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

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 degrees 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