Non-isothermal kinetic studies on the carbothermic reduction of Panzhihua ilmenite concentrate

Abstract

In this study, the kinetics of reduction of Panzhihua ilmenite concentrate by graphite under an argon atmosphere using the non-isothermal method was investigated by thermogravimetric analysis and mass spectrometry at heating rates of 10, 15, and 20 K·min⁻¹. Both the reactants and products were analysed by X ray powder diffraction (XRD) and scanning electron microscopy (SEM) to identify their phases and morphologies, respectively. The Málek method was used to analyse the reaction mechanism and model function. The results show that the reduction of ilmenite concentrate proceeded in three stages: mixed control, chemical reaction, and three-dimensional diffusion in that order. The Starink method was used to calculate the activation energy. The average apparent activation energies for the carbothermic reduction of raw ilmenite concentrate were 478, 617, and 468 kJ mol⁻¹ for the first, second, and third stage, respectively. The oxygen potential of tail gas during the reduction process was also obtained.