Thermodynamic and kinetic behaviours of copper slag carbothermal reduction process

Abstract

The thermodynamic and kinetic behaviors of carbothermal reduction of copper slag under different basicity were studied. The results show that the reduction process of Fe and Zn in copper slag is mainly endothermic reaction. The initial reaction temperature with C is lower than that with CO. The metallization rates of Fe and Zn at various temperatures gradually increase with the increase of basicity. With increasing basicity, the reduction rate of copper slag at each heating rate and the reduction degree at 1573 K gradually increase, and the initial reaction temperature gradually decreases. The increase of basicity from 0.06 to 1.20 makes the reaction activation energy decrease by 93.54 kJ mol⁻¹. The carbothermal reduction process of copper slag at each basicity conforms to the diffusion model, and the mechanism function is f(α) = (3/2)(1−α)^4/3[(1−α)^−1/3−1]⁻¹. The increase of basicity has a positive catalytic effect on the carbothermal reduction process of copper slag.