Study On Oxidative Leaching Of Chalcopyrite In Ionic Liquid Media

The leaching of chalcopyrite is the core of hydrometallurgy of copper sulfide ore.The oxidation of chalcopyrite in traditional acidic medium has achieved remarkable progress,but acid consumption and low recovery rate of copper are key problems in this process.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.As a new designable green solvent with good selectivity and easy recycling,ionic liquid can greatly shorten the chalcopyrite leaching time and obviously improve the leaching yields of Cu.In this dissertation,ionic liquids were used to leach chalcopyrite.Some effective oxidants were studied for leaching chalcopyrite in ionic liquid aqueous solution.Various factors in leaching process were investigated and the leaching mechanisms in these mediums were analyzed,the best leaching rates and optimum conditions of leaching were obtained.It was found that H2O2,K2Cr2O7,KIO4 and KBrO3 oxidants were effective oxidants for chalcopyrite leaching in ionic liquid leaching medium.It was found that the optimum ionic liquid for leaching chalcopyrite highly depended on the choice of oxidant.A high copper extraction yield of 98.3%was obtained in ionic liquid[HMIm]HSO4 aqueous solution with H2O2 as oxidant,and the leaching process was controlled by surface chemical reaction with the activation energy of 52.06 kJ/mol.When K2Cr2O7 was used as oxidant,the leaching yield of chalcopyrite was 90.2%in ionic liquid[EMIm]HSO4 aqueous solution,and the rate-determining step was diffusion with an apparent activation of 36.26 kJ/mol.Ionic liquid[EMIm]HSO4 aqueous solution was used to leach copper with KIO4 as oxidant,the leaching process was mixed controlled and the leaching rate of chalcopyrite reached 85.9%.The copper extraction yield in ionic liquid[BMIm]HSO4 aqueous solution was 86.1%,and the leaching process was mixed controlled when KBrO3 was added to the leaching solution.