Experimental and DFT studies on using Fenton reagent as oxidant to enhance the leaching of cuprite in sulfuric acid system

Abstract

The utilization of a Fenton reagent was implemented within this investigation to facilitate the oxidation of cuprite with the purpose of enhancing its leaching efficacy in sulfuric acid. The concentration of 0.007 mol/L Fenton reagent increased the extraction rate of cuprite from 69.43 to 91.53 %, which increased by 22.1 %. The XPS, AFM, SEM–EDS, and ToF-SIMS results showed that the leaching process of cuprite significantly enhanced its oxidation and the conversion of Cu(I) species to Cu(II) species by the Fenton reagent；Electrochemical tests revealed that as the concentration of the Fenton reagent increased, the strength of the oxidation reaction increased. After the adsorption of hydroxyl radicals (•OH) onto the cuprite surface, the population of Cu12-O12 decreased notably from 0.45 to 0.26, concomitantly with an expansion in bond length from 1.824 Å to 1.930 Å. As the population of Cu12-O7 decreased from 0.39 to 0.05, the bond length exhibited a notable increase from 1.849 Å to 2.241 Å. The findings indicated that following the adsorption of •OH on the cuprite (111) surface, structural instability ensued. The EPR test confirmed that the introduction of Fenton reagent into the reaction system generated •OH. Simultaneously, with the extension of reaction time, the concentration of •OH in the system decreased, resulting in a reduction of the signal peak intensity.