Electrochemical and interfacial studies on the oxidation of pyrite at high altitude area

Abstract

Pyrite is the most abundant metallic sulphide ore in nature and has semiconducting properties that induce electrochemical reactions. Scholars have conducted many related electrochemical studies, but studies on the unconventional environment with low dissolved oxygen (DO) in high altitude area are relatively few. In this study, we have designed and built a high altitude simulation test platform, investigated the electrochemical property changes of pyrite, analyzed the form of DO interaction pattern by DFT calculations, and studied the interface properties of the pyrite by XPS and SEM-EDS. We found DO takes away the H atoms from the water molecules on the pyrite surface and promotes hydroxylation by DFT calculations. The DO content in the flotation slurry at high altitude areas is lower due to low air pressure. Under the weakly alkaline (pH = 8.5) condition, the surface corrosion rate is lower at high altitude condition, which is favorable to the formation of the S⁰ deactivation layer, which improves the hydrophobicity of the pyrite surface and makes it easier to adsorb fine particles. The study provides a theoretical basis for the pH-DO value adjustment technique for sulphide ore flotation and also provides guidance for the regulation of pyrite surface wettability at high altitude areas.