Kinetics of Oxidative Roasting of Complex Copper Concentrate

Abstract

As copper concentrates are progressively becoming more complex and low in grades, it is meaningful to remove sulfur from complex copper concentrates for smelting them by a carbon reduction process. In the present work, a kinetic study on the oxidative roasting of complex copper concentrate was experimentally investigated under nonisothermal condition in air using TGA equipment. Nonisothermal experiments were carried out at various linear heating rates up to 1123 K. Intermediates formed in each stage of the oxidative roasting of the complex copper concentrate were identified. After the first weight loss step, sulfate compounds were mainly formed in the second stage, and about 55% of sulfur contained in the concentrate was removed. In the third stage, the sulfur removal reaction was carried out, the rest of sulfur was nearly removed in this stage. Kinetics of the third stage were analyzed from the dynamic TGA data by means of Coats and Redfern equation. The nucleation and growth model yielded a satisfactory fit to these experimental data.