Chalcopyrite Leaching in Alkaline Monosodium Glutamate Solutions: Process Optimization and Kinetic Study

This study investigated the kinetics of chalcopyrite dissolution in an alkaline monosodium glutamate (MSG) solution using H2O2 and KMnO4. The aims were to optimize process conditions for maximum copper dissolution and to study the kinetic mechanism of dissolution under varying conditions, such as particle size, oxidant type and concentration, temperature, and the presence of gangue minerals. Results showed that KMnO4 exhibited better oxidative efficiency and stability than H2O2, yielding copper recoveries above 90% in most conditions while keeping the dissolution of some gangue metals, such as calcium, magnesium, and iron, lower, thereby reducing MSG consumption. Temperature and particle size were the most important factors in the effects on leaching kinetics; smaller particles allow higher initial reaction rates, while larger particles allow prolonged dissolution. The shrinking core model (SCM) was thus used to perform kinetic analysis and determine that diffusion controls the leaching process through the product layer. The calculated activation energies of 18.2 kJ/mol of MSG-H2O2 and 17.3 kJ/mol of MSG-KMnO4 confirm the diffusional mechanism.