STUDIES ON THE USE OF MONOTHIOPHOSPHATES FOR PRECIOUS METALS FLOTATION

The fundamental mechanisms of dicresyl monothiophosphate (DCMTP) adsorption on gold, silver and gold-silver alloys have been investigated in the present work. The monothiophosphates are obtained by replacing one of the sulfur donors in the functional group of the corresponding dithio derivatives with oxygen. This substitution results in a true acid-circuit collector for bulk sulfide flotation that has also been found to increase gold recovery from primary gold ores. Voltammetric studies indicate that the adsorption of DCMTP is probably the result of a coupled chemical reaction involving an initial electron transfer step (E), followed immediately by a chemical reaction (C). Thus, the adsorption of DCMTP is controlled by both the E(h) and pK of the system. FTIR spectroscopic and contact angle measurements conducted under controlled potential conditions showed that DCMTP adsorption is potential-dependent. There are no indications of DCMTP adsorption on gold observed in these measurements.