Hydrogen plasma smelting reduction

Our work focuses on advancing hydrogen plasma smelting reduction, which represents a promising, fossil-free steelmaking technology that integrates reduction, melting, and refining in a single step. Current research activities:

• Process model development (H2PlasmaRed)
• The use of optical emission spectroscopy (OES) for process monitoring (H2PlasmaRed, PlasmArc4Green).
• Plasma reduction of chromite with pre-reduction (TOCANEM 2).
• Process design for efficient reduction and dephosphorisation (grants, H2PlasmaRed, SusMet4Planet).
• Refractory wear (H2PlasmaRed).

These activities aim to improve the efficiency, scalability, and industrial readiness of HPSR.

Highlights

• A kinetic gas–metal–slag model was developed to predict changes in metal composition during hematite reduction, validated with laboratory experiments.
• An optimization-based design approach, combining computational thermodynamics and machine-learning surrogate models, was created to determine slag compositions that maximize reduction efficiency and phosphorus removal under industrial constraints.
• The effects of furnace parameters and slag composition on optical emission signals were investigated, enhancing real-time monitoring and control of HPSR using optical emission spectroscopy.

Selected publications

• E.-M. Sassi, E.-P. Heikkinen, T. Vuolio, R. Mattila, and V.-V. Visuri, “Experimental and Computational Investigation of Slag–Refractory Interactions under Conditions Relevant to Hydrogen Plasma Smelting Reduction,” Steel Research International, forthcoming
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• H.-P. Putaala, H. Pauna, A. Javed, U. Manzoor, D. Klapproth, V.-V. Visuri, A. Malfliet, R. Kallio, I. Souza Filho, M. Lindgren, D. Raabe, and T. Fabritius, “Hematite Leach Residue as a Material for Hydrogen Plasma Smelting Reduction: A Laboratory-Scale Study on Chemical Composition and Optical Emissions,” Metallurgical and Materials Transactions B, vol. 57, no. 3, pp. 4186–4202, 2026
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• A. Javed, I. Mäkelä, H. Pauna, H.-P. Putaala, U. Manzoor, D. Klapproth, A. Ganguly, B. Das, I. R. Souza Filho, D. Raabe, and V.-V. Visuri, “Thermodynamic-kinetic Modeling of Hematite Reduction in a Laboratory-scale Hydrogen Plasma Smelting Reduction Furnace,” Chemical Engineering Science, vol. 331, 2026. 124018
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• T. Vuolio, M. Zarl, I. Lappeteläinen, A. Javed, and V.-V. Visuri, “Optimization Based Experimental Design of Metal–Slag Experiments in Hydrogen Plasma Smelting Reduction Process,” Journal of Physics: Conference Series, vol. 1050, 2025. 012009.
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• A. Javed, I. Mäkelä, H. Pauna, H.-R. Putaala, U. Manzoor, D. Klapproth, I. R. Souza Filho, and V.-V. Visuri, “Kinetic Modeling of Hematite Reduction by Hydrogen Plasma Smelting Reduction in Laboratory-Scale,” Journal of Physics: Conference Series, vol. 1050, 2025. 012007.
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• H.-R. Putaala, H. Pauna, A. Javed, U. Manzoor, D. Klapproth, I. R. Souza Filho, V.-V. Visuri, A. Ganguly, M. Huttula, T. Fabritius, and D. Raabe, “Effect of Furnace Parameters on Optical Emission Spectra of Hematite Reduction by Hydrogen Plasma,” Metallurgical and Materials Transactions B, vol. 56, no. 4, p. 3381–3399, 2025
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