QUEBEC – Gold extraction without the use of toxic cyanide and mercury is a step closer to reality, thanks to Dundee Sustainable Technologies Inc. (DSTI) of Montreal. The company began building a demonstration plant for its proprietary technique almost a year ago in Thetford Mines. Commissioning is scheduled before the end of 2014.
The plant, which uses DSTI proprietary cyanide-free gold extraction process, has a capacity of 15 t/d. The technology is officially recognized as "green" by the provincial and federal governments, who together have awarded Dundee $5.7 million toward construction of the plant.
The new process has been successfully demonstrated in the lab and a pilot plant. Dundee tested more than 100 tonnes of ore from 22 different countries during more than 1,000 hours of operation. Recovery of gold was above 90% in all cases and above 95% in most cases. The technology is described as a "closed circuit, bromine assisted chlorination process."
Dundee Technologies holds 25 patents in 19 countries for its metal extraction processes, arsenic neutralization methods, and fertilizer production. Fourteen more patent applications are pending worldwide.
Readers are urged to visit DundeeTechnologies.com to learn more about the company and its green processes.
I have yet to understand why the halogen family toxicity & handling characteristics are any less than sodium cyanide; ‘green’ technologies imply the use of alternate lixiviants such as ammoniacal thiosulfate and maybe to a certain extent thiourea or physical separation methods w/o the use of harmful chemicals…