Mojtaba Esmailzadeh

This study assessed the dissolution of chalcopyrite concentrate (CC) for copper extraction utilizing a threecomponent deep eutectic solvent (DES). The DES in this study was composed of choline chloride (ChCl), malonic acid (MOA), and p-toluenesulfonic acid (PTSA) in a 1:1:1 M ratio. To design and evaluate experiments, response surface methodology (RSM) was used. The key factors influencing the CC leaching process were time, temperature, milling time, and CC/DES mass ratio. Based on analysis of variance (ANOVA), a quadratic equation was derived to forecast copper and iron efficiencies, identifying temperature as the most significant factor in the dissolution process of CC. Based on the optimization findings for CC leaching in DES, the optimum conditions for leaching time, milling time, temperature, and CC/DES mass ratio were determined to be 80 min, 6 h, 100 ◦C, and 0.03 g/g, respectively. Under these conditions, the maximum extraction efficiencies for copper and iron were 83.9 % and 87.2 %, respectively. According to the molecular dynamic (MD) simulations, radial distribution function (RDF) analysis revealed that Cu and Fe form strong primary coordinations with Cl– ions, while MOA and PTSA contribute secondary stabilization via weaker interactions. A combination of complementary analytical techniques, including electrochemical analysis, spectroscopic data, and MD, consistently demonstrated that chalcopyrite leaching in the ChCl:PTSA:MOA DES proceeds via a chemically controlled, non-electrochemical pathway. Furthermore, kinetic modeling using the shrinking core model (SCM) revealed two distinct stages, both governed by surface chemical reaction control, with activation energies of 43.5 kJ/mol and 50.5 kJ/mol, respectively.