Overview
For decarbonised steel production, the hydrogen direct reduction (HDR) pathway is most technologically mature, whether coupled with an electric arc furnace (EAF) or potentially with a melter and basic oxygen furnace (BOF).
Concerns about these pathways, when applied to Pilbara ores in particular, include the high cost of hydrogen relative to conventional fuels, the likelihood of increased hydrogen use associated with carrying through the gangue and needing additional flux to remove it, and the need for increased temperatures in the final wüstite to iron reduction step, to effect reduction of low-purity ores.
Hydrogen plasma reduction (HPR) offers the potential overcome these barriers through the use of highly active hydrogen plasma that penetrates into the impermeable wüstite layer—offering the potential for a more efficient and effective use of hydrogen, at the cost of added electricity. HPR causes melting of the product, which may eliminate the need for a separate downstream melter and its associated energy demand.
Project Details
The overall goal of this project is to establish whether hybridised HDR-HPR offers a technologically and economically feasible pathway to large-scale green steel production. More specifically to:
- Conduct limited initial bench-scale tests to establish experimental proof of concept for combined HDR-HPR iron production, via in-sequence HDR and HPR tests with selected ore samples,
- Assess the technoeconomics of this concept and clarify that the use of HPR finishing can contribute to an overall lower steel cost, and
- Investigate the scale-up challenges for this technology and conceptualise a workable large-scale design.
Research Areas
Low-carbon iron exports from direct shipping ores
Outcomes
The project demonstrated a new method to produce green iron from low-grade ores.
The experimental work included small-scale tests using Pilbara iron fines. Initial reduction was performed in a hydrogen atmosphere using a tube furnace, followed by final reduction and melting with a hydrogen plasma torch.
The project also developed and tested an in-flight hydrogen plasma smelting reactor (HPSR), which successfully reduced iron oxides and partially reduced HDR powders to create metallic iron with 100% Fe content. Some metallic droplets were found enclosed in slag, while other samples formed large iron clusters free of phosphorus.
Early tests with a low-energy plasma reactor explored ways to reduce the energy required for plasma processing.
A technoeconomic analysis of hydrogen plasma steelmaking identified a novel two-stage plasma-basic oxygen furnace (BOF) process as cost-competitive for some scenarios. However, HDR combined with an electric arc furnace (HDR-EAF) remains slightly cheaper for high-grade ores, at 667 USD/tLS (USD per tonne of liquid steel) compared to 677 USD/tLS for plasma steelmaking.
Achieving cost parity with HDR-EAF for medium-grade ore requires a minimum plasma-smelter efficiency of 82%. Pre-reducing ore to wüstite (an iron oxide mineral) before plasma smelting can lower costs when efficiency is below this threshold.
Scaling up the HPSR technology presents both challenges and opportunities. Improvements to the in-flight plasma reactor being explored at Swinburne University will support future research. Ultimately, the plasma-BOF process is emerging as a viable option for processing low-grade Pilbara ores.
Published Scientific Papers
- Cooper C, Brooks G, Rhamdhani MA, Pye J & Rahbari A. Technoeconomic analysis of low-emission steelmaking using hydrogen thermal plasma. Journal of Cleaner Production, 2025, 144896, ISSN 0959-6526, doi: 2025.144896.
- Satritama B, Cooper C, Fellicia D Pownceby MI, Palanisamy S, Ang A, Mukhlis RZ, Pye J, Rahbari A, Brooks GA, Rhamdhani MA. Hydrogen Plasma for Low-Carbon Extractive Metallurgy: Oxides Reduction, Metals Refining, and Wastes Processing. J. Sustain. Metall. 2024.
Project Summary
HILT CRC Project Summary RP1.010 Hybrid hydrogen direct and plasma reduction of iron ore