Construction Begins in Austria to Demonstrate Industrial-Scale Hydrogen Steelmaking Process
September 30, 2025
Primetals Technologies, a UK-based company wholly owned by Mitsubishi Heavy Industries, has partnered with Rio Tinto (UK–Austria industrial and metals group) and Austrian steel technology firm voestalpine to build an industrial-scale demonstration plant – Hy4Smelt – using hydrogen-based steelmaking technology at voestalpine’s site in Linz, Austria. A groundbreaking ceremony was held on September 25.
The Hy4Smelt plant will operate continuously by combining two technologies:
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HYFOR – a hydrogen-based fine ore reduction technology, and
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Smelter – a hydrogen-based direct reduction and electric ironmaking technology.
Although capable of processing all grades of iron ore, the plant will primarily target low- to medium-grade ores, which represent the majority of global supply. The facility is scheduled to come online by late 2027, with a planned processing capacity of 3 tonnes per hour.
HYFOR is the world’s first direct-reduction process for fine iron ore, producing direct reduced iron (DRI) and hot briquetted iron (HBI) without pelletizing or sintering. It uses low-pressure reducing gas, recycles dust captured during production, and achieves high metallization rates. Primetals has spent 10 years developing HYFOR and has conducted over 50 pilot trials since 2021.
The Smelter furnace, powered by renewable energy, melts and further reduces DRI to produce hot metal, pig iron, and high-value slag, which can be used as an alternative additive to cement clinker.
By using certified green hydrogen supplied by the existing H2Future electrolysis plant at voestalpine, the project has the potential to achieve net-zero CO₂ emissions, while producing blast furnace-equivalent hot metal. HYFOR and Smelter are expected to be commercialized from 2028.
Rio Tinto will supply about 70% of the iron ore required for Hy4Smelt and provide technical support for further development and commercialization. Mitsubishi Heavy Industries will participate as a strategic investor, contributing expertise in raw material supply, product trading, and market demand insights.
