Dissolution of pure chalcopyrite with manganese nodules and waste water

Abstract

Chalcopyrite is the most abundant copper ore and, consequently, the most utilised to pro-duce metallic copper. The main route of treatment is through pyrometallurgical processes,but these emit significant quantities of SO2into the atmosphere (e.g. 182,000 t/year among allChilean smelters), producing mighty concern in the community. In this context, hydromet-allurgy is presented as an alternative that may be more environmentally friendly; however,the difficulties of processing sulphide minerals prevent achieving sustainable efficienciesfor the industry. In this research, a pure chalcopyrite mineral is leached at 25◦C with theaddition of manganese nodules as an oxidizing agent, and wastewater with a high con-centration of chloride that both enhances the dissolution and avoid the passivation of thechalcopyrite. The high concentrations of MnO2(4/1 and 5/1) allows that the potential valuescan be between 580 and 650 mV, which favors the dissolution of CuFeS2. The XRD showedthe formation of non-polluting species and, besides, they do not cause obstacles to the cop-per dissolution. High concentrations of chloride enable increasing copper solutions fromCuFeS2, attaining favorable outcomes when working with wastewater instead of seawater.