Copper leaching from complex chalcopyrite-rich ores: Utilizing mechanical activation and wastewater-based sulfuric acid system

Abstract

Complex chalcopyrite-rich ore is crucial in global copper resources, but is highly refractory in conventional sulfate leaching system. In this paper, we explore the leaching of complex chalcopyrite-rich ores employing a mechanically activated pretreatment combined with wastewater with high concentrations of chloride. The investigation delves into various parameters, including reaction temperature (60 to 90 °C), sulfuric acid concentration (0.005 to 2.0 M), chloride concentration (0 to 1.5 M), liquid/solid ratio (0 to 200), stirring speed (100 to 580 rpm), leaching time (0 to 4 h) and grinding time (0 to 7 h), to evaluate their impact on copper recovery from complex chalcopyrite-rich ores. Furthermore, a comprehensive kinetic analysis of copper leaching behavior was studied, encompassing specific surface area, amorphization degree, grain size, and microstrain. In the sulfuric acid system utilizing wastewater, the presence of mechanical activation and chloride content enhances copper leaching while mitigating the passivating effect of elemental sulfur. Notably, following a leaching period of 4 h at 80 °C, the copper leaching efficiency remarkably reached 89.46 %. In addition, kinetic analysis of copper leaching at temperatures ranging from 60 to 90 °C via a shrinking core model with R2 > 97 %, indicates that the leaching process of copper is primarily governed by solid product layer diffusion, with an activation energy of 54.32 kJ/mol. These findings highlight the efficacy of the proposed approach in optimizing copper recovery from complex chalcopyrite-rich ores, offering insights into the underlying mechanisms driving the leaching process.