Hydrogen-Based Direct Reduction of Industrial Hematite Pellets: Chemical Composition and Microstructural Evolution

ABSTRACT In recent years, the hydrogen-based direct reduction process has emerged as a sustainable solution to mitigate CO2 emissions. This paper presents the results of research focusing on the reduction behavior of industrial hematite pellets. The investigation involved using a custom-built thermogravimetric setup, which allowed for precise weight loss measurements during the reduction. The isothermal reduction experiments were conducted at 800°C under pure hydrogen. The surface morphology, microstructure, and chemical composition were investigated for an initial stage (33% reduced), an intermediate state (50% reduced), and near-complete reduction (>95% reduced). The results revealed a significant difference in the morphology of reduction products and metallization along the pellet radius.