Microstructure evolution during hydrogen-based direct reduction of iron oxides


Fossil-free ironmaking is indispensable for mitigating the massive CO2 emissions from the steel industry, accounting for ~7% of the total CO2 emissions and thus being the largest single cause of global warming. Hydrogen-based direct reduction (HyDR) of iron ores is one of the most promising techniques in that context. In this study, the hierarchical nature of HyDR will be revealed with a special focus on the spatial and temporal evolution of microstructure in this multistep solid-gas reaction. We employed several advanced characterization techniques to investigate the reduction kinetics, phase transformation crystallography, and three-dimensional porosity in this metallurgical process. The underlying reaction mechanisms are further discussed.


Dr.-Ing. Yan Ma received his doctoral (2020) and master’s (2015) degrees in metallurgical engineering from RWTH Aachen University, and bachelor’s degree (2013) from University of Science and Technology Beijing. He is the group leader of Sustainable Synthesis of Materials at Max-Planck-Institut für Eisenforschung (MPIE). His research interests pertain to fundamental physical and chemical mechanisms in hydrogen-based metallurgical processes, physical metallurgy of ferrous alloys, and high-entropy alloys. Dr. Ma is a holder of Walter Benjamin Position funded by the German Research Foundation (DFG) and he received the DGM Prize for Young Talent 2021 awarded by the German Materials Society (DGM).

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