The recovery of gold from ammoniacal thiosulfate solutions containing copper using ion exchange resin columns

The loading of gold and copper, both individually and simultaneously, from thiosulfate solutions onto ion exchange resin columns and the subsequent elution of these species have been investigated. In the presence of copper, effective loading with good selectivity for gold can be achieved at pH 11, which balances the stability of the solution and minimizes the formation of poisoning polythionates. The loaded metals can be eluted with high efficiencies using a number of composite eluant solutions. These include sodium tetrathionate stabilized with sodium sulfite and ammonium thiosulfate (ATS), sodium sulfite coupled with ammonia, and sodium chloride with the addition of ATS. The addition of thiosulfate to the eluant seems to have a negative effect on the gold elution efficiency and should be avoided wherever it is possible. Of all the three eluants investigated, the sodium sulfite/ammonia combination is found to be the most efficient, but the sodium chloride/ATS combination is likely the most economical.