Precious and base metals hydrometallurgy

Alternatives to cyanide

Page 8 of 9

Our researchers have been investigating less toxic alternatives to cyanide, the most promising of which is thiosulfate.

Research scientist sampling gold thiosulfate recovered using the patented ion exchange resin process.

Danielle Hewitt sampling for gold thiosulfate recovered using the patented ion exchange resin process. Photo by Darryl Peroni.

Thiosulfate is suited for niche processing applications such as sulfide and carbonaceous ores, where it can unlock gold more effectively than cyanide.

Our researchers offer expertise in the following areas:

  • developing tank, heap and in situ thiosulfate leach systems
  • analysing thiosulfate degradation products, both in leach solutions and adsorbed onto ion exchange resins
  • combining pressure oxidation (POX) and thiosulfate leaching to significantly increase gold recovery in refractory ores and concentrates
  • adapting thiosulfate processes for complex carbonaceous and copper/gold ores and concentrates
  • developing resin-in-pulp and resin-in-column processes for the recovery of gold thiosulfate complexes from leach solutions
  • demonstration of integrated thiosulfate leaching and recovery technology at laboratory and pilot scale.