Extraction of copper from chalcopyrite with potassium dichromate in 1-ethyl-3-methylimidazolium hydrogen sulfate ionic liquid aqueous solution. (1st October 2021)

• Record Type: Journal Article
• Authors: Hu, Junxian; Zi, Futing; Tian, Guocai
• Is Part Of: Minerals engineering. Volume 172(2021)
• Publication Date: 2021-10-01
• Subjects: Chalcopyrite -- Copper extraction -- 1-ethyl-3-methylimidazolium hydrogen sulfate -- K2Cr2O7 -- Kinetics -- Ionic liquids aqueous solution -- Oxidizing leaching; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2021.107179
• Languages: English
• ISSNs: 0892-6875

Abstract

Highlights: A new leaching system ([EMIm]HSO4 -K2 Cr2 O7 aqueous solution) was developed for chalcopyrite leaching. Optimum chemical conditions for chalcopyrite leaching were systematically examined. A high copper extraction yield of 90.2% was achieved within 90 min under the optimized conditions. The leaching process was controlled by the diffusion through a protect layer of elemental sulfur and pyrite. Abstract: Developing new and sustainable leaching system with limited release of pollutant and low acid and energy consumption is a challenge for copper extraction from chalcopyrite. In this work, a hydrometallurgical process for chalcopyrite dissolution in 1-ethyl-3-methyl-imidazolium hydrogen sulfate ([EMIm]HSO4 ) media with potassium dichromate (K2 Cr2 O7 ) was developed, and the leaching behavior of chalcopyrite with various parameters, such as kinds of ionic liquids (ILs), concentrations of [EMIm]HSO4 and K2 Cr2 O7, stirring speed, leaching temperature, and particle size were discussed in detail. The result show that the most effective ILs medium for chalcopyrite dissolution was varied with the specific oxidant. The leaching rate of chalcopyrite was significantly enhanced by increasing temperature, concentrations of K2 Cr2 O7 and [EMIm]HSO4, and decreasing particle size, while it has little to do with the increasing of stirring speed. The maximum copper extraction yield of 90.2% was reached within 90 min under the following optimized conditions: 10 g/L of solid/liquid ratio, 10 vol% of [EMIm]HSO4 concentration, 0.1 M of initial K2 Cr2 O7 concentration, stirring speed of 200 rpm, the temperature of 70 °C and particle size of −45 µm. The leaching process of chalcopyrite in [EMIm]HSO4 -K2 Cr2 O7 aqueous solution follows an empirical kinetic model 1-2/3 x - ( 1 - x ) 2/3 = k d t with the apparent activation energy of 36.26 kJ/mol, which was limited by the diffusion through a protect layer of elemental sulfur and pyrite.