Kinetic study of Cu2S–FeS mixtures in an oxidative environment by thermogravimetric and thermodynamic analysis

Abstract

Two samples of Cu2S–FeS mixtures were prepared in order to study the thermal oxidation evolution of the raw materials used during the first and second sub-stages of slag blowing in a converter furnace. To determine the thermal evolution in an oxidative environment, thermogravimetric analysis (TGA) was performed on both samples at four linear heating ramps (5, 10, 15 and 20 °C min−1), obtaining similar curves in both cases. Of the methods studied, Friedman, Coats-Redfern, Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose, the latter was found to be the most suitable to represent the oxidative evolution of Cu2S–FeS mixtures. The kinetic parameters calculated using Kissinger-Akahira-Sunose method are highly dependent on the degree of conversion. The results obtained for the activation energy ranging between 10 and 20 Kj mol−1 for conversion rates of 0.2, and between 30 and 50 Kj mol−1 for conversion rates of 0.9. In addition, a thermodynamic computational model was developed to determine the reactions taking place during the oxidation of the Cu2S–FeS mixtures.