Leaching kinetics of gold bearing pyrite in H2SO4-Fe2(SO4)3 system
(1. Zijin Mining Group Co. Ltd., Shanghang 364200, China;
2. College of Zijin Mining, Fuzhou University, Fuzhou 350108, China;
3. State Key Laboratory of Comprehensive Utilization of Low-Grade Refractory Gold Ores, Shanghang 364200, China)
2. College of Zijin Mining, Fuzhou University, Fuzhou 350108, China;
3. State Key Laboratory of Comprehensive Utilization of Low-Grade Refractory Gold Ores, Shanghang 364200, China)
Abstract: Gold bearing pyrite leaching was conducted in H2SO4-Fe2(SO4)3 system at different reaction temperatures, with different ferric ionconcentrations, 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.
Key words: gold bearing pyrite; H2SO4-Fe2(SO4)3 system; leaching kinetics; activation energy; sulfur oxidation