Reactions of aqueous Au (super 1+) sulfide species with pyrite as a function of pH and temperature

Abstract

The reactivity of aqueous Au 1 sulfides with FeS 2 at pH 3 and 6 for temperatures of 25 and 90 C has been investigated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDXA), and static secondary ion mass spectrometry (SSIMS). The presence of both Au 1 and metallic Au are observed upon the FeS 2 surface. We show that Au deposition is increased at elevated pH or temperature; but the amount of Au deposited is far lower than in AuCl solutions 4 owing to the greater stability of Au(SH) complexes. This is the first evidence of Au 1 1x x on pyrite from bisulfide solutions using XPS.