Kinetics and mechanism of coal-based direct reduction of high-chromium vanadium-titanium magnetite

High-chromium vanadium-titanium magnetite (HCVTM) is a valuable resource containing metal elements such as iron, vanadium, titanium, and chromium. To recycle these elements, direct reduction is an efficient way. The mechanism and reaction kinetic parameters for the direct reduction of HCVTM were studied. Experimental results show that the reduction degree increases obviously when the C/O ratio and temperature increase. Thermodynamic analysis showed a dramatic mass loss in the direct reduction of HCVTM in the temperature range of 985-1160 degrees C. From 1200 to 1350 degrees C, the reduction curves for the isothermal reduction of HCVTM followed the same trend, with a sharp increase in the initial reaction zone and a slight increase in the reduction rate with increasing time, and finally, the isothermal reduction process of HCVTM was divided into several limiting stages with varying degrees, with inconsistent limiting factors for the reaction rate at different stages. The results also show that the activation energy decreases slightly at larger degrees of reduction. Also, the apparent rate constant k(T) increased with increasing reduction temperature, with lnk(T) showing a good linear relationship with temperature.

Automated summary

The direct reduction of high-chromium vanadium-titanium magnetite (HCVTM) was studied through experiments and thermodynamic analysis. The results show that the reduction degree increases with the increase of C/O ratio and temperature. Thermodynamic analysis reveals a significant mass loss in the direct reduction process of HCVTM within a specific temperature range. The isothermal reduction process can be divided into different limiting stages, with different factors affecting the reaction rate in each stage.