Leaching kinetics of gold bearing pyrite in H2SO4–Fe2(SO4)3 system

Gold bearing pyrite leaching was conducted in H2SO4–Fe2(SO4)3 system at different reaction temperatures, with different ferric ion concentrations, sulfuric acid concentrations and stirring speeds. The leaching kinetics and mechanism were studied. When the temperature ranged between 30–75 °C, the pyrite leaching was mainly controlled by chemical reaction with positive correlation to the ferric ion concentration. The activation energy obtained from Arrhenius empirical formula is 51.39 kJ/mol. The EDS and XPS analyses suggest that the oxidation of sulfur within pyrite is through a series of intermediate stages, and eventually is oxidized to sulphate accompanied with the formation of element sulfur. This indicates a thiosulfate oxidation pathway of the gold bearing pyrite oxidation in H2SO4–Fe2(SO4)3 system.