Adsorption of gold from gold copper ammonium thiosulfate complex onto activated carbon and ion exchange resins

There area number of lixiviants used for the extraction of gold from ores. Cyanide is commonly used due to its low cost and its high extraction efficiency for gold from a wide range of gold containing ores. However due to environmental considerations, other lixiviants are used for the extraction of gold. One of the lixiviants used is copper ammonium thiosulfate. This reagent is capable of extracting gold from refractory and carbonaceous gold ores. Previous studies indicate that the chemistry of gold copper ammonium thiosulfate is not fully understood and gold adsorption onto activated carbon has not been very successful. Hence, studies of the adsorption of gold from gold copper ammonium thiosulfate had been performed on different ion exchange resins, Amberlite IRA-400, Dowex and EIchrom. It was found that Amberlite IRA-400 was very effective in the adsorption of gold. The studies were conducted by varying the parameters like pH and temperature for the effective adsorption of gold onto the ion exchange resin. The elution of gold from the ion exchange resin was successful using 5 M NaCl solution wherein 76% of gold adsorbed was eluted.