Effect of activated carbon on the thiosulfate leaching of gold

Abstract

The catalyzed thiosulfate leach of gold from oxide ores has been evaluated. The addition of fine activated carbon resulted in increased dissolution rates and gold recoveries. It was hypothesized that activated carbon and gold form galvanic couples, and that the rate of oxygen reduction increased due to the increased surface area available on activated carbon. The use of activated carbon as catalyst in the thiosulfate leach of gold is a process alternative that may not require the addition of surrogate oxidants (like copper), can work at temperatures as low as 30 °C, and thiosulfate degradations of 2.1 kg per ton of ore or lower, making it an attractive alternative for the leaching of gold.