Leaching of chalcopyrite with hydrogen peroxide in 1-hexyl-3-methyl-imidazolium hydrogen sulfate ionic liquid aqueous solution

Seeking new solvents for green processing of chalcopyrite at low temperature with low energy and acid consumption as well as low pollutant release is key task in hydrometallurgy of chalcopyrite. In the present study, 1-hexyl-3-methyl-imidazolium hydrogen sulfate ([HMIm]HSO4) aqueous solution was used to leach copper from chalcopyrite at ambient temperature with hydrogen peroxide (H2O2) as oxidant. The effects of particle size, stirring speed, leaching temperatures, the types of ionic liquids, and the concentrations of H2O2 and [HMIm]HSO4 on copper extraction were systematically examined. A high copper extraction yield of 98.3% has been achieved in 10% (v/v) [HMIm]HSO4 aqueous at 45 °C after 120 min with 25% H2O2, particle size under 45 μm, and solid/liquid ratio of 10 g/L. It was found that particle size and temperature, as well as the concentrations of H2O2 and [HMIm]HSO4 had a significant influence on the leaching rate of chalcopyrite, while the stirring speed has little effect. The empirical kinetic model, − ln(1 − x) = kt was used to describe the kinetics of copper extraction in [HMIm]HSO4 aqueous solution, the results showed that the leaching process was controlled by a surface chemical reaction with an apparent activation energy of 52.06 kJ/mol.