Sulfidization regulation of cuprite by pre-oxidation using sodium hypochlorite as an oxidant

Abstract

The direct sulfidization of cuprite is inefficient because cuprite is a copper-oxide mineral with a strong surface hydrophilicity. In this study, oxidant was used to modify cuprite surfaces to regulate the sulfidization of cuprite. Microflotation tests showed that the flotation recovery of pre-oxidized cuprite was nearly 25% higher than that of direct sulfidization flotation, which indicates that the cuprite surface activity was enhanced after pre-oxidation by Cu(I) species (weak affinity with sulfur ions) transformation to Cu(II) species (strong affinity with sulfur ions). Zeta potential, scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry results showed that pre-oxidation improved cuprite sulfidization and promoted the formation of copper-sulfide species on the cuprite surfaces. The mineral surface stability and thus, xanthate species adsorption on the cuprite surfaces were improved. The surface-adsorption measurements and infrared spectroscopy showed that a large amount of xanthate species was adsorbed onto the sulfidized cuprite surfaces after pre-oxidation, which enhanced the cuprite hydrophobicity and improved the cuprite flotation.