Microstructural evolution of iron powder during combustion and hydrogen-based direct reduction


A drastic decrease of our CO2 emissions is required in the next few years, and can only be achieved through a transition from fossil-fuel to sustainable carbon-free energy production. However, the latter is space and time dependent, hence safe, sustainable and high-density energy storage technology is needed. The combustion of iron powders seems very promising in this regard. Yet, little is known about their in-process morphological and microstructural evolution, which are critical features for the circularity of the concept, especially for the subsequent reduction of the combusted oxide powders back to iron. In this presentation, the different phase transformations, morphological and microstructural evolution of iron during its combustion are presented. Different combustion pathways were applied: laser-ignited single particle combustion on a microscopic level, and pilot scale industrial burner on a macroscopic level, resulting in different microstructures of combusted iron particles. The influence of these microstructural characteristics on the hydrogen-based reduction behavior of the combusted particles is also briefly presented. Finally, the main current difficulties faced for the iron metal fuel concept (nanoparticles, micro explosions) and their origin will be discussed.


Dr.-Ing. Laurine Choisez is currently working in Max Planck Institute for Iron research as a post-doc on the subject of sustainable iron powder fuel. She received her PhD in 2021 in Université Catholique de Louvain, Belgium, on the fracture mechanisms of a new family of beta metastable Ti alloys, and her master’s degree in Engineering in Chemistry and Materials Science in 2016 in the same university.  She also studied martensitic transformation in shape memory alloy in 2015 in MIT. Her current research interests are metal fuel, iron combustion, hydrogen-based reduction of iron ores, beta metastable Ti alloys and defect tolerant materials for 3D printing. Dr. Choisez received the Chair Lhoist Berghmans grant in 2015, the FNRS grant for doctoral researcher in 2016 and is currently a holder of the FNRS grant for chargé de recherche, received in 2022.

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