Infrared spectroscopic analysis of the sorption products of gold di-cyanide onto activated carbon

Conflicting results have been reported on the infrared spectroscopic (IRS) analysis of the sorption products of gold di-cyanide onto activated carbon. The present paper reports on our infrared spectroscopic findings. The infrared peak of CN in Au(CN)2− at 2140 cm−1 was detected in mixtures of activated carbon and solid KAu(CN)2 and also in activated carbon that was exposed to highly concentrated solutions of gold di-cyanide, but they were very weak in the second instance even though the gold concentrations on the carbon were of the same order as in the former case. It was not detected in activated carbon that was exposed to dilute solutions of gold di-cyanide. It is shown that the detected peaks could be due to KAu(CN)2 salt that crystallised from the concentrates solution during drying. It is concluded that once the gold is adsorbed the IRS technique may not be sensitive enough to detect the adsorbed species.