Effect of Cr2O3 addition on the oxidation induration mechanism of Hongge vanadium titanomagnetite pellets

As part of a research project to develop a novel clean smelting process for the comprehensive utilization of Hongge vanadium titanomagnetite (HVTM), in this study, the effect of Cr 2 O 3 addition on the oxidation induration mechanism of HVTM pellets (HVTMPs) was investigated in detail. The results showed that the compressive strength of the HVTMPs was greatly weakened by the Cr 2 O 3 addition, mainly because of a substantial increase in the porosity of the HVTMPs. The Cr 2 O 3 addition marginally affected the phase composition but greatly affected the microstructural changes of the HVTMPs. Increased amounts of Cr 2 O 3 resulted in a decrease in the uniform distribution of the hematite grains and in an increase in the Fe–Cr solid solutions (Fe 1.2 Cr 0.8 O 3 and Fe 0.7 Cr 1.3 O 3 ) embedded in the hematite grains. Moreover, the compact hematite was destroyed by forming a dispersed structure and the hematite recrystallization was hindered during the oxidation induration, which adversely affected the compressive strength. On the basis of these results, a schematic was formulated to describe the oxidation induration mechanism with different amounts of added Cr 2 O 3 . This study provides theoretical and technical foundations for the effective production of HVTMPs and a reference for chromium-bearing minerals.