MONTREAL – Dundee Sustainable Technologies (DST) has achieved gold extraction 14% higher than cyanidation during the demonstration program of its proprietary cyanide-free gold recovery method. The demonstration plant is located in Thetford Mines, QC.
The program involved processing 170 tonnes of a gold- and copper-bearing refractory pyrite concentrate from a region where cyanide use is restricted. The DST process achieved results up to 90% gold recovery.
DST confirmed the efficiencies of the plant components, especially the oxidation circuit that removed 99% of the sulphide content while producing on-spec sulphuric acid that was shipped to a client. The chlorination circuit delivered the anticipated copper and gold recoveries, both of which were higher than cyanidation on the same samples. The demonstration program also proved that closed circuit operation with recycling and regeneration of the reagents is efficient. All solid residues met environmental requirements, added the company.
DST will use the plant this year to treat gold concentrates from selected sites to generate technical-economic studies with which to predict capital and operating expenses for a commercial plant.
The DST extraction process is explained at www.DundeeTechnologies.com.