Most of the world’s iron and steel is produced in blast furnaces. This process consumes a very large amount of energy and generates significant CO2 emissions due to the use of coal. New techniques will need to be developed and rolled out in order to achieve a gradual decarbonisation of iron- and steelmaking. One such alternative technology is direct reduction.
An environmentally friendly alternative to the blast furnace
The company Primetals Technologies Austria GmbH1 has been developing an innovative form of direct reduction for a number of years now. Its HYFOR® (hydrogen-based fine-ore reduction) production route uses a technology that is based on hydrogen. In this method, ultra-fine iron ore is directly reduced to DRI (direct reduced iron) in a fluidised-bed reactor, without any additional agglomeration steps such as pelletisation or sintering. This enables investment and operating costs to be reduced. The process uses green hydrogen instead of coal to reduce the iron ore, significantly lowering CO2 emissions. The aim is to use this new technology to cut primary energy consumption by 20 % and CO2 emissions by up to 100 %, shrinking the carbon footprint of crude steel production by 80 %.
Piloting a world-wide unique process
Nach Following some promising cold and hot testing at laboratory scale, Primetals Technologies Austria GmbH set up a HYFOR® pilot plant on the premises of its project partner voestalpine Stahl in Donawitz. Here the innovative, Austrian-made process has been studied further since 2021 in order to validate the laboratory results under real-life conditions. The pilot plant is made up of three parts: the preheating-oxidation unit, a gas purification system and the actual reduction unit. Inside the preheating-oxidation unit, the fine-ore concentrate is heated to over 800 °C and fed into the reduction unit, where 100 % hydrogen is used as the reduction gas. A dry dust extractor prevents any emissions from the processes involved. The hot direct-reduced iron (HDI) leaves the reduction unit at around 600 °C, before being cooled and conveyed out of the HYFOR® pilot plant.
Results and potential
The tests during the pilot phase have proved to be very promising. The HYFOR® technology is the first method worldwide that can process iron-ore concentrates where 100 % of the particles are less than 0.15 mm in size. This technique can be used on a wide range of ores including haematite and magnetite. During the two-year pilot phase, the plant will be trialling various types of iron ore in order to determine the ideal process parameters for making crude-iron production climate-friendly in the future. The volume of iron ore processed on these test runs is around 800 kg. The direct reduction plant has a modular structure, allowing it to be scaled up or down for each customer to suit steelworks of all sizes. The next step will be to expand pilot operation with the addition of a hot-briquetting test facility for making hot-briquetted iron (HBI). The aim is to validate the HYFOR® process and use the trial runs as a basis to gather the data required for implementing a prototype on an industrial scale.
https://energieforschung.at/projekt/fluidred-hot-bench-scale-plant/
„Primetals Technologies is committed to significantly reducing its carbon footprint and is determined to help the steel sector achieve its zero-carbon target. However, this calls for innovations and for steelmakers, scientists and the public sector to all work together. HYFOR® is an example of such a groundbreaking innovation that combines all of these factors. Such great results from developments like these would not be possible without the support of the Climate and Energy Fund.“
Etsuro Hirai
Chief Technology Officer and CEO Primetals Technologies Austria
1 Project partners: Primetals Technologies Austria GmbH (project management), voestalpine Stahl Donawitz GmbH, Metallurgical Competence Centre K1Met
