Mechanism of Iron Powder to Enhance Solid-State Reduction of Chromite Ore

This study investigated the solid-state reduction characteristics of natural chromite ore and the effect of iron powder on the solid-state reduction characteristics of natural chromite ore under isothermal conditions below 1200 °C. The enhancement mechanism of iron powder on the solid-state reduction of natural chromite ore was revealed using optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS). The iron metallization rate of chromite ore exhibited a trend of increasing first and then decreasing with the addition of iron powder, and the optimal iron powder addition was determined to be 30%. The multi-step reaction gradually transforms into a single-step reaction with the increase in the dosage of iron powder. Iron powder facilitates the generation of a low-melting Fe-C alloy liquid phase and accelerates the speed of the solid-state reduction reaction of chromite ore and the disintegration of chromite spinel particles. When the iron powder dosage exceeds 30%, most of the multi-step reduction reaction of chromite ore is transformed into the single-step reduction reaction, which reduces the disintegration of chromite spinel particles and weakens the enhancement effect of iron powder on the solid-state reduction of chromite ore.