Optimizing pellets for efficient green steel production
MPI-SusMat scientists win Outstanding Paper Award 2024
Research group leader Yan Ma and his co-authors, Isnaldi Souza Filho, Xue Zhang, Supriya Nandy, and colleagues from the Max Planck Institute for Sustainable Materials (MPI-SusMat) have been honoured with the Outstanding Paper Award 2024 by the International Journal of Minerals, Metallurgy and Materials. Their study sheds light on the heterogeneous reduction behaviour of iron ore pellets and how their local microstructure affects the efficiency of hydrogen-based direct reduction, a key process in carbon-free steelmaking.
Steel remains a cornerstone of modern infrastructure, yet its production is responsible for 8% of global CO₂ emissions and 35% of manufacturing-related emissions. The awarded research highlights the crucial role of iron ore pellets in improving the efficiency of hydrogen-based direct reduction for green steel production. The structure, porosity, and phase transformations of the ore pellets significantly influence reduction kinetics. “Hydrogen diffuses faster through iron ore pellets than carbon-based reductants, yet the final stage—from wüstite to metallic iron—is surprisingly slow, consuming more hydrogen than expected. This makes the process extremely costly,” explains Ma, the study’s first author.
Using synchrotron high-energy X-ray diffraction and electron microscopy, the researchers analysed the microstructural evolution of commercially available direct reduction pellets. Their findings reveal that current pellets are not optimized for hydrogen-based reduction. By refining their size, porosity, and microstructure, carbon-free steel production can become more efficient and cost-effective.
The study was conducted in collaboration with the German Aerospace Center and RWTH Aachen University, contributing valuable insights towards the development of sustainable steelmaking technologies.
