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 degrees 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-Fe-2(SO4)(3) system.