UNDERPOTENTIAL DEPOSITION OF DITHIOPHOSPHATE ON CHALCOCITE

An electrochemical and electron spectroscopy investigation of the interaction of diethyl dithiophosphate with chalcocite (Cu2S) at pH 9 has been undertaken in order to explore differences between submonolayers of thiol collectors adsorbed on sulfide minerals and the corresponding metal thiol compounds. The chemisorption of the initial monolayer of dithiophosphate on chalcocite gives rise to a prewave on voltammograms at underpotentials to copper dithiophosphate formation. The equilibrium coverage of chemisorbed dithiophosphate was determined as a function of potential and found to obey a Frumkin isotherm. X-ray excited Cu(LMM) Auger electron spectra revealed that the copper atom environment in the submonolayer is similar to that in chalcocite, and significantly different from that in the readily formed subsequent layers of copper dithiophosphate.