Sustainable steel from Australia and Germany

A research project on the direct reduction of fine ores in rotary kilns using hydrogen promises to significantly reduce CO2 emissions in steel production.

Approximately 7% of global anthropogenic CO2 emissions are caused by iron smelting, which uses fossil carbon as an energy source and reducing agent. It is possible to replace the reducing agent carbon with hydrogen. This process is currently being investigated on an industrial scale by Salzgitter AG and others as part of the SalcosS project. The direct reduction technologies established to date (e.g. Energiron-ZR, Midrex) are dependent on lumpy iron carriers. The processing and pelletizing of iron carriers is associated with considerable effort and high emissions in the producing countries. In addition, the lumpiness of the pellets restricts material transport, which slows and limits the reduction of the iron oxide pellets.

Direct reduction with hydrogen

As an alternative to established direct reduction technologies, fine ores can be reduced with hydrogen directly in the rotary kiln and then compacted for further processing. Emissions can be further reduced by eliminating the costly pelletizing and drying process. In addition, the increased contact surface between the solid iron oxide and the gaseous hydrogen significantly increases the efficiency of the process.

Development of process steps

Australian mining company Fortescue owns numerous iron ore deposits of varying composition. The processing of these ores into high-grade, clumpy primary products results in large quantities of low-grade fine ores that cannot currently be used.
The project will develop and optimize direct reduction with hydrogen in a rotary kiln to produce green iron for both high-grade and low-grade fine ores. Based on laboratory tests, the concentration of different ore grades with iron contents between 55% and 70% will be demonstrated in the existing pilot plant.
The aim of the project is to develop concepts for large-scale plants and logistics that will enable the project idea to be implemented on an industrial scale. Another focus is the establishment of an efficient energy and raw material trade between Australia and Germany.
The AMR of RWTH Aachen University focuses on the analysis of samples and the development of process steps for the processing of iron ore. The project will explore a sustainable, energy-efficient and largely dry method of processing iron ore to enable subsequent green hydrogen reduction for the production of high-quality pig iron.
The project is funded by the Federal Ministry of Economics and Climate Action (BMWK).
Source: RWTH Aachen University