Hydrogen reduction behaviors and mechanisms of vanadium titanomagnetite ore under fluidized bed conditions

Abstract

Vanadium titanomagnetite ore has prominent latent applications in the recovery of iron, vanadium and titanium. In this study, the reduction effect and product characteristics of vanadium titanomagnetite ore using hydrogen as reductant under fluidized bed conditions were investigated by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometer. Under the optimal condition of gas flow rate of 1000 mL·min−1, reduction temperature of 850 °C, reduction time of 30 min and H2 concentration of 80%, the reduced product with a metallization degree of 90.22% was obtained. The titanium-bearing maghemite in raw ore was reduced to titanomagnetite, the massive generated rutile and minor hardly reducible Fe3-xMxO4(M = Mg/Al/Si/) hindered the further aggregation of metallic iron grains, and there was no FeO detected during the whole reduction process. Thus,the phase transformation process of vanadium titanomagnetite is suggested as follows: γ-(Fe,Ti)2O3 → Fe3-xTixO4 → FeTi5O8 → Fe2TiO5 → Fe2TiO4 → Fe + FeTiO3 → Fe + TiO2.