Hy4Smelt: Construction Begins on Austria’s Largest Climate Protection Research Project at the voestalpine Site in Linz
25. September 2025 | International plant engineering company Primetals Technologies, globally active steel and technology group voestalpine, and Rio Tinto, one of the world’s largest mining groups, are taking a completely new and promising approach to developing steel production with net-zero CO₂ emissions. With the official groundbreaking ceremony for Hy4Smelt, construction began today at the voestalpine site in Linz for the world’s first industrial-scale demonstration plant capable of combining two innovative processes: hydrogen-based direct reduction for ultra-fine iron ores and an electric smelting process. Commissioning of the industrial-scale demonstration plant is planned by the end of calendar year 2027, and the project is scheduled to conclude in 2030. Total costs amount to approximately EUR 170 million. Hy4Smelt is therefore the largest climate protection research project in Austria.
The Hy4Smelt demonstration plant combines hydrogen-based direct reduction (HYFOR®) for ultra-fine iron ores with an electric smelting process (smelter). The directly reduced iron (DRI), or sponge iron, produced in the HYFOR process is melted in the smelter, where slag is separated. This creates high-quality pig iron for the production of demanding steel grades, analogous to today’s blast furnace process. The slag is then used as a raw material for further industrial processing.
“We are pleased that construction work for the Hy4Smelt demonstration plant in Linz is now beginning. This significant milestone highlights the successful collaboration within the consortium. By providing our iron ore resources as well as our technical expertise, we are contributing to the research of innovative processes for low-emission iron production. Although there is still much to learn, we are confident that fluidized bed and electric smelting technologies offer promising potential for the sustainable advancement of the steel industry.”
voestalpine has long been regarded as an environmental benchmark within the industry and, with greentec steel, has established a clear step-by-step roadmap for transforming its steel production. Beginning in 2027, one green electricity-powered electric arc furnace will go into operation at each of its sites in Linz and Donawitz. By 2029, this is expected to reduce CO₂ emissions by up to 30% compared with 2019 levels. This corresponds to almost 5% of Austria’s annual CO₂ emissions, making greentec steel the largest climate protection program in Austria.
Innovative Solutions from Primetals Technologies for a New Era of Steel Production
“With today’s groundbreaking ceremony, we are taking a decisive step toward CO₂-neutral iron production. We are introducing technological solutions that have the potential to revolutionize the entire industry,” explained Dr. Alexander Fleischanderl, CTO and Head of Green Steel at Primetals Technologies. “The steel industry must pursue new paths. Coal-fired blast furnaces, which have formed the backbone of iron production for centuries, cause significant and growing environmental impacts. This is exactly where HYFOR and the Smelter come in — with these solutions, we are paving the way for a new era in ironmaking.”
For the industrial-scale Hy4Smelt demonstration plant in Linz, Primetals Technologies has also entered into a strategic partnership with Mitsubishi Corporation as a co-investor.
Raw Materials and Expertise from Rio Tinto
Rio Tinto will provide 70% of the iron ore required for the Hy4Smelt plant and will also contribute technical support to the project. In addition, the company is involved in the further development and future commercialization of the HYFOR and Smelter technologies.
“We are pleased that construction work for the Hy4Smelt demonstration plant in Linz is now beginning. This significant milestone highlights the successful collaboration within the consortium. By providing our iron ore resources as well as our technical expertise, we are contributing to the research of innovative processes for low-emission iron production. Although there is still much to learn, we are confident that fluidized bed and electric smelting technologies offer promising potential for the sustainable advancement of the steel industry,” said Rafael Azevedo.
Successful Advancement of Existing Research Projects
The HYFOR® (Hydrogen-based Fine-Ore Reduction) process, a forward-looking technology developed by Primetals Technologies, has been in operation as a pilot plant at the voestalpine site in Donawitz since 2021. Combined with the newly developed Smelter from Primetals Technologies, these two technologies are being applied industrially together for the first time in the Hy4Smelt project. The hydrogen required for direct reduction in the Hy4Smelt plant will come from H2FUTURE, the world’s longest-running PEM electrolysis plant, located in Linz. As part of the follow-up project H2FUTURE Follow-Up, research activities on hydrogen production are being consistently advanced together with VERBUND, focusing on purity, pressure increase, and storage.
With total costs of around EUR 170 million, Hy4Smelt is Austria’s largest climate protection research project in terms of investment volume. The European lighthouse project is co-financed by Austrian funding institutions (aws/Twin Transition and KPC/Transformation of Industry) and European funding programs (RFCS/Clean Steel Partnership and Clean Hydrogen Partnership/Hydrogen Valleys). Scientific partner is K1-MET, one of the leading international competence centers for metallurgical and environmental process development.
About voestalpine
voestalpine is a globally leading steel and technology group with combined materials and processing expertise. The internationally active group operates around 500 companies and locations in more than 50 countries across all five continents. Listed on the Vienna Stock Exchange since 1995, voestalpine is one of the leading partners to the automotive, mechanical engineering, aerospace, and energy industries, and is also the global market leader in railway infrastructure systems and special sections. The company is committed to global climate targets and is pursuing a clear transformation plan for steel production through greentec steel. In the 2024/25 business year, the group generated revenue of EUR 15.7 billion, EBITDA of EUR 1.3 billion, and employed around 49,700 people worldwide.
About Primetals Technologies
Primetals Technologies, headquartered in London, is a pioneer and world leader in engineering, plant construction, and lifecycle services for the metals industry. The company offers a complete portfolio including electrics and automation, digitalization, and environmental solutions across the full iron and steel production chain, as well as advanced rolling solutions for the nonferrous metals sector. It is a group company of Mitsubishi Heavy Industries and employs around 7,000 people worldwide.
About Rio Tinto
Rio Tinto is a leading global mining and materials company. It operates in 34 countries and produces iron ore, copper, aluminum, critical minerals, and other materials needed for the global energy transition.
About Mitsubishi Corporation
Mitsubishi Corporation is a global integrated business enterprise operating together with offices and subsidiaries worldwide. It has eight business groups covering sectors such as environmental energy, materials solutions, mineral resources, urban development and infrastructure, mobility, food industry, smart-life creation, and power solutions.