Isothermal reduction kinetics and mineral phase of chromium bearing vanadium titanium sinter reduced with CO gas at 873 1273 K
Reduction of chromium bearing vanadium titanium sinter (CVTS) was studied under simulated conditions of a blast furnace, and thermodynamics and kinetics were theoretically analyzed. Reduction kinetics of CVTS at different temperatures was evaluated using a shrinking unreacted core model. The microstructure, mineral phase, and variation of the sinter during reduction were observed by X ray diffraction, scanning electron microscopy, and metallographic microscopy. Results indicate that porosity of CVTS increased with temperature. Meanwhile, the reduction degree of the sinter improved with the reduction rate. Reduction of the sinter was controlled by a chemical reaction at the initial stage and inner diffusion at the final stage. Activation energies measured 29.22 99.69 kJ/mol. Phase transformations in CVTS reduction are as follows: Fe2O3 Fe3O4 FeO Fe; Fe2TiO5 Fe2TiO4 FeTiO3; FeO*V2O3 V2O3; FeO*Cr2O3 Cr2O3.
International Journal of Minerals, Metallurgy, and Materials