Abstract

Studying the dissolution of chalcocite allows to understand the behavior of the most abundant secondary sulfide ore in copper deposits, while digenite (Cu1.8S) and other intermediate sulfides (Cu2-xS) are often associated with chalcocite. The most common mechanism of dissolution is by two stages, and chloride ions benefit the kinetics of dissolution. In this study, a pure chalcocite mineral (99.9% according to XRD (X-Ray Diffraction) analysis) is leached in chloride media using NaCl and wastewater as the sources of chloride. Magnetic leaching tests are performed at 65, 75, and 95 degrees C, using a particle size between -150 and + 106 mu m. Chloride concentration and leaching time are the main variables. A substantial dissolution of chalcocite was obtained with 0.5 M H2SO4, 100 g/L of chloride and a leaching time of 3 h. The apparent activation energy (Ea) derived from the slopes of the Arrhenius plots was 36 kJ/mol. The XRD analysis proves the presence of elemental sulfur (S-0) as the main component in the leaching residue. No significant differences in copper extraction were detected when using 100 g/L of chloride ion or wastewater (39 g/L).