Leaching of low-grade chalcocite-covellite-chalcopyrite ore with sulphuric acid in absence and presence of oxidizing agents

Abstract

The leaching characteristics of low-grade chalcocite-covellite-chalcopyrite ore from the Cavnic Mine were investigated in sulphate media. The chemical composition of ore was: 0.37% Cu, 1.50% Zn, 2.00%, Pb, 0.38 g/t Au, 45.70 g/t Ag, 7.52% Fe, 7.92% S and 53.40% SiO2. During the experiments, the following parameters were modified: the leaching time, the leaching temperature and the quantity of ferric sulphate and of oxygen as oxidizing agents. From the shape of the teaching curves, three stages of the process were observed. The apparent activation energy depends on the period of leaching as well as on the presence of ferric ion and oxygen as oxidizing agents in the teaching medium. The study intends to establish the rate controlling reaction step, according to both the activation energies, and the analytical expressions for each period