Sulfuric and hydrochloric acid adsorption on the reconstructed sulfur terminated (001) chalcopyrite surface

Abstract

AbstractDensity functional theory (DFT) calculations using localized numerical basis sets were used to investigate the interaction of HCl and H2SO4 with the reconstructed (001) chalcopyrite surface. The Cl−, SO, and HSO species are adsorbed on the iron sites. The proton is adsorbed preferentially on the disulfides present on the reconstructed surface leading to the SS bond breaking. Different configurations for all adsorption sites have been calculated and the geometric and energetic properties are discussed. The HCl and H2SO4 are leaching reactants normally used to extract copper from the chalcopyrite using the hydrometallurgical route. However, the leaching process became very slow after the first initial stages. It has been argued that the low kinetics is due to a passivation mechanism which involves polysulfides and jarosite formation on the surface. The interaction of the chemical species with the reconstructed chalcopyrite surfaces is investigated aiming to contribute to the knowledge of the chemical reactivity of the chalcopyrite surface at a molecular level. © 2012 Wiley Periodicals, Inc.