Advanced oxidation using sulfate radicals for the surface oxidation of Cu2O and the separation of copper via acid leaching
Qi Zuo, Dandan Wu, Shuming Wen, Jing Cao, Ziang Wang, Huiqin Chen
Abstract
The effect of Na 2 S 2 O 8 on Cu 2 O surface oxidation and leaching was investigated, and the presence of Na 2 S 2 O 8 transforms the surface of Cu 2 O into more easily leachable CuO, resulting in a 35.50% increase in the extraction rate of Cu than that without Na 2 S 2 O 8 . In the acid leaching system, O atoms combined with H + to form H 2 O, which was continuously separated from the surface to form vacancies. Cu(I) on the mineral surface formed Cu(0) and Cu(Ⅱ), of which Cu(Ⅱ) separated from the mineral surface and entered the solution, while Cu(0) was reconstructed on the surface, and a Cu-Cu metal bond with a bond length of 2.40 Å was appeared in the DFT calculation, which caused the content of Cu atom on the surface to be higher than that of O atom. After oxidation, high-spin Cu(Ⅱ) contributed by the 3 d orbital appeared on the mineral surface. The Cu(Ⅱ) content of the oxidized Cu 2 O surface was 19.80% higher than that of the pure Cu 2 O surface, indicating that the copper on the oxidized Cu 2 O surface was more easily extracted. Moreover, the adsorption energy of chemical adsorption occurring in the presence of oxidant (−1.91 eV) was more negative than that in the absence of oxidant (−0.21 eV).