as the reference petroleum coke (4 minutes) shall

they strike the interface between the slag and the molten

show a similar foaming performance. The decomposition

bath. The decomposition during the short period of time

time is a key factor for successful slag foaming, and the

till it hits the surface of the molten bath (along the profiles

test results on the EAF (see below) confirm this interpre-

determined from the CFD simulations) is mainly limited

tation.

to the decomposition of volatiles (pyrolysis). Therefore, the number of volatiles is almost immediately released

Tab.1 - Carbon carriers evaluated in the single particle simulations.

Explanations: Skeleton density … density of the particle without voids and pores; Envelope density … density of the particle including voids and pores; The envelope density of Hardwood 2 was not explicitly measured. Due to the similar skeleton density, a similar envelope density was assumed; void fraction … the void fraction was

calculated based the envelope and skeleton density; specific surface area according to BET adsorption method; Pore size according to BJH method.

Type of coal

Petroleum coke

Hardwood biochar 1 unmilled

Hardwood biochar 2

milled

Skeleton density

[kg/m³]

2120.0

1494.0

1570.0

Spec. surface area

[m²/g]

2.2

142.1

166.6

Pore size

[nm]

12.1

6.0

5.9

Envelope density

[kg/m³]

848.0

459.0

Water content

[% wet weight]

0.3

5.4

6.3

Ash content

[% dry weight]

1.8

7.8

10.5

Volatiles

[% dry weight]

0.4

18.8

13.1

[% dry weight]

95.4

79.3

83.2

[% dry weight]

0.2

2.9

2.5

Void fraction

[-]

0.60

0.69

0.71

d_m (mass weighted average diameter)

[mm]

0.45

1.69

La Metallurgia Italiana - July-August 2026

1.23

0.63

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Attualità industriale - Industry news

Fig.5 - Mass conversion over time (calculated on dry basis) for the conversion of biochar from hardwood and petrol

coke during the time spent in the gas phase (before hitting the melt, left) and during the full fining phase (right) in the EAF

Explanations: d_m …mass weighted mean particle diameter.

Fig.6 - Mass conversion over time (calculated on dry basis) for the conversion of biochar from hardwood and petrol

coke under EAF conditions. Left: variation of biochar envelope density; Right: variation of biochar particle diameter.

Explanations: d … average diameter, based on mass; rho … envelope density i.e. density of a single particle including pores; envelope density of biochar in the right diagram: 474 kg/m³.

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Industry news - Attualità industriale

The primary influencing factors identified are as follows

ce. The annual production capacity amounts to roughly

(see figure 6):

400.000 t. Marienhütte which is directly located in the city

•

Envelope density: A lower particle density (envelope

centre of Graz, the capitol of Styria in Austria, stands for an

density) results in a reduced decomposition time for

urban and sustainable production of rebars.

a given diameter.

The trials performed with biochar from hardwood with

Particle diameter: A smaller particle diameter also le-

particle size of 1.23 mm were done in 2025 at 7 heats in

ads to a shorter decomposition time.

a row. Usually, petroleum coal is injected via all three

Specific surface area and pore diameter: These para-

side wall burners in the refining phase. Charging coal via

meters do not vary independently and can partially

basket is not used at Marienhütte in the production pro-

compensate for each other’s effects on conversion

cess. At these trials with biochar from hardwood one of

behaviour.

these three injection points was equipped with a separate

Volatile content: Volatile matter is released within

pneumatic injection vessel to be able to use either bio-

seconds and does not contribute to slag foaming in

char and/or petroleum coke as slag foaming agent. Due to

the EAF. Consequently, a lower volatile content is ad-

successful pre-trials with that material, it was decided to

vantageous, as it decreases the necessary amount of

run for several heats solely with biochar as foaming agent

biochar for metallurgical applications.

and keep petroleum coke as back-up in case of problems

• •

•

or uncertainties. In total roughly 2000 kg of biochar were The knowledge of the influence of different biochar pro-

used in that trials. The results were rather promising and

perties on decomposition time makes it possible to defi-

can be summarized as following:

ne suitable biochar qualities which reach comparable decomposition times to fossil coke which typically should

•

also result in similar slag foaming properties. The fact that the particle diameter has a significant influence on

No visible differences in slag foaming in the refining phase

•

the decomposition time, enables, under consideration of

Immediate start of the reaction and therefore slag foaming

the other relevant parameters such as envelope density,

•

Solely no difference in yield values etc.

specific surface area and pore size, to tailor the foaming

•

No significant difference in FeO-content of slag

properties of the biochar by finetuning the particle size.

•

No detectable changes in off-gas temperature, composition, etc.

RESULTS INDUSTRIAL TRIALS

•

Slightly higher consumption of injection agent (ap-

Parallel to the theoretical evaluation backed by lab-scale

prox. 20%) due to lower carbon content and higher

tests, full-scale trials at the EAF of Marienhütte were per-

volatiles content

formed with biochar in several particle sizes, confirming the results of the particle conversion calculations. While tests with average particle sizes too small (d_m=0.63 mm) or too big (d_m=1.69 mm) didn’t show relevant slag foam formation in the refining phase, biochar from hardwood with an average mass-weighted particle size of 1.23 mm showed acceptable foaming behaviour. At Stahl- und Walzwerk Marienhütte GmbH a high productive AC-EAF with 40 t tapping capacity is in operation. The furnace is equipped with three side wall burners and one burner in the furnace door. Each of the side wall burners is able to inject carbon at a separate injection lan-

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Attualità industriale - Industry news

Fig.7 - Foaming slag operation at injection trials with biochar from hardwood.

Fig.8 - Graph of consumption values of oxygen (orange line), natural gas (blue line) and injection carbon (black line) as example for a heat during trial period.

Further trials with even better suited particle sizes (around 0.9 mm) are planned in 2026.

SUMMARY AND CONCLUSIONS

char under realistic EAF gas atmospheres (CO/CO2 mix-

A novel adaptation of a layer model for single-particle

tures) and temperatures. This dual approach enables di-

conversion is presented, explicitly accounting for dif-

rect comparison and transferability of kinetic parameters

fusion effects and dynamic changes in particle structure

across material classes. The research addresses a critical

(e.g. specific surface area, porosity, pore diameter) during

gap in the systematic evaluation of biochar for metallur-

conversion. The model has been parameterized using

gical use, by focusing on the conversion of coal particles

both literature data and new experimental results and has

under conditions typical for those applications.

been applied to both petrol coke as a reference and bio-

The layer model accurately predicts the conversion be-

La Metallurgia Italiana - Luglio-Agosto 2026

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Industry news - Attualità industriale

haviour of both biogenic and fossil coals. Key findings in-

By establishing quantitative relationships among key ma-

clude:

terial parameters (density, volatile content, specific sur-

•

Particle density and diameter are primary influencing

face area, pore size) and conversion kinetics, the study

factors on conversion time; lower density and smaller

offers a rational basis for selecting and optimizing biochar

diameter accelerate conversion.

for industrial applications. The findings provide action-

Specific surface area and pore size exhibit compen-

able guidelines for the production and pre-treatment of

satory effects; increased surface area can be offset by

biochar tailored to EAF injection, supporting decarbon-

reduced pore diameter due to diffusion limitations.

ization strategies in steelmaking. First successful trials

High volatile content in biochar is disadvantageous

with tailored biochar show that the findings can be trans-

for EAF use, as volatiles are rapidly released and do

ferred to industrial operations.

not contribute to slag foaming.

The validated modelling framework can be extended

The model supports the definition of optimal particle

to other high-temperature applications, facilitating the

size and density for each type of biochar, ensuring

broader adoption of renewable carbon sources in the

comparable performance to fossil coal in EAF opera-

metallurgical sector.

•

tion regarding slag foaming.

REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

Ahmed, H., New trends in the application of carbon-bearing materials in blast furnace iron making. Minerals, 2018, 8, 561 Feliciano-Bruzual, C., Charcoal injection in blast furnaces (Bio-PCI): CO2 reduction potential and economic prospects. Journal of Materials Research and Technology, 2014, 3, 233-243 Suopajärvi, H. et al. Use of biomass in integrated steelmaking - Status quo, future needs and comparison to other low-CO2 steel production technologies. Applied Energy, 2013, 213, 384-407 Fick, G. et al. Using biomass for pig iron production: a technical, environmental and economical assessment. Waste and Biomass Valorization, 2014, 5, 1, 43-55 Bianco, L. et al. Sustainable EAF steel production (GREENEAF), Final Report. European Commission, Directorate-General for Research and Innovation, ISBN 978-92-79-33614-0 (2013) Cirili, F. et al. Biochar for a sustainable EAF steel production (GREENEAF2) – Final Report. European Commission, DirectorateGeneral for Research and Innovation, ISBN 978-92-79-98291-0 (2018) R. Mehrabian, S. Zahirovic, R. Scharler, I. Obernberger, S. Kleditzsch, S. Wirtz, V. Scherer, H. Lu, L.L. Baxter, A CFD model for thermal conversion of thermally thick biomass particles, Fuel Process. Technol. (2012). E.T. Turkdogan, J. V. Vinters, Effect of carbon monoxide on the rate of oxidation of charcoal, graphite and coke in carbon dioxide, Carbon N. Y. 8 (1970) 39–53. R.H. Tien, E.T. Turkdogan, Incomplete pore diffusion effect on internal burning of carbon, Carbon N. Y. 8 (1970) 607–621. M.P. King, Carbon injection into electric arc furnace slags, Master Thesis, McMaster University, 2009.

TORNA ALL'INDICE >

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Attualità industriale - Industry news

DOI 10.36146/2026_0708_36

Circular carbon and electrified heat: carbon neutral syngas heated by Paul Wurth Tempra to reduce blast furnace CO2 emissions L. Micheletti, C. Castagnola, A. Olcese, M. Venturini

Decarbonizing existing blast furnaces (BFs) is a central challenge for integrated steel producers pursuing climate neutrality while preserving asset value and production continuity. This paper presents an integrated, retrofit focused pathway combining Paul Wurth EASyRedgas: thermal dry reforming of coke plant by products with the Paul Wurth Tempra electric gas heating system, implemented within a Top Gas Recycling (TGR) configuration with CO2 removal. The approach converts internal carbonaceous waste streams into a high-quality syngas feed, electrifies the high temperature conditioning of that gas, and enables staged incorporation of hydrogen and CO2 management to achieve significant Scope 1 CO2 reductions with limited CAPEX risk and competitive OPEX. The anticipated benefits of retrofitting this technology into existing BF-based integrated plants are substantial. By incorporating this method into the decarbonization roadmap, plants can achieve a marked decrease in carbon emissions, contributing to a more sustainable steel production. The paper will detail the results obtained so far and outline the expected future outcomes, emphasizing the role of this technology in the industry's transition towards greener practices. This paper highlights a crucial step in the decarbonization of steel production, offering a cost-effective solution that aligns with global sustainability goals.

KEYWORDS: BLAST FURNACE; CO2; CIRCULAR CARBON; SYNGAS. FOREWORD Blast furnace (BF)-based steelmaking remains the dominant route for primary steel production, driven by high productivity, flexible iron ore sourcing, stable hot metal quality, and energy self sufficiency enabled by coal derived by product gases. Modern blast furnaces routinely achieve production levels of 4.5-5.0 MTPA with competitive operating costs, particularly in regions without CO 2 taxation. At the same time, the BF route faces increasing pressure due to its relatively high carbon footprint, which depends on raw material quality and operational efficien-

Lorenzo Micheletti, Cristiano Castagnola, Alessandro Olcese, Marco Venturini SMS group, Italy

cy. Reducing CO 2 emissions while preserving the intrinsic advantages of blast furnace ironmaking is therefore a key challenge for integrated steel producers. RATIONALE FOR THE EASYREDGAS TECHNOLOGY DEVELOPMENT Coke remains an unavoidable carbon source in the BF process, making the integration between coke making La Metallurgia Italiana - Luglio-Agosto 2026

pagina 36

Industry news - Attualità industriale and ironmaking central to any decarbonization strategy.

agglomeration routes. These trends favor coordinated

Coke plants generate three major carbon bearing by prod-

reuse of coke plant by products within the blast furnace

ucts: coke oven gas (COG), coal tar and coke fines. COG,

process.

rich in H₂ and CH₄, has traditionally been used as a fuel in reheating furnaces and captive power plants, but its avail-

EASYREDGAS CONCEPT

ability for metallurgical use is increasing as alternative

To address this opportunity, SMS developed Paul Wurth

fuels emerge and renewable electricity replaces internal

EASyRedgas technology [1], which converts COG togeth-

power generation. Coal tar faces declining market poten-

er with coke plant residues (coal tar and/or coke fines)

tial due to regulatory constraints, while coke fines—un-

into a hot reducing gas (See figure 1).

suitable for direct BF charging—are increasingly surplus due to declining sinter capacity and emerging alternative

Fig.1 - Concept of the EASyRedgas technology. The process is based on high‑temperature thermal dry

tion (see figure 2). Thermal Reforming removes heavy

reforming, using mainly CO₂ generated by oxy‑combus-

hydrocarbons and suppresses soot formation, enabling

tion of recycled by‑products to reform hydrocarbons into

injection at temperatures comparable to the ones exist-

a syngas rich in CO and H₂. The resulting syngas is suit-

ing lower BF shaft (900-1000 °C) without disturbing the

able for direct injection into the BF shaft or tuyeres, with

thermal balance of the BF shaft, once the syngas stream is

shaft injection identified as the preferred retrofit op-

mixed with cold BF gas or BOF gas.

Fig.2 - Process scheme of EASYREDGAS.

La Metallurgia Italiana - July-August 2026

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Attualità industriale - Industry news EASYREDGAS TECHNOLOGY VALIDATION

tinctive features. It utilizes input streams already available

Following process modeling and thermodynamic assess-

within the plant enabling energy and resource autarky for

ment, SMS group designed and operated an industrial

the adopting steelworks. A further advantage is input ma-

pilot plant to validate the technology. Pilot campaigns

terial flexibility enabled by material balance neutrality:

conducted in 2024 ITALIANA COKE industrial coke oven

when coal tar or coke fines are profitably sold on the mar-

plant Italy demonstrated stable production of hot syngas

ket EASyRedgas can replace them with external carbon

with suitable composition and temperature, refractory in-

sources in equivalent amounts without affecting the over-

tegrity of the reactor, and no significant soot formation us-

all CO₂ balance thus keeping its decarbonization poten-

ing industrially produced COG and COAL TAR. Thanks to

tial. The hot syngas produced is suitable for BF shaft in-

these results, EASyRedgas reached Technology Readi-

jection in terms of temperature and composition ensuring

ness Level 6 (TRL 6), confirming its suitability for industri-

a reduction in coke rate implying and a net CO2 emission

al application under realistic operating conditions [1].

decrease of approximately 7%. Finally, the industrial design features a limited footprint achievable through a ver-

EASYREDGAS APPLIED TO BLAST FURNACE DECAR‑

tical arrangement, making it suitable as an add-on retrofit

BONIZATION

for existing BFs which often have congested layout.

EASyRedgas can play a key role in the decarbonization of the BF based steel production route, due to several dis-

Fig.3 - EASyRedgas as first step for BF decarbonization.

EASYREDGAS WITH PAUL WURTH TEMPRA IN A

pra has unique technical features: It is scalable, up to 30

TOP GAS RECYCLING BF

to 40 MW per unit, highly efficient, with 97% energy ef-

Figure 3 illustrates the potential CO₂ reduction through

ficiency proven in a 0.5 MW pilot plant operated for over

BF shaft syngas injection using EASyRedgas as an add on

1000 hrs in the RINA CSM test center in Castel Romano

technology. To further advance BF decarbonization, pro-

(Italy) (figure 4); versatile, as it can work with multiple gas-

cess electrification must take center stage. In response SMS

es (hydrogen, air, steam and various combination of CO,

has developed Paul Wurth Tempra, an electric gas heating

CO2 H2, N2 and H2O) and supports process stability, thanks

technology enabling high efficiency, fossil-free heating

to a robust response to process fluctuations.

for the next Blast Furnace decarbonization step where recycled top gas must be heated above 1000°C. Tem-

La Metallurgia Italiana - Luglio-Agosto 2026

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Industry news - Attualità industriale

Fig.4 - TEMPRA Pilot Plant in Castel Romano (Italy). If Tempra and EASyRedgas are combined in a top gas re-

top gas is removed in a dedicated unit, the resulting pro-

cycling BF configuration where CO2 in the recirculated

cess scheme is shown in figure 5.

Fig.5 - Electrically heated -Top Gas Recycling BF: E-TGR BF with EASyRedgas. The denomination E-TGR stands for Electrically Heat-

ly on in plant energy sources and electricity.

ed Top Gas Recycling and derives from the adoption of

RE-PURPOSING OF EXISTING BF ASSETS BY MEANS

Tempra in the gas heating stage. In this scheme, oxygen

OF TEMPRA TO INCREASE COST EFFICIEN-CY

is used instead of hot blast, avoiding high nitrogen con-

In a Top Gas Recycling BF configuration with Tempra as

tent in the recirculated gas to improve process efficiency.

recirculated gas heater, the existing hot stoves—used

Tempra enables direct electrification of gas heating, so

for Blast heating in conventional BFs—becomes redun-

the BF top gas is no longer consumed in hot stoves. The

dant in the process loop shown in figure 5. These units

coke rate is reduced to 196 kg/tHM with PCI of 120 kg/

can therefore be re-purposed as Thermal Energy Storage

tHM.

(TES) enabling a cost efficient of time-dependent renew-

With this setup, CO₂ emissions drop by 30%, keeping

able electricity, from captive wind and solar sources. Le-

the delivered energy through internal gases to the inter-

veraging its long-standing BF expertise, SMS group has

nal users at the required amount. This step demonstrates

verified that the existing hot stoves, when operated as re-

how the combination of circular carbon, advanced elec-

generative heat exchangers, provide sufficient capacity to

trification, and efficient gas management delivers a major

store 10-12 hours of energy required to meet process gas

reduction in CO₂ emissions from a BF plant, relying sole-

heating demand in the configuration of figure 5. Coupling

La Metallurgia Italiana - July-August 2026

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Attualità industriale - Industry news Tempra as the renewable electricity based heat source

cess running efficiently though a proprietary gas -gas heat

with repurposed hot stoves as TES, results in a cost effi-

exchanger. This approach keeps a CO₂ reduction of ap-

cient gas heating system that exploits day-night electrici-

prox. 30% while delivering significant OPEX savings low-

ty price variations.

ering electricity cost. Re-tasking hot stoves to TES, makes

Figure 6 shows the two operating modes: on the left,

decarbonization practical and cost-effective for existing

during periods of low-cost renewable power, energy is

BFs, supporting efficient and process continuous electri-

stored in repurposed hot stoves; on the right, when elec-

fication through renewable power.

tricity prices rise, the stored heat is used to keep the pro-

Fig.6 - E-TGR with TES (Thermal Energy Storage) by Hot Stoves. FURTHER STEPS TO DECREASE CO2 EMISSIONS FROM

up while maintaining the configuration of fig-ure 5 stays

EXISTING BF

achieving a CO₂ reduction of 63% compared to the ref-

Figure 7 presents two alternative pathways for further de-

erence case. This option depends on the availability of af-

carbonization once the process scheme of figure 5 and 6

fordable, scalable green hydrogen and offers flexibility for

is applied. On the left, deep CO₂ reduction is enabled by

deep emission cuts as market conditions evolve. Residu-

adding CO₂ storage to the already foreseen CO₂ remov-

al CO₂ emissions are linked to the need to supply part of

al unit, dropping emissions to 69% below the reference

the top gas to auxiliary units such as coke oven plants and

case. A key enabler is the plasma torch, which superheats

reheating furnaces: a key criterion for benchmarking CO₂

the reducing gas and allows further coke savings. This

emissions calculations across technologies in integrated

technology is a core element of Paul Wurth EASyMelt

steel plants. The energy needs of main users must be ac-

platform now under industrialization by SMS group, with

counted for a correct evaluation of effective decarboniza-

Tata Steel has recently announced its application in a Blast

tion potentials on existing BF based plants.

Furnace in India. Full implementation of this scheme depends on CCUS infrastructure and market readiness, while the technical pathway is already established. On the right, green hydrogen is added to the gas loop as make-

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 40

Industry news - Attualità industriale

Fig.7 - Further steps for BF decarbonization (CCUS or green Hydrogen use). ANALYSIS OF OPERATING COST FOR EASYREDGAS

100 €/MWh. As indicated by the dotted lines, combining

AND TEMPRA BASED BF DECARBONIZATION

Tempra and Thermal Energy Storage using repurposed

Based on the raw materials and utilities costs listed in ta-

hot stoves doubles the OPEX savings to approximately

ble 1, SMS used proprietary process models to evaluate

40 €/tHM, demonstrating the effectiveness of exploiting

the operating costs of the configurations shown in fig-

renewable electricity price variability. Deeper decarbon-

ures 3-7. Figure 8 shows CO₂ emissions re-duction on

ization and further OPEX gains depend on the availability

the horizontal axis and OPEX variation on the vertical

of CO₂ storage or affordable green hydrogen. Figure 8

axis starting from the reference case of figure 3 for each

shows that the proposed roadmap enables cost-effective

BF decarbonization step. Up to step 2, the roadmap is

BF decarbonization already in the short term with a 30%

OPEX friendly under short term, representative cost as-

CO₂ reduction and paves the way for higher reductions

sumptions, achieving savings of about 20 €/tHM while

as boundary conditions are satisfied.

reducing the CO₂ emissions by 30% at a power cost of Tab.1 - Raw materials and utility costs for OPEX calculation.

La Metallurgia Italiana - July-August 2026

pagina 41

Attualità industriale - Industry news

Fig.8 - OPEX evolution throughout the proposed BF decarbonization steps.

CONCLUDING REMARKS AND FUTURE OUTLOOK

for sequencing implementation at integrated steel plants.

In conclusion, the integrated EASyRedgas - Tempra solu-

EASyRedgas technology is now ready to be tested in con-

tion offers a pragmatic, scalable retrofit pathway to signifi-

nection with a BF unit to prove its effectiveness in de-

cantly reduce BF Scope 1 CO₂ emissions while preserving

livering the coke rate reduction anticipated by process

productivity and limiting capital exposure.

calculations. SMS group is ready to cooperate with BF

By valorizing coke plant by-products into syngas, elec-

customers to advance the technology to TRL 8 in joint in-

trifying high temperature gas heating, and enabling pro-

dustrialization projects. This would represent a strategic

gressive hydrogen and CO₂ management, the concept

opportunity for those plants having relatively recently in-

accelerates the transition toward low carbon ironmaking

stalled BF units to avoid them becoming stranded assets

in existing BF based integrated plants. The paper present-

in view of the forthcoming decarbonization policies and

ed detailed energy and mass balances with ISO compliant

CO2 emissions taxation schemes.

CO₂ emission calculations, techno-economic comparisons across deployment stages, and recommendations

REFERENCES [1]

Innovative Decarbonization strategies: thermal dry reforming for enhanced Blast Furnace efficien-cy. Lorenzo Micheletti, Fabio Cravino, Cristiano Castagnola, Ilaria Dagna. 7th ESTAD 2025 – Verona (Italy) Proceedings.

TORNA ALL'INDICE >

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 42

edizione 2026

L’ing. Carlo Longaretti è nato il 17 novembre 1924 e la sua vita professionale rappresenta un’esperienza emblematica di interazione tra mondo della ricerca e produzione industriale. E’ stato ricercatore universitario, rappresentante italiano presso la Comunità Europea del Carbone e dell’Acciaio per la gestione dei progetti di ricerca, fu il primo ad introdurre in Italia la produzione e l’utilizzo delle ghise sferoidali e nel 1952 con il cugino Amanzio è stato fondatore della FGS, la fonderia di acciai e ghise speciali sita in Treviglio, tuttora attiva, che ha amministrato sino alla morte avvenuta il 29 marzo 2019. Carlo Longaretti è stata una persona determinata e geniale, in grado di integrare nel proprio lavoro le competenze elettrotecniche, strutturali e metallurgiche attraverso le quali ha sviluppato impianti fusori, tecnologie di solidificazione e nuove leghe per la resistenza alle alte temperature. Grazie alla sua generosità e a quella della famiglia, per ricordare una delle più insigni figure che si sono stagliate nel panorama dell’industria metallurgica italiana del XX e XXI secolo, l’AIM istituisce il Premio Carlo Longaretti. Il Premio, nella sua terza edizione, verrà conferito in occasione dell’International Workshop Carlo Longaretti 2026 a Bergamo il 3 dicembre 2026 ed include un contributo di €50.000 per sostenere il vincitore nello sviluppo della propria innovazione. L’oggetto dell’innovazione proposta per il concorso può essere un nuovo materiale di natura metallica, oppure un nuovo materiale anche non metallico che abbia un impatto positivo nella produzione o nell’applicazione delle leghe metalliche oppure una nuova tecnologia metallurgica o a servizio del settore metallurgico.

Come concorrere Il concorso per il premio è rivolto ai Soci AIM (a titolo personale o aziendale) e aperto a diplomati che abbiano frequentato o stiano frequentando un Istituto Tecnico Superiore, studenti di corsi di laurea, laureati, laureati magistrali, dottori di ricerca che dovranno presentare in lingua italiana o inglese: • curriculum vitae; • una descrizione dettagliata dal punto di vista tecnico e scientifico dell’innovazione proposta (massimo 15 pagine), che includa: - elementi che validino l’innovazione e che escludano che si tratti di un’idea di carattere teorico senza prospettive concrete di sviluppo (es. dati sperimentali anche su scala ridotta, immagini, filmati ecc.). - elementi che comprovino l’originalità dell’innovazione proposta; - elementi che indichino quali esigenze intenda soddisfare la propria innovazione e quale è l’impatto atteso; • lista delle proprie pubblicazioni, in particolare di quelle relative all’innovazione proposta. Il termine di presentazione delle domande, da trasmettersi per email (info@aimnet.it) alla Segreteria AIM, è fissato al 15 ottobre 2026.

�946 2026

Via F. Turati 8 . Milano t. +39 0276397770 / +39 0276021132 info@aimnet.it . www.aimnet.it

PREMIO

Bando Premio Carlo Longaretti

Attualità industriale - Industry news

DOI 10.36146/2026_0708_44

Ecological assessment of the use of hydrochar in EAF operation based on an LCA approach C. Gondorf, F. Kaiser, T. Echterhof

The environmental impacts associated with using hydrochar in electric arc furnace (EAF) steelmaking were evaluated using a life cycle assessment (LCA). The goal is to quantify potential environmental impacts and identify key drivers and trade-offs when hydrochar substitutes conventional fossil carbon in EAF practice. The LCA follows ISO 14040/14044 principles, applying a functional unit of “1 tonne of liquid steel produced in an EAF” and comparing a baseline fossil-carbon scenario with multiple hydrochar integration scenarios. Impact categories include climate change, particulate matter formation, terrestrial acidification, water eutrophication, resource use, and water-related indicators. Results indicate that hydrochar can meaningfully reduce fossil carbon demand and associated greenhouse gas emissions, particularly when produced from residue streams with low upstream burdens and when HTC/drying energy is supplied by low-carbon sources or recovered heat. However, benefits may be offset by higher processing energy, increased ash handling, and potential trade-offs in terrestrial acidification/water eutrophication depending on feedstock cultivation and nutrient emissions. Hotspots typically include energy for dewatering/drying and the electricity mix, making decarbonized energy supply and process integration critical. The study provides guidance on environmentally robust hydrochar supply chains and operational conditions under which hydrochar contributes to lower-impact EAF steelmaking.

KEYWORDS: HYDROCHAR; EAF STEELMAKING; LIFE CYCLE ASSESSMENT; CARBON CARRIERS SUBSTITUTION; SUSTAINABILITY; ORGANIC RESIDUALS. INTRODUCTION Electric Arc Furnaces (EAFs) rely on carbonaceous materials (e.g., anthracite, coke breeze, or synthetic graphite) for slag foaming, oxygen refining, and energy efficiency. Replacing fossil-derived carbon with hydrochar, produced via hydrothermal carbonization (HTC) of biomasses or residues, could lower the environmental footprint of steelmaking. Yet the net benefit depends strongly on feedstock origin, process energy, and operational substitution rates. This study presents an ecological assessment of hydrochar use in EAF operation based on a life

Carsten Gondorf, Felix Kaiser, Thomas Echterhof RWTH Aachen University, Germany

cycle assessment (LCA) framework. LCA is a standardized method for quantifying and assessing the environmental burdens of product systems across defined system boundaries. It is widely applied by industry, policy makers, and environmental organizations to support environmental strategy development and informed material

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 44

Industry news - Attualità industriale selection; accordingly, it provides a suitable framework

The assessment distinguishes between integrated and

for assessing hydrochar substitution in EAF operation (1).

non-integrated hydrochar production and investigates two EAF substitution pathways: replacing fossil carbon

Following ISO EN 14040 and ISO EN 14044, a systematic

with fine-grained hydrochar for injection, and replacing

data collection and transparent reporting of results were

fossil charged carbon with hydrochar agglomerates. For

implemented. This structured approach enables the iden-

each pathway, the substitution rate of 100% biogenic car-

tification of potential hotspots and previously overlooked

bon in therms of hydrochar instead of fossile carbon was

weaknesses along the process chain, thereby highlight-

investigated.

ing optimization opportunities (2, 3). First, the goal and

The Hydrochar, a carbon-rich solid fuel, was produced via

scope of the LCA were defined. Subsequently, a life cycle

hydrothermal carbonisation (HTC). The process is per-

inventory (LCI) was compiled by identifying and quantify-

formed under oxygen-free conditions in subcritical liquid

ing the key material and energy flows within the system.

water, increasing the carbon content of the solid product

A material flow model was developed, including data

through reactions such as hydrolysis, dehydration, de-

collection, allocation choices, calculation of FU-related

carboxylation, aromatisation, and recondensation (4). A

material flows, and the derivation of emissions and other

key advantage of HTC is that it can process high-moisture

relevant operating parameters. Based on the inventory,

feedstocks while still achieving high yields and a relatively

the life cycle impact assessment (LCIA) quantified the en-

high heating value of the resulting hydrochar (5, 6). The

vironmental impacts. In the interpretation phase, system

core unit is a heated, pressurised stirred reactor, operat-

boundaries and material flows were critically checked and

ed under inert conditions via nitrogen purging and moni-

validated, and results were evaluated for consistency and

tored by temperature and pressure control. Table 1 shows

robustness. All assumptions, methodological steps, and

the evaluation of utilising hydrochar produced from or-

result visualizations were documented.

ganic residues.

Tab.1 - Evaluation of utilising hydrochar produced from organic residues (7). Sample

Moisture

Volatile

Ash

Fixed C

Lingyuan anthracite

77.38

3.61

0.86

0.90

0.84

13.21

15.02

70.93

1.35

Shenhua bituminous coal

65.12

4.05

0.92

0.34

5.05

35.88

8.58

49.49

15.94

Hydrochar from green waste

50.94

4.95

1.43

0.38

2.58

57.82

15.97

23.63

23.75

Hydrochar from organic fraction

58.61

6.72

2.24

0.31

2.11

68.76

12.88

16.25

17.13

Hydrochar from orange peel

58.06

5.08

1.56

0.16

3.51

59.66

6.18

30.65

25.45

LCA Goal and scope definition

(FEP), Human Toxicity Potential (HTP), Metal Depletion

The study compares fossil-based and biogenic carbon car-

Potential (MDP), Natural Land Transformation Potential

riers by assessing the substitution of conventional carbon

(NLTP), Ozone Depletion Potential (ODP), Photochemical

inputs with hydrochar in EAF steelmaking. Environmental

Oxidant Formation Potential (POFP), Terrestrial Acidifica-

impacts were quantified using the ReCiPe Midpoint meth-

tion Potential (TAP), and Water Use (WU). The modelling

od. The evaluated impact indicators comprise Global

focuses on the EAF melting stage, while additionally ac-

Warming Potential (GWP, climate change), Fossil Deple-

counting for relevant upstream and downstream process-

tion Potential (FDP), Freshwater Eutrophication Potential

es to ensure a consistent comparison across cases. The

La Metallurgia Italiana - July-August 2026

pagina 45

Attualità industriale - Industry news functional unit (FU) is defined as 1 tonne of liquid tapped

Inventory analysis and calculation of environmental

steel, and the system boundary is set according to a gate-

impacts

to-gate approach (8, 3).

The life cycle inventory (LCI) comprises the collection and calculation of primary data in close collaboration with

For this study, plant-specific operating data were collect-

industrial partners, which were subsequently implement-

ed, aligned, and analyzed. In collaboration with two steel

ed in the LCA process models. To ensure consistent and

plant, two site-specific baseline LCA models were estab-

comprehensive data acquisition, a standardized check-

lished. The work started with a goal and scope definition

list for electric steelmaking process data was developed,

tailored to the intended application and iteratively refined

derived from a generic EAF mass balance. Based on this

during model development. The overall aim is to compare

framework, all relevant material and energy inputs as well

the environmental performance of alternative process

as outputs associated with the EAF melting stage were

routes at the partner sites. For each scenario, the neces-

identified and considered (figure 1 (l)). Modelling and

sary process parameters were compiled. Remaining data

impact calculations were performed in Umberto® LCA+

gaps were addressed through transparent and well-justi-

using datasets from ecoinvent®; figure 1 (r) illustrates the

fied assumptions.

corresponding model structure for the base case for an EAF operation.

Fig.1 - General mass balance (l) and General LCA process model in Umberto® LCA+®. To comply with confidentiality requirements, the LCI is in-

The principal change between scenarios is the substitution

terpreted in relative terms rather than reporting site-spe-

of fossil carbon by hydrochar, differentiated by applica-

cific values. Across both plants, the substitution concept

tion route, one case targets injected carbon and the other

is implemented without changing the overall production

targets charged carbon. Due to the assumed fixed-car-

function (1 t liquid tapped steel as functional unit) and with

bon content of hydrochar, the required hydrochar mass

essentially constant major operating parameters such

per functional unit is higher than the corresponding fos-

as electricity demand (approximately 410 – 420 kWh per

sil-carbon mass to provide an equivalent fixed-carbon

tonne of steel), electrode consumption, flux addition and

function. In the inventories, this manifests as an increase

scrap charge. This indicates that the compared cases are

from about 7.0 – 7.3 kg/t fossil carbon to about 10.6 – 10.9

designed to isolate the effect of the carbon carrier change

kg/t hydrochar. Aside from this substitution, no system-

while keeping the core EAF operation comparable.

atic shifts in auxiliary inputs are visible, suggesting that

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Industry news - Attualità industriale the modelling isolates carbon-carrier effects rather than

substitution of fossil-derived carbon by biogenic fixed

attributing major operational changes to hydrochar use at

carbon, rather than by changes in the EAF mass balance or

the foreground level.

main operating consumptions.

On the output side, liquid steel production is fixed at 1

Table 2 summarizes the LCI for the hydrochar production

t (FU), while by-products and process-related flows re-

via HTC per tonne of biowaste input. For the subsequent

main consistent across scenarios, including dust gener-

LCIA, mean inventory values were derived and applied as

ation and slag. This inventory structure implies that dif-

representative inputs to the model. In addition, a feed-

ferences observed in the subsequent impact assessment

stock sensitivity analysis was performed to assess the in-

are expected to be driven primarily by upstream burdens

fluence of biomass variability on the results and to identify

of hydrochar production and logistics, the electricity and

potential hotspots as well as optimization opportunities

heat supply assumed for HTC and post-treatment, and the

associated with different biowaste types.

Tab.2 - LCI per ton of biowaste (Units refer to: dw - dry weight basis) (9). Category

Input

Output

Inputs & Outputs

Units

Green Waste

Food Waste

Organic fraction of MSC

Digestate

Waste

ton (dw)

Moisture content

Electricity for pumping

kWh

0.003

Thermal Energy

kWh

611.1

Electricity for drying & pelletizing

kWh

Electricity for reverse osmosis

kWh

0.54

0.37

0.62

0.56

Raw hydrochar

ton (dw)

0.59

0.37

0.72

0.56

Cleaned hydrochar pellets

ton (dw)

0.54

0.37

0.62

0.56

Process waster

ton

0.5597

0.8543

0.4714

0.6678

Ash

ton

0.0703

0.0179

0.1011

0.0597

N in waste stream

ton

0.0011

0.0017

0.0008

0.0013

P in waste stream

ton

0.0001

K in waste stream

ton

0.0002

0.0008

0.0005

0.0009

Carbon dioxide (CO2)

ton

0.0624

0.0434

0.0257

0.0118

Carbon monoxide (CO)

ton

0.0006

0.0004

0.0006

Hydrogen (H2)

ton

0.0001

0.0009

Regarding the process data of steel plant A, three scenarios with two different cases (production with energy mix and production with green energy mix) were investigated:

•

Scenario 1: 100 % fossil carbon injection

La Metallurgia Italiana - July-August 2026

• •

Scenario 2: 100 % hydrochar for injection (external production) Scenario 3: 100 % hydrochar for injection (internal production)

pagina 47

Attualità industriale - Industry news Table 3 presents a contribution analysis (normalized to

Under renewable electricity, the contribution of electric

100% per impact category) for the EAF in case A. With the

power decreases significantly for GWP and most air-re-

current mix, environmental burdens are largely driven by

lated categories, and off-gas becomes negligible across

electric power and EAF off-gas. Electric power contrib-

indicators. As a result, consumables and utilities gain rel-

utes strongly to climate change (42% GWP) and dominates

ative importance: oxygen dominates water use (65.3%),

fossil depletion (56% FDP) and freshwater eutrophication

while natural gas and fossil carbon become more relevant

(77.1% FEP), while also being relevant for ozone deple-

for fossil depletion. Electric power still contributes sub-

tion, photochemical oxidant formation, terrestrial acidi-

stantially to metal depletion (49.1%), indicating that this

fication, and water use. EAF off-gas is the main hotspot

category is influenced by upstream material requirements

for human toxicity (86.1% HTP), metal depletion (70.8%

of the electricity system.

MDP), and natural land transformation (89.4% NLT), and remains a major contributor to photochemical oxidant formation and terrestrial acidification. Tab.3 - LCIA of steel plant A (Production with energy mix, Scenario 1). Result of the impact assessment Medium

GWP 100 [%]

FDP [%]

FEP [%]

HTP inf [%]

MDP [%]

NLTP [%]

ODP inf [%]

POFP [%]

TAP 100 [%]

WU [%]

Production with energy mix, Scenario 1 Electric power

42.0

56.0

77.1

13.1

28.0

7.3

56.6

29.2

42.1

32.1

Electrode consumption

0.4

1.3

0.1

0.2

0.1

0.2

2.1

0.4

0.6

0.2

Oxygen

0.0

0.1

0.0

50.0

Natural gas

0.2

5.9

0.1

0.0

0.1

0.0

0.1

0.2

0.1

Fossil carbon

0.8

4.5

6.1

0.1

0.3

2.5

0.4

1.8

2.5

0.3

Polymer

0.3

0.2

0.3

0.2

0.1

0.3

0.2

Lime

10.9

3.5

0.3

0.5

0.3

6.1

3.5

2.8

1.9

EAF offgas

45.5

28.6

16.0

86.1

70.8

89.4

34.6

64.6

51.6

15.2

Production with renewable energy, Scenario 1 Electric power

7.1

8.5

24.1

20.9

49.1

7.6

6.9

9.6

17.5

11.4

Electrode consumption

0.6

2.7

0.4

0.1

0.2

4.5

0.6

0.9

0.3

Oxygen

0.0

0.1

0.0

0.1

0.0

65.3

Natural gas

0.3

12.3

0.2

0.0

0.1

0.0

0.1

0.3

0.2

0.1

Fossil carbon

1.3

9.3

20.2

0.1

0.2

2.5

0.9

2.3

3.5

0.4

Polymer

0.4

0.5

1.0

0.1

0.2

0.3

0.4

0.2

Lime

17.5

7.3

0.8

0.3

13.0

4.5

4.0

2.4

EAF offgas

72.8

59.4

53.1

78.4

50.0

89.1

74.3

82.4

73.5

19.8

For the most relevant scenarios for the hydrochar pro-

TAP, reported as external and internal results for plant A in

duction, the impact category of Global Warming Poten-

Scenarios 2 and 3. With the current electricity mix, elec-

tial, Freshwater Eutrophication Potential and Terrestrial

tricity supply dominates FEP (about 78%) and contributes

Acidification Potential were used for further comparison.

around 42-43% to GWP and TAP, while EAF off-gas is the

Table 4 shows contribution shares for GWP, FEP, and

main hotspot for GWP (about 46%) and TAP (about 53%).

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 48

Industry news - Attualità industriale Lime remains a relevant contributor to GWP (about 11%).

tributor across all three indicators (roughly 55-76%). Lime

Charged hydrochar has only minor effects on GWP and

becomes more important for GWP (~18%). Charged hy-

TAP but contributes around 5% to FEP.

drochar becomes more visible in FEP (about 14-18%) while remaining small for GWP and TAP. Differences be-

With renewable electricity, the contribution of electric

tween external and internal splits are generally small, in-

power drops strongly (GWP ~7%, FEP ~25%, TAP ~18%),

dicating a stable hotspot ranking across accounting per-

and the profile shifts to EAF off-gas as the dominant con-

spectives.

Tab.4 - LCIA of steel plant A (Production with energy mix, Scenario 2 & 3). Medium

GWP 100 [%]

FEP [%]

TAP 100 [%]

External

Internal

External

Internal

External

Internal

Production with energy mix, Scenario 2 & 3 Electric power

42.1

42.2

77.7

78.0

43.0

Electrode consumption

0.4

0.1

0.6

Oxygen

0.0

Natural gas

0.2

0.1

Charged hydrochar

0.3

5.4

5.0

0.4

0.2

Polymer

0.3

Lime

11.0

0.3

2.9

EAF offgas

45.7

16.1

16.2

52.7

52.8

Production with renewable energy, Scenario 2 & 3 Electric power

7.2

24.7

26.0

18.1

18.2

Electrode consumption

0.6

0.4

0.5

0.9

Oxygen

0.0

0.1

0.0

Natural gas

0.3

0.2

Charged hydrochar

0.5

0.2

18.1

13.7

0.6

0.0

Polymer

0.4

1.1

0.4

Lime

17.6

17.7

0.9

4.1

EAF offgas

73.4

73.6

54.5

57.4

75.7

76.2

Regarding the process data of steel plant B, three scenar-

mainly driven by electric power and EAF off-gas. Electric

ios with two different cases (production with energy mix

power contributes substantially to climate change (44.0%

and production with green energy mix) were investigated:

GWP) and dominates fossil depletion (56.6% FDP) and

• • •

Scenario 1: 100 % fossil charged carbon

freshwater eutrophication (78.5% FEP); it is also relevant

Scenario 2: 100 % hydrochar carbon pellets (external

for ozone depletion (45.2%), photochemical oxidant for-

production)

mation (29.6%), terrestrial acidification (41.0%), and wa-

Scenario 3: 100 % hydrochar carbon pellets (internal

ter use (40.8%). EAF off-gas is the key hotspot for human

production)

toxicity (91.9% HTP), metal depletion (87.6% MDP), and natural land transformation (93.3% NLT), and contributes

Table 5 provides the contribution analysis for the EAF case

strongly to photochemical oxidant formation (65.9%) and

B (Scenario 1). Under the current mix, impacts are, again,

terrestrial acidification (54.1%). Oxygen supply is negli-

La Metallurgia Italiana - July-August 2026

pagina 49

Attualità industriale - Industry news gible for most categories but accounts for a large share

same time, terrestrial acidification shifts markedly: lime

of water use (42.7%). Lime shows a consistent secondary

becomes the main driver (78.2% TAP), while the off-gas

contribution, particularly to GWP (9.7%).

contribution drops to zero, indicating that the remaining acidification burden is largely associated with upstream

With renewable electricity, the contribution of electric

lime production rather than EAF emissions. Oxygen be-

power decreases strongly for climate change (6.5% GWP)

comes the primary driver of water use (67.9%). Overall,

and several air-related categories, but remains important

the results show that decarbonizing electricity changes

for metal depletion (41.6%) and still contributes to fresh-

the hotspot structure, reducing the role of power for cli-

water eutrophication (19.4%). In this case, EAF off-gas

mate change but increasing the relative importance of off-

becomes the dominant contributor for most categories,

gas and selected material inputs, underscoring the need

including GWP (73.6%), FDP (68.3%), FEP (58.1%), HTP

for multi-indicator mitigation strategies.

(83.0%), NLT (91.2%), and ozone depletion (78.0%). At the Tab.5 - LCIA of steelplant B (Production with energy mix, Scenario 1). Result of the impact assessment Medium

GWP 100 [%]

FDP [%]

FEP [%]

HTP inf [%]

MDP [%]

NLTP [%]

ODP inf [%]

POFP [%]

TAP 100 [%]

WU [%]

Production with energy mix, Scenario 1 Electric power

44.0

56.6

78.5

7.5

11.5

4.1

45.2

29.6

41.0

40.8

Electrode consumption

0.4

1.3

0.1

0.2

2.4

0.4

0.6

0.2

Oxygen

0.0

0.1

0.0

42.7

Natural gas

0.1

1.9

0.0

0.1

0.0

Fossil carbon

0.8

4.3

5.1

0.1

0.3

2.2

0.5

1.5

2.2

0.3

Lime

9.7

2.9

0.2

0.3

0.4

0.2

5.7

2.5

2.0

1.3

EAF offgas

45.0

33.1

16.0

91.9

87.6

93.3

46.2

65.9

54.1

14.7

Production with renewable energy, Scenario 1 Electric power

6.5

7.2

19.4

16.4

41.6

5.7

5.3

10.4

18.4

9.5

Electrode consumption

0.7

3.1

0.5

0.1

0.2

4.7

0.0

Oxygen

0.0

0.1

0.0

0.1

0.0

67.9

Natural gas

0.1

4.4

0.1

0.0

Fossil carbon

1.5

10.2

21.2

0.1

0.2

2.5

0.9

3.8

3.4

2.0

Lime

17.5

6.8

0.7

0.3

0.2

11.0

85.9

78.2

20.6

EAF offgas

73.6

68.3

58.1

83.0

57.7

91.2

78.0

0.0

Again, the impact categories of Global Warming Potential,

to GWP (about 45%) and accounts for the remaining share

Freshwater Eutrophication Potential and Terrestrial Acid-

in FEP and TAP (about 16% and 55%, respectively). Lime

ification Potential were used for further evaluation. Table

shows a noticeable contribution to GWP (~10%) and TAP

6 reports the contribution shares for plant B in Scenarios

(~2%). Charged hydrochar remains small for GWP and

2 and 3for the external and internal production of hydro-

TAP but contributes around 4-5% to FEP.

char. With the current electricity mix, electricity supply dominates FEP (about 79%) and contributes around 42-

Under renewable electricity, the contribution of electric

44% to GWP and TAP. EAF off-gas is the main contributor

power decreases markedly (GWP ~6-7%, FEP ~20-21%,

La Metallurgia Italiana - Luglio-Agosto 2026

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Industry news - Attualità industriale TAP ~19%). The remaining impacts are largely driven by

turn changes the impact results. The total climate-change

EAF off-gas for GWP (~74-75%) and FEP (~60-63%). In

impact of hydrochar production ranges from 73.6 to 110.4

contrast to case A, TAP shifts strongly to lime as the dom-

kg CO 2-eq per t biowaste (−18% to +23% relative to the

inant hotspot (around 80-81%), while off gas becomes

feedstock mean), with the highest value obtained for

negligible for TAP. Charged hydrochar becomes more

green waste, mainly driven by the CO2/phosphate-relat-

relevant for FEP (about 14-19%) but remains minor for

ed contribution (62.4 kg CO2-eq), whereas MSW shows

GWP and TAP.

the lowest total (25.7 kg CO 2-eq from CO 2/phosphates). Freshwater eutrophication exhibits the strongest relative

A feedstock sensitivity analysis was carried out by varying

sensitivity, varying from 0.020 to 0.100 kg P-eq (−72% to

the HTC input between four representative biowaste types

+40%); this spread is largely controlled by the CO2/phos-

(green waste, food waste, organic fraction of MSW, and

phate term (0.0018–0.083 kg P-eq), confirming that nutri-

digestate) while keeping the EAF substitution rate condi-

ent-related burdens of the liquid fraction dominate this

tions constant. The feedstocks differ primarily in moisture

indicator. Terrestrial acidification varies between 0.35 and

content (34-84% across the investigated wastes) and in

0.511 kg SO2-eq (−11% to +30%), with digestate showing

the associated upstream burdens of the process-water

the highest value, consistent with its comparatively higher

stream (CO 2/phosphate-related contributions), which in

electricity and thermal-energy contributions.

Tab.6 - LCIA of steelplant B (Production with energy mix, Scenario 2 & 3).

Medium

GWP 100 [%]

FEP [%]

TAP 100 [%]

External

Internal

External

Internal

External

Internal

Production with energy mix, Scenario 2 & 3 Electric power

44.2

79.1

79.3

41.8

41.9

Electrode consumption

0.4

0.1

0.6

Oxygen

0.0

Natural gas

0.1

0.0

Charged hydrochar

0.3

4.5

4.2

0.3

0.2

Lime

9.8

0.2

2.1

EAF offgas

45.2

16.1

16.2

55.2

55.3

Production with renewable energy, Scenario 2 & 3 Electric power

6.6

19.9

21.1

18.9

19.0

Electrode consumption

0.7

0.5

0.0

Oxygen

0.0

0.1

0.0

Natural gas

0.1

0.0

Charged hydrochar

0.6

0.3

19.0

14.4

0.6

0.0

Lime

17.7

0.8

80.5

81.0

EAF offgas

74.3

74.5

59.7

63.0

0.0

Interpretation and reporting on the LCA results

phication, while EAF off-gas dominates toxicity- and

Electricity is a key driver of climate change and the main

land-related indicators and contributes strongly to pho-

contributor to fossil depletion and freshwater eutro-

tochemical oxidant formation and terrestrial acidification.

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Attualità industriale - Industry news

Secondary contributors include lime (relevant to climate

current electricity mix. Electricity strongly drives climate

change and, in some cases, acidification) and oxygen sup-

change, fossil depletion, and freshwater eutrophication,

ply, which has limited influence on most categories but is

while off-gas is the main hotspot for toxicity- and land-re-

a major driver of water use. Switching to renewable elec-

lated categories and contributes substantially to photo-

tricity shifts the contribution profile. The share of electric

chemical oxidant formation and terrestrial acidification.

power decreases sharply for climate change and several

Oxygen and lime are relevant for specific indicators, es-

air-related categories; however, metal depletion remains

pecially water use and acidification. Hydrochar can con-

partly driven by electricity, indicating upstream material

tribute to reducing the environmental footprint of EAF

requirements in the electricity system. Under renewable

steelmaking, but benefits depend strongly on low-carbon

electricity, remaining burdens are increasingly governed

energy for hydrochar production and EAF electricity, as

by direct process emissions and consumables. The life

well as improved characterization of off-gas emissions.

cycle impact assessment confirms that substituting fossil

Further primary measurements and refined modelling of

carbon carriers with biogenic alternatives in EAF steel-

hydrochar supply chains (integrated vs. non-integrated)

making is technically feasible and can reduce the foot-

are recommended to reduce uncertainty and support ro-

print of different impact categories. However, for Scenar-

bust cross-category improvements.

ios 2 and 3, hydrochar substitution does not substantially change the overall hotspot ranking at plant level, because

Overall, process simulation via LCA provides a useful

electricity and off gas remain dominant. Charged hydro-

complement to industrial trials, enabling the analysis of

char contributes only marginally to climate change and

non-measurable variables and supporting targeted opti-

terrestrial acidification, but it is more relevant for freshwa-

mization of EAF operation. Extending this modelling ap-

ter eutrophication, especially under renewable electrici-

proach to other hydrochars could improve the efficien-

ty, where upstream burdens become more visible. Differ-

cy and focus of future industrial-scale testing. Previous

ences between internal and external results are generally

campaigns (e.g., GreenEAF2) further indicate elevated CO

small, and hotspot rankings remain stable, supporting the

and CO2 peaks as well as potentially higher N2, H2, H2O,

robustness of the qualitative interpretation. Uncertain-

and CH4 in the off-gas when biogenic carbon is applied,

ty is mainly associated with limited primary off-gas data

which should be considered in a holistic environmental

and background dataset choices for electricity and key

and operational comparison. Higher reactivity and vola-

inputs. Given the strong influence of off-gas and electric-

tile content of the biogenic carbon can increase average

ity, improved off-gas measurements and refined energy

CO and CO2 concentrations in the off-gas, highlighting

balances would significantly strengthen result validity.

the importance of off-gas related effects when assessing

Overall, the results indicate that robust environmental

overall performance in the upcoming industrial trials

improvements from hydrochar require not only fossil carbon substitution, but also low-impact hydrochar supply

ACKNOWLEDGEMENTS

chains and broader measures targeting electricity, off-gas

The authors gratefully acknowledge the financial support

management, and major consumables (notably oxygen

from EU RFCS BioReSteel project (grant no. 101112383).

and lime). CONFLICT OF INTEREST CONCLUSION

The authors declare no conflict of interest.

This study applied an ISO 14040/14044-compliant LCA to evaluate hydrochar as a substitute for fossil carbon carri-

AUTHOR CONTRIBUTIONS

ers in EAF steelmaking. Across plants and scenarios, the

Carsten Gondorf: conceptualization (lead); data curation

contribution analyses show that electricity supply and

(lead); investigation (lead); methodology (equal); writing

EAF off-gas dominate most impact categories under the

- original draft (lead).

La Metallurgia Italiana - Luglio-Agosto 2026

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Industry news - Attualità industriale

Felix Kaiser: conceptualization (equal); data curation (sup-

DATA AVAILABILITY STATEMENT

porting); writing - review and editing (supporting).

The data that support the findings of this study are avail-

Thomas Echterhof: funding acquisition (lead); project ad-

able from the corresponding author upon reasonable re-

ministration (lead); writing—review and editing

quest.

(supporting).

REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9]

World Steel Association. Life cycle assessment (LCA). DIN EN ISO 14044. Ökobilanz –Anforderungen und Anleitungen. Berlin; 2006. DIN EN ISO 14040. Ökobilanz –Grundsätze und Rahmenbedingungen. Berlin; 2006. Funke A, Ziegler F. Hydrothermal carbonization of biomass: A summary and discussion of chemical mechanisms for process engineering. In: Biofuels, Bioproducts and Biorefining 2010; (Vol. 4(2)) S. 160-177. Libra JA, Ro KS, al. CKe. Hydrothermal carbonization of biomass residuals: A comparative review of the chemistry, processes and applications of wet and dry pyrolysis. In: Biofuels, Bioproducts and Biorefining 2010; (Vol. 2(1)). Lucian M, Fiori L. Hydrothermal Carbonization of Waste Biomass: Process Design, Modeling, Energy Efficiency and Cost Analysis. In: Energies 2017; (Vol. 10(2)); S. 211. Hernandez M, Salimbeni A, Hitzl M, Zhang J, Wang G, Wang K et al. Evaluation of Utilising Ingelia Hydrochar Produced from Organic Residues for Blast Furnaces Injection - Comparison with Anthracite and Bituminous Coal; 2018. Klöpffer W, Grahl B. Ökobilanz (LCA)- Ein Leitfaden für Ausbildung und Beruf. Weinheim: WILEY- VCH Verlag; 2009. Owsianiak M, Ryberg MW, Renz M, Hitzl M, Hauschild MZ. Environmental Performance of Hydrothermal Carbonization of Four Wet Biomass Waste Streams at Industry-Relevant Scales. ACS Sustainable Chem. Eng. 2016; 4(12):6783–91.

TORNA ALL'INDICE >

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Attualità industriale - Industry news

DOI 10.36146/2026_0708_54

Renewable Carbon Integration in HIsarna Ironmaking Process N. Madhavan, N. Dogan, Y Yang, K. Meijer, J.L.T. Hage

HIsarna ironmaking is a breakthrough smelting reduction technology with the potential to reduce CO 2 emissions by 90% when using coal combined with CCS and negative CO 2 footprint when using biochar and CCS. This study evaluates biochar production integration to the HIsarna process operations from the perspective of raw ma-terial consumption, unit wise energy requirements, and by-product utilisation using a flowsheet modelling ap-proach. The model demonstrates a strong thermal synergy between the ironmaking and pyrolysis processes, with HIsarna off-gas heat recovery and recycled pyrogas collectively satisfying the thermal demand of continuous slow pyrolysis process. The economic evaluation shows that the integrated system is profitable and the profita-bility structurally governed by co-product markets particularly CO2 credits and bio-oil sales rather than biochar value itself.

KEYWORDS: HISARNA; SLOW PYROLYSIS; PROCESS INTEGRATION; DECARBONIZATION; METSIM, BIOCHAR. INTRODUCTION The HIsarna smelting reduction process is uniquely positioned for carbon-neutral ironmaking that facilitates 100% replacement of coal with biochar. Life Cycle Assessments confirm that HIsarna process operating with bio-based reductants can achieve net-negative emissions as low as -0.5 t CO 2/t steel [1], but these macro-level studies stop at system boundary definitions and aggregate mass flows. No prior work has been carried out on mass, energy, CO2, and economic balances of integration of possible on-site slow pyrolysis plant sized to the full biochar to meet the demand of a commercial 1 Mt/yr HIsarna facility. This work develops an integrated steadystate METSIM flowsheet simulation model bridging that gap. The comprehensive detail of modelling is described in the paper [2], and this paper presents the key functional performance indicators and strategic implications.

Nirmal Madhavan, Neslihan Dogan, Yongxiang Yang

Department of Materials Science and Engineering, Delft Universi-ty of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands

Koen Meijer, J.L.T. Hage

Tata Steel Netherlands Technology, Research & Development, 1970 CA IJmuiden, The Nether-lands

MODELLING METHODOLOGY A steady-state mass and energy balance model was developed with METSIM commercial software to simulate the integration of a slow pyrolysis biochar production plant with a commercial HIsarna ironmaking facility producing 1 Mt/yr of hot metal. The model is structured around three boundary input domains: the Biochar Production Plant (the primary unit under study), and its two

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 54

Industry news - Attualità industriale external supporting systems: HIsarna process data and

rect pyrolysis heating supplemented by recycled pyrogas.

power plant/utilities. While the HIsarna and power plant

KEY RESULTS

units provide the necessary energy inputs (sensible heat

System thermal synergy: Total process energy intensity

and electricity), they exist outside the specific biochar

is 7.2 GJ/t biochar. As shown in figure 1, thermal stages

production unit operations. The primary material outputs

(drying + pyrolysis) account for 90% of this demand which

are biochar, bio-oil, and biogas, and recovered heat. Unit

satisfied by HIsarna off-gas heat and recycled pyrogas.

operations in the flowsheet including drying, grinding, py-

Flowsheet heat balance is shown in table 1 for 83 t/h pro-

rolysis, heat exchange, and briquetting are considered for

duction of biochar integrated into HIsarna ironmaking.

continuous rotary slow pyrolysis kiln operating at 550°C, with HIsarna off-gas sensible heat at 900°C supplying indi-

Tab.1 - Heat balance of biochar production integrated to HIsarna.

ENERGY IN

Chemical energy in biomass

1357

Biochar energy

670

Heat from HIsarna gas

Bio-oil energy

367

Electricity (grind + briquet)

Biogas energy left

Recovered power

34.8

Pyrolysis + dryer loss

Other loss

244

Total energy input

1441

ENERGY OUT

Fig.1 - Process energy distribution by unit operation.

Cost and revenue analysis: Biomass procurement alone

(revenue minus expense) of 236 €/t of biochar, indicat-

consumes 60% of total raw material cost (figure 2(a)),

ing that the integrated system is profitable. The margin

confirming that feedstock supply chain risk, not energy

is therefore resilient to energy price swings but exposed

cost, is the dominant operational vulnerability. Figure 2(b)

to simultaneous adverse movements in bio-oil price and

shows that the profitability is structurally co-determined

carbon credit price, making revenue hedging the critical

by two externally governed market variables CO2 cred-

commercial safeguard for deployment.

its and bio-oil sales. The assessment shows a net margin

Fig.2 - (a) Raw material cost and (b) revenue distribution expressed as euro per tonne of biochar produced for the biochar production integrated into HIsarna process.

La Metallurgia Italiana - July-August 2026

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Attualità industriale - Industry news Sensitivity analysis: Biomass feedstock cost and CO₂

price rises to 150-250 €/t, the break-even boundary shifts

credit price based on figure 2 are the two principal uncer-

progressively, expanding the viable region across a wid-

tain market parameters governing production econom-

er range of both biomass prices and carbon credit levels.

ics, the former representing the dominant operating cost

This confirms bio-oil revenue is the strongest single eco-

and the latter the primary policy-driven revenue stream.

nomic lever in the integrated system, capable of compen-

Figure 3 shows that low bio-oil prices (50–100 €/t), the

sating for both high biomass costs and low carbon credit

system is broadly loss-making, with break-even confined

environments.

to low biomass costs and high carbon credits. As bio-oil

Fig.3 - Sensitivity analysis of the net price of biochar as a function of biomass price and CO2 credit values for different bio-oil prices.

CONCLUSIONS

process is thermally self-sufficient.

Based on the METSIM steady-state simulation the follow-

ing conclusions are drawn:

The integrated system is economically viable, but profitability is structurally governed by co-product markets rather than biochar value itself.

HIsarna off-gas heat recovery and recycled pyrogas

Bio-oil price is the primary driver of profitability. The

combustion together could fully sustain continuous

main risk is not energy volatility, but a simultaneous

slow pyrolysis at commercial scale, confirming the

decline in bio-oil and carbon credit values.

REFERENCES [1] [2]

Tanzer S.E., Blok K., Ramírez A., Iron and steel decarbonisation via BECCS in the HIsarna process. Int J Greenhouse Gas Control. 2020; 94:102903. Madhavan N., Dogan N., Yang Y., Meijer K., Flowsheet Modelling of Biochar Production Integration with HIsarna Ironmaking. [2026].

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Industry news - Attualità industriale

DOI 10.36146/2026_0708_57

Thermodynamics and Kinetic Modelling of Flash Reduction Ironmaking S. Sabah, A. Rizky Rhamdani, B. Mokhtarani, B. A. Nuraeni, G. Brooks, M.A. Rhamdhani, M. BootHandford, S. van Dorp

Flash reduction ironmaking is being developed as an alternative pathway for producing DRI from iron ore fines. Producing DRI directly from fines eliminates the pelletising step. Flash reduction in ironmaking was pioneered by Sohn et al., where they used co-current flow of hydrogen at a temperature between 1200 to 1600°C with iron ore particle size between 20 to 53 µm. Calix is developing Zero Emission Steel Technology (ZESTY), a flash hydrogen direct reduction ironmaking process where iron ore powder is fed from the top and 100% H 2 is introduced from the bottom. The working temperature is between 800 to 1100 °C with iron ore particle size < 500 µm. The process employs a vertically oriented reactor with indirect electrical heating, enabling hydrogen to serve solely as a reductant rather than as fuel. The technology has carried out pilot tests with different Australian iron ores and is planning to build a demonstration plant of 30,000-tonne-per-annum in Western Australia. The highest metallisation level of DRI produced from ZESTY pilot test was 98%. Increasing temperature from 900 to 1050°C and H 2/O_reduction ratio from 1.2 to 2 has a positive effect on the level of metallisation. Fayalite (Fe₂SiO₄) formation was observed in DRI produced from goethite/hematite ores. Thermodynamic calculations were undertaken to investigate the formation behaviour of fayalite under ZESTY operating conditions and to assess how ore chemistry and selected additives (e.g. CaO, MgO) influence its stability. These studies support a broader investigation into the role of fayalite in flash hydrogen reduction and its relevance to both metallisation and downstream ironmaking processes. Results showed that adding 10 wt% of CaO to the iron ore reduces the amount of H2 required to reach 100% metallisation level (up to 47%) as CaO can capture SiO2 and preserve FeO for hydrogen reduction. In a separate strategy, calculations predicted that adding 6.25 vol.% CH4 to H2 increased metallisation level from 82% to 86%. Kinetic study of ZESTY at 950 ºC showed that porosity of the ore and particle size played an important role in the reduction degree of all types of ores. Reduction by 100% H 2 was 3 times faster compared to 15% H 2. In a separate study of first order kinetic modelling of ZESTY showed that increasing temperature and hydrogen stoichiometric ratio enhanced the level of metallisation. Increasing particle size lowered the metallisation level through decreasing residence time. These findings are consistent with ZESTY pilot plant results.

KEYWORDS: THERMODYNAMICS; KINETIC MODELLING; FLASH REDUCTION; IRONMAKING; ZESTY. INTRODUCTION Currently, the ironmaking and steelmaking industries are going through the transition of decarbonisation to achieve its net zero goal by 2050. Hydrogen is widely regarded as one of the most promising clean energy sources because of its high calorific value, good thermal conductivity, and high reaction kinetics [1]. Though full application of H2 is not currently economically and technologically viable, utilisation of H2 shows the most promising results for decarbonisation [2]. There is also growing interest in developing technologies that directly use iron ore fines, such as fluidised bed technology [3],

La Metallurgia Italiana - July-August 2026

Shabnam Sabah, Ahmad Rizky Rhamdani, B. A. Nuraeni, Geoffrey Brooks, M.A. Rhamdhani

Heavy Industry Low-carbon Transition Cooperative Research Centre

(HILT CRC); FPD (Fluid and Process Dynamics) Group, Department of

Mechanical and Product Design Engineering, Swinburne University of Technology, Hawthorn 3122 VIC, Australia

Babak Mokhtarani

The University of Newcastle, Callaghan, NSW 2308, Australia.

Matt Boot-Handford, Sebastiaan van Dorp Calix Limited, Australia

pagina 57

Attualità industriale - Industry news flash reduction technologies such as flash ironmaking

by 60 to 96% compared to BF, depending on the usage of

technology (FIT) [4-7] developed by Sohn et al. and Zero

hydrogen [16]. On the other hand, ZESTY technology is

Emissions Steel Technology (ZESTY), currently being de-

based on Calix’s proprietary Flash Calcination (CFC) tech-

veloped by Calix in Australia [8-13]. These technologies

nology. The process (as shown in figure 1) uses an indirect

do not require pelletising or sintering steps and can make

heating approach of the CFC technology in which iron ore

iron in time scales of seconds to a few minutes. Following

fines (generally < 500µm) are gravity-fed from the top of

its commercialization in the 1950s, flash smelting tech-

the reactor, with hydrogen introduced from the base in a

nology has been widely utilized to produce copper and

counter-flow configuration. The iron ore fines are rapidly

nickel due to its high efficiency and productivity [14]. The

heated as they fall through the first few meters of the pro-

flash reduction concept was not introduced to ironmak-

cess and are subsequently reduced by the H2 to a direct

ing before the development of the FIT process. The FIT

reduced iron (DRI) product. Further downstream, this DRI

process utilises a co-current flow of hydrogen at a tem-

product can be smelted to remove gangue or can be made

perature between 1200 and 1600°C with iron ore particle

into briquettes [9, 10]. Since H2 is only used as a reduc-

size between 20 and 53 µm [6, 7, 15]. This process can use

tant, it is expected to minimise the use of hydrogen in the

natural gas, hydrogen, or a mixture of both. It has been

process. According to Mokhtarani et al. [8], the residence

reported that this process can decrease the consumption

time of ZESTY is between 45 seconds and about 2 min-

of energy by 30 to 60% and reduce the emission of CO 2

utes, varying with particle size and operating parameters.

Fig.1 - (a) Schematic of the ZESTY reactor (b) Process flow diagram of the ZESTY process [9]. The present paper describes the current status of the

tite ore (Fe3O4) from Western Australia [9]. The results

technology, the findings from ZESTY’s pilot testing, ther-

showed that the siderite and goethite/hematite achieved

modynamic modelling on the formation of fayalite, kinet-

metallisation levels of 91% (FC43-Siderite), 91% (HG57-

ics of the ZESTY process, and future development.

goethite/hematite), and 81% (FC43-Siderite) at 950°C, whereas MA68 (magnetite) reached metallisation levels of

PILOT PLANT RESULTS

54% at 1050 °C. The lower metallisation level in magnetite

In 2022, Calix carried out proof-of-concept campaigns

ore was likely due to its dense structure, whereas the rest

with four different iron ores, including a siderite (FeCO3)

of the ores had porous structures (as shown in figure 2).

sourced from Texas, USA, two hematite goethite (Fe2O3/ FeOOH) ores from Western Australia, and a magne-

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Industry news - Attualità industriale

Fig.2 - SEM images of porous structure of FC43, HG57, HG59, while denser MA68 iron ore [9]. In 2024, Calix conducted a pilot plant testing campaign

ores. Metallisation level increased from 49% to 92% and

(over 100 runs) with six Australian-sourced iron ores. The

61% to 98% for ores HG57 and SC43, respectively, when

pilot plant consists of a vertical reactor tube (ID = 0.2m, l

the temperature increased from 750°C to 950°C. There

= 18m) heated by 18 independently controlled electrical

is evidence indicating that higher temperatures increase

furnace zones. In the pilot study, trials were conducted in

metallisation; however, some variability is present in the

the range of 950 to 1050°C with iron ore at a feed rate be-

data, making the trend less distinct, particularly when

tween 60 and 200 kg/h in semi-continuous mode. H2 was

comparing results between 950 °C and 1050 °C. It is im-

injected at the base of the reactor at stoichiometric ratios

portant to note that some degree of sintering occurred

between 1.2 and 2 [13]. The details of the testing campaign

in the reactor at temperatures exceeding 1000 °C, poten-

are described in separate papers [12, 13].

tially hindering reduction kinetics and resulting in a lower

Increasing temperature increased the metallisation level

metallisation level for this scenario. Increasing the hydro-

of all ores. Figure 3 shows a comparison among all the

gen stoichiometric ratio also increased the metallisation

goethite hematite ores, including the proof-of-concept

level [12].

Fig.3 - Metallisation level of the DRI fines with changing temperature for goethite hematite ores [12]. La Metallurgia Italiana - July-August 2026

pagina 59

Attualità industriale - Industry news Particle size has a significant effect on the level of metalli-

metallisation increased. This result is consistent with the

sation. With increasing particle size, the level of metallisa-

findings from the previous proof-of-concept campaign

tion generally decreases (as shown in figure 4). When the

[10].

particle size decreased from 700 to 100 µm, the level of

Fig.4 - Metallisation level with varying ore particle size [12]. In the pilot campaign, the two magnetite ores (M07, M12)

achieved for magnetite ore was about 70% for the pre-ox-

and one pre-oxidised magnetite ore (OM07-pre-oxide

idised ore. Further work is underway to optimise ZESTY

M07) were tested. The maximum level of metallisation

for magnetite ores.

Fig.5 - Metallisation level of the DRI fines with changing temperature for magnetite ores [12]. Characterisation of the DRI fines derived from all goethite

amount of fayalite formation ranged from 5% to 20%. The

hematite ores showed formation of fayalite. Fayalite (Fe-

high fayalite results were associated with silica-rich ores,

SiO4) is the iron-rich member of the olivine group. Semi-

and further work is underway to limit its formation.

quantitative analysis of the XRD results indicated that the

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Industry news - Attualità industriale

The accumulation of water vapour in recycled reducing

8.2®. The details of the modelling work are described

gas is a common challenge in all hydrogen-based di-

elsewhere [17].

rect reduction processes. Increasing H₂O concentration

Figure 6 shows how the addition of CaO to a simulated

decreases the H₂/H₂O ratio and therefore lowers the re-

ore changes metallisation levels at different reduction

ducing potential of the gas. However, due to the short

temperatures compared to a simulated ore without any

residence times in flash reduction, the impact of water va-

CaO. The solid line indicates metallisation levels of a sim-

pour accumulation in the recycle loop on reaction kinet-

ulated ore by hydrogen with a composition of 90 wt.%

ics must be carefully assessed and managed. Currently,

FeO and 10 wt.% of SiO2 at different reduction tempera-

ZESTY operates with excess H 2 (stoichiometric ratio of 2)

tures, whereas the dashed line shows metallisation levels

to keep the H 2/H2O ratio high, but further work is required

of the same with 10 wt.% of CaO. Adding CaO improved

to understand the trade-off.

the reduction of FeO-10wt.% SiO2 mixtures, as it moves the lines to the left, which means a lower H2/FeO ratio is

THERMODYNAMIC MODELING

sufficient to achieve higher metallisation. This can be at-

Thermodynamic modelling was used to explore tech-

tributed to the presence of CaO, which captures SiO₂, and

niques to increase metallisation levels and suppress fay-

thereby preserves FeO for reduction by hydrogen [17].

alite formation. Calculations were carried out in FactSage

Fig.6 - Metallisation level of DRI vs H2/FeO ratio at different temperatures [17].

In a different investigation on fayalite suppression, a por-

level improves because the addition of CH4 reduces Fe in

tion of H 2 is substituted by CH 4, and CO separately. The

the other oxide phases, including fayalite. Adding CH4 also

effect of this gas addition on the metallisation level and

increased the carbon content of the product, as observed

carbon content of the DRI is studied and shown in figure

in figure 7. On the other hand, partially substituting H2

7. The metallisation of the DRI increased from 82% to 87%

with CO reduces the metallisation level, though the car-

when 6.25% of CH 4 was added to H2. The metallisation

bon content increased quite rapidly.

La Metallurgia Italiana - July-August 2026

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Attualità industriale - Industry news

Fig.7 - The effect of the addition of CH4 and CO separately to H2 in the reduction process [17].

KINETIC STUDY

and studied the mass loss from a 0.100g sample. The

Nuraeni et al. [10] carried out a kinetic study of the ZESTY

study showed that the reduction by 100% H2 was three

process in a TGA (Thermogravimetric Analysis) furnace

times faster compared to 15% H 2 (as shown in figure 8).

Fig.8 - Mass loss of Blend 3A/magnetite (125-300 µm) reduction by 100% H2, 950 ºC, 5 minutes [10].

La Metallurgia Italiana - Luglio-Agosto 2026

pagina 62

Industry news - Attualità industriale In another study by Mokhtarani et al. [8], a process model

tion was simplified as a single-step reaction from Fe₂O₃

for flash reduction was developed for hematite ores. The

to Fe, neglecting intermediate oxide phases. These sim-

modelling was carried out using Aspen Plus with two ki-

plifications were adopted to evaluate reactor-scale trends

netic models: the modified Sohn and the mixed control

in metallization and residence time rather than provide a

models with a set of assumptions. The reactor was di-

fully predictive description of the underlying multiphase

vided into 9 well-mixed zones, each 2 m long. Top and

and multistep reduction mechanisms. The Sohn kinetic

bottom zones were taken as pre-heating zones where no

model [18] is based on nucleation and growth kinetics. It

reactions occurred. The heat transfer in the seven reactor

incorporates the effect of temperature and partial pres-

zones was assumed to be infinitely fast, so that the gas-

sure of H2 and water vapor. The model has also been val-

es and particles were the same temperature as each other

idated with experimental results. The reduction of FeO

and as the wall. The particles were all at the mean diameter

by hydrogen during the final stage of hematite reduction

of the size distribution of the given sample. No fine par-

formed the basis for the development of the following

ticles were elutriated from the reactor. Hematite reduc-

empirical equation for hematite conversion [8]:

where, X= fractional reduction degree, R=gas constant,

idence time (s), and K = equilibrium constant. The con-

T=temperature, p=partial pressure (atmospheric), t=res-

stants were calculated for the reaction below:

On the other hand, a mixed-control model incorporates

ble 1 shows the comparison between simulated and ex-

both chemical reaction kinetics and diffusion resistance. A

perimental results. The findings from the model are con-

three-dimensional diffusion model (D3) together with the

sistent with the findings from the ZESTY pilot plant results

first-order reaction model (ROM1) is used for calculating

[8]. It is important to note that the experimental results for

the reduction of hematite. The details of the models are

FeO-110 and FeO-108 show variation from the general

described in a separate paper [8]. The modelling results

trend. The observed deviation may be attributed to dif-

indicated that increasing the temperature and the hydro-

ferences in metallization calculations based on ICP-AES

gen stoichiometric ratio improves the level of metallisa-

analytical results obtained from pilot-scale experiments.

tion. Also, increasing particle size reduced the level of metallisation through decreasing the residence time. Ta-

Tab.1 - Comparison between results from the modified mixed kinetic model and experimental work at 950 ºC and Hydrogen Stoichiometric Ratio of 2 [8].

Sample

dav(µm)

Residence time (s)

Metallisation level (%) Model

Experiment

FeO-109

FeO-114

81.9

FeO-110

220

68.6

FeO-108

280

67.6

La Metallurgia Italiana - July-August 2026

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Attualità industriale - Industry news CONCLUSIONS

briquetted iron (HBI), funded by an AUD 44.9 million grant

ZESTY’s pilot plant results showed that temperature and

from the Australian Renewable Energy Agency, with addi-

hydrogen stoichiometric ratio positively affect metalli-

tional investment of more than AUD 35 million from Rio

sation level, whereas increasing particle size decreases

Tinto under a joint development agreement [20]. The key

metallisation level. The kinetic modelling by Mokhtarani

challenges and successes of this technology depend on

et al. [8] showed similar findings to the pilot tests. Ther-

its ability to adapt to the current high cost of H₂, impro-

modynamic calculations showed that adding CH 4 to H 2 or

ved understanding of fayalite formation, optimisation for

adding 10% CaO to the high silica ore can suppress the

magnetite ores, innovative engineering solutions, and ad-

formation of fayalite. These estimations need to be veri-

dressing briquetting requirements to meet existing ship-

fied by further experimental work.

ping standards to enhance market flexibility.

As part of its development, ZESTY has completed the

ACKNOWLEDGEMENT

Front-End Engineering Design (FEED) study for the

The work has been supported by the Heavy Industry

30,000-tonne-per-annum demonstration project. The

Low-carbon Transition Cooperative Research Centre

main objective of the project was to examine and showca-

(HILT CRC), whose activities are funded by its industry,

se the feasibility of a standalone, full-scale processing

research, and government Partners along with the Au-

module [13, 19]. Calix is currently developing a demon-

stralian Government’s Cooperative Research Centre Pro-

stration facility capable of producing 30,000 tonnes per

gramme, with project number HILT RP1.015.

annum of hydrogen direct reduced iron (H₂-DRI) or hot

REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9]

[10] [11] [12]

[13]

[14]

Liu, Y., Z. Hu, and Y. Shen, CFD study of hydrogen injection in blast furnaces: tuyere co-injection of hydrogen and coal. Metallurgical and Materials Transactions B, 2021. 52(5): p. 2971–2991. Cavaliere, P., Hydrogen assisted direct reduction of iron oxides. 2022: Springer. Schenk, J.L., Recent status of fluidized bed technologies for producing iron input materials for steelmaking. Particuology, 2011. 9(1): p. 14–23. Sohn, H.Y., Energy consumption and CO2 emissions in ironmaking and development of a novel flash technology. Metals, 2019. 10(1): p. 54. Sohn, H.Y., Flash Ironmaking 2023, Boca Raton. Sohn, H.Y. From sulfide flash smelting to a novel flash ironmaking technology, in Celebrating the Megascale: Proceedings of the Extraction and Processing Division Symposium on Pyrometallurgy in Honor of David GC Robertson. 2016. Springer. Sohn, H.Y. and Y. Mohassab, Development of a Novel Flash Ironmaking Technology with Greatly Reduced Energy Consumption and CO2 Emissions. Journal of Sustainable Metallurgy, 2016. 2(3): p. 216–227. DOI: 10.1007/s40831-016-0054-8. Mokhtarani, B., et al., New Insights Into Hydrogen Reduction of Hematite in an Indirectly Heated Flash Reactor from Measurements and First-Order Modeling. Metallurgical and Materials Transactions B, 2025: p. 1–14. Boot-Handford M E, D.T., Nuraeni B A, Ignacio I R, Xia Y, Adipuri A, Gill M, Okely A, Hdgson P, Sceats M G, Brooks G, Calix’ Zero Emissions Steel Technology (ZESTY) – Flash Hydrogen Direct Reduction of Low-Grade Ores to Green Iron and Steel Products, in METEC & 6th ESTAD. 2023. Nuraeni B A, I.I.R., Brooks G, Nababan D. C., Rhamdhani M. A., Boot-Handford M.E., Xia Y, Dufty T, Sceats M G, Characterisation of Hydrogen DRI samples from ZESTY Process, in AISTech 2024 2024: Columbus, Ohio, USA. Sabah S, B.G., Rhamdhani M A, Development of Flash Reduction Technologies in H2DRI processes, in AISTech 2025: Nashville, Tennessee. Ormston C., X.Y., Dufty T., Sabah S., Al-Assafi S., Okely A., Fu J., Dorp S. Van, Rhamdhani A., Brooks G., Sceats, M.G., Boot-Handford, M.E., Breakthrough pilot testing results for the Hydrogen Direct Flash Reduced Iron (H-DRI) process, in AISTech. 2025: Nashville, Tennessee, USA. Sabah S, B.-H.M.E., Brooks G, Natha M G, Triana T, Rich B, Rhamdhani M A, Xia Y, Dufty T, Sceats M G, Nathan G, Chinnici A, Pilot plant study of the ZESTY flash hydrogen direct reduction ironmaking process. Journal of Sustainable Metallurgy, accepted in June 2026. McGregor, K. https://research.csiro.au/resourcesandsustainability/overcoming-inefficiencies-in-flash-smelting/. 2018 [cited 2023.

La Metallurgia Italiana - Luglio-Agosto 2026

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Industry news - Attualità industriale [15] [16] [17] [18] [19] [20]

Sohn, H.Y., M. Choi, and M. Olivas-Martinez. Novel flash ironmaking technology with greatly reduced energy consumption and CO 2 emissions, in 6th International Congress on the Science and Technology of Ironmaking. 2012. Sohn, H.Y., Fan, De-Qiu, Abdelghany, Amr, Design of novel flash ironmaking reactors for greatly reduced energy consumption and CO2 emissions. Metals, 2021. 11(2): p. 332. Rhamdani A. R., S.S., Brooks G, Rhamdhani M. A. , Fayalite formation in hydrogen reduction of iron ore and strategies to reduce it from a thermodynamic perspective. Under review at the Journal of Sustainable Metallurgy, 2026. Chen, F., et al., Hydrogen reduction kinetics of hematite concentrate particles relevant to a novel flash ironmaking process. Metallurgical and Materials Transactions B, 2015. 46: p. 1133–1145. Engineering, C., CALIX – ZERO EMISSIONS STEEL TECHNOLOGY (ZESTY)- FEED STUDY REPORT AND FINAL REPORT. 30/4/2024, Australian Renewable Energy Agency (ARENA). https://calix.global/news/calix-executes-joint-development-agreement-with-rio-tinto-to-provide-over-35m-of-value-for-zestygreen-iron-demonstration-plant/. Calix and Rio Tinto execute Joint Development Agreement Zesty Green Iron Demonstration Plant 2025 25.02.2026].

TORNA ALL'INDICE >

La Metallurgia Italiana - July-August 2026

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Atti e notizie - AIM news

Il futuro della metallurgia non solo in aula: EAC Summer School

Dalla prima Environmental Assisted Cracking Summer School di AIM emerge un modello che mette insieme università, industria e giovani ricercatori per affrontare le grandi sfide della transizione industriale. Quando si parla di formazione, si pensa spesso a un corso,

Il valore dell’iniziativa non si è misurato soltanto nella

a un programma didattico o a un calendario di lezioni. Ep-

qualità scientifica del programma, ma anche e soprattutto

pure, la formazione più efficace è quella che crea connes-

nella capacità di mettere in relazione mondi diversi come

sioni, mette in relazione competenze diverse e costruisce

università e industria; giovani ricercatori e professionisti

una comunità scientifica capace di affrontare insieme le

già inseriti nelle imprese; istituzioni scientifiche interna-

sfide del futuro.

zionali. È proprio in questi contesti che nasce l’innovazio-

È con questa visione che L’Associazione Italiana di Me-

ne.

tallurgia (AIM) ha promosso la prima Environmental As‑

La transizione energetica, la digitalizzazione dei proces-

sisted Cracking Summer School, organizzata a Milazzo

si, i nuovi materiali e l’Intelligenza Artificiale stanno cam-

in collaborazione con l’Università di Bergamo, l’Univer-

biando profondamente il settore metallurgico. In questo

sità di Messina e l’Università di Manchester, un’iniziativa

scenario, la competitività delle imprese dipenderà sem-

che ha riunito giovani ricercatori, professionisti e docenti

pre meno dalla sola disponibilità di tecnologie e sempre

internazionali attorno a uno dei temi più complessi della

più dalla capacità di sviluppare competenze avanzate.

scienza dei materiali: il degrado dei materiali in ambienti

Per questo motivo iniziative come la EAC Summer School

aggressivi.

rappresentano un investimento sul futuro dell’intera fi-

Le cinque giornate di lavoro hanno affrontato temi alta-

liera perché non formano semplicemente specialisti, ma

mente specialistici, dai meccanismi di stress corrosion

contribuiscono a costruire la prossima generazione di

cracking all’idrogeno, dalla corrosion fatigue alle applica-

ricercatori, tecnologi e manager che guideranno l’evolu-

zioni nei settori nucleare, oil & gas, infrastrutture, biome-

zione della manifattura.

dicale e aerospaziale. AIM COME PIATTAFORMA DI CONOSCENZA La prima edizione della Summer School ha coinvolto 36 partecipanti provenienti da diversi Paesi, confermando la crescente dimensione internazionale delle attività promosse da AIM. Il successo della prima edizione

della

Environmental

Assisted Cracking Summer School rappresenta un punto di partenza. Lo sguardo è già rivolto al 2027, quando la se-

La Metallurgia Italiana - Luglio-Agosto 2026

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Atti e notizie - AIM news conda edizione della Scuola di Tecniche elettrochimi‑

nazionale e contribuire alla crescita delle competenze

che accompagnerà il percorso verso la 17ª Conferenza

che accompagneranno l’evoluzione della metallurgia nei

Nazionale sulla Corrosione e Protezione, in programma

prossimi anni.

a Messina dal 14 al 16 giugno 2027. Per AIM significa confermare una direzione precisa: investire nella formazione avanzata, favorire il dialogo inter-

La Metallurgia Italiana - July-August 2026

Crediamo che il futuro della metallurgia si costruisca prima di tutto attraverso la conoscenza.

pagina 67

Atti e notizie - AIM news

Eventi AIM / AIM events

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