Effect of Preoxidation Temperature on the Reduction Kinetics of Ilmenite Concentrate

The preoxidation of ilmenite affects its reduction kinetics because of the change in the phases and morphologies, depending on the oxidation temperatures. To confirm the effect of the oxidation temperature on the reduction kinetics, we examined the reduction reaction of ilmenite samples oxidized at 873-1273 K in a H-2-50 vol.% CO atmosphere at a reduction temperature of 1273 K. The reduction rate of the ilmenite oxidized at low temperature (873-1073 K) was faster than that of the ilmenite oxidized at high temperature (1173-1273 K). This behavior was ascribed to pseudobrookite, formed by combination of the hematite and rutile at a high oxidation temperature. Ilmenite samples, respectively oxidized at 873 K and 1273 K, were selected to study the effects of the hydrogen partial pressure and reduction temperature on reduction kinetics. The reduction of the ilmenite sample oxidized at 873 K was controlled by nucleation and nuclei growth. However, the sample oxidized at 1273 K was controlled by the chemical reaction occurring during the reduction. As regards the subsequent smelting process, the ilmenite oxidized during the preoxidation process had the advantages of a high conversion degree and low energy consumption.

Automated summary

The preoxidation of ilmenite affects its reduction kinetics, with high oxidation temperatures leading to slower reduction rates due to the formation of pseudobrookite. The effect of oxidation temperature on reduction kinetics is mainly manifested in nucleation/nuclei growth and chemical reactions. Ilmenite oxidized during preoxidation process has advantages of high conversion degree and low energy consumption in subsequent smelting process.