REACTIONS OF AQUEOUS AU1+ SULFIDE SPECIES WITH PYRITE AS A FUNCTION OF PH AND TEMPERATURE

Abstract

The reactivity of aqueous Au (super 1+) sulfides with FeS 2 at pH = 3 and 6 for temperatures of 25 and 90 degrees 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 (super 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 4 (super -) solutions owing to the greater stability of Au(SH) (super 1-x) x complexes. This is the first evidence of Au (super 1+) on pyrite from bisulfide solutions using XPS.