Enhance recovery mechanism of difficult to enrich copper oxide component in copper smelting slag: Sulfidization-xanthate flotation

Abstract

Copper smelting slag (CS), which is often overlooked, is a valuable solid-waste resource for reclaiming copper. Flotation is the most cost-effective method for its recovery. While most of the copper fraction can be easily recovered utilizing xanthate collection. However, the recovery effect of copper oxide components is poor, resulting in the waste of a large amount of copper resources. The sulfidization-xanthate method has exhibited some efficacy in recovering CS, due to its high economic value. However, the mechanism of using this method to recover CuO from CS is still unclear. This study utilized CuO samples to explore the recovery mechanism of the copper oxide fraction in CS within the sulfidization-xanthate system. Density-functional theory (DFT) theory and X-ray photoelectron spectroscopy (XPS) elucidated the sulfidization mechanism on the CuO surface, revealing the S formation of a Cu-S chemical bond on the CuO surface via chemisorption. Cu(I)-S and S_n²⁻, are the key species in activating CuO. Thermogravimetry analysis (TGA) identified that the CuO sulfidized surface adsorption less water than CuO surface. Zeta potential, ultraviolet visible (UV) and fourier transform infrared (FT-IR) tests illustrated the adsorption of sodium butyl xanthate (SBX) collection, exhibiting increased xanthate adsorption after Na₂S treatment. Molecular dynamics (MD) simulation indicated the relative concentration of water molecules on the surface of CuO sulfidized had decreased, while the SBX had increased. Flotation tests confirmed the recoverability of CuO using this method. The extended Derjaguin Landau Verwey Overbeek (EDLVO) theory illustrates that the adhesion between the CuO particles and bubbles is promoted. Overall, the sulfidization-xanthate method can enhance the recovery of CuO and provide theoretical guidance for practical production. It also lays the theoretical foundation for future studies.