KINETICS OF THE PRESSURE LEACHING OF SULFIDIZED CHALCOPYRITE IN H2SO4-O2 MEDIA

Abstract

An environmentally friendly route to copper extraction from chalcopyrite by a combination of pyrometallurgy and hydrometallurgy is the sulfidation process which consists of roasting chalcopyrite with sulfur at 350 - 400°C and subsequent leaching of the sulfidized material to dissolve the copper. In the framework of this non SO2 emitting alternative, the leaching kinetics of the sulfidized chalcopyrite concentrate in autoclave was studied. The pressure leaching was carried out with H2SO4-O2 solutions in the temperature range 125 - 150°C, and partial pressures of oxygen from 507 to 1216 kPa (5 to 12 atm). The results indicated that the copper dissolution rate increases with increasing temperature and partial pressure of oxygen from 507 to 1216 kPa. The leaching kinetics was analyzed by using a modified shrinking core model 1-(1- 0.45X)1/3 = kt, which represented well the experimental data. The determined activation energy was 93.5 kJ/mol and the rate dependency on the partial pressure of oxygen was of first order.