E.i. Dupont De Nemours and Company

Lakefield Research Limited

Prime Resources Group Inc.

Christopher A Fleming

Walther G Grot

John Anton Thorpe

Alfred S Hayden

Chandulal P Patel

Briefly stated, there is provided a method for reducing cyanide consumption in precious metals mining extraction processes involving a sulfur bearing ore body, comprising the steps of providing a precious metal bearing material having intermediate sulfur oxidation products, and exposing the material to sulfur dioxide gas, bisulfite ions or sulfite ions, in a manner to cause at least a portion of the intermediate sulfur oxidation products to be rendered unreactive with cyanide.

Methods for reducing cyanide consumption in precious metal recovery by reducing the content of intermediate sulfur oxidation products therein

A hydrometallurgical process for treating copper feed materials containing gold and/or silver by simultaneously leaching copper, gold and/or silver into an aqueous cyanide solution, extracting copper, gold and cyanide with anion exchange resin is provided.

Hydrometallurgical extraction process

A hydrometallurgical process for treating copper feed materials containing gold and/or silver by simultaneously leaching copper, gold and/or silver into an aqueous cyanide solution, recovering copper in metallic form by electrowinning and regenerating cyanide ions is provided, wherein high current efficiencies are achieved at high current densities and at low copper concentrations.

Hydrometallurgical extraction and recovery of copper, gold, and silver

A hydrometallurgical process for treating copper ores or concentrates containing gold by simultaneously leaching both copper and gold into an aqueous cyanide solution, recovering copper and gold in metallic form by electrowinning or cementation and regenerating cyanide ions is provided.

Increased efficiency of extraction of silver and gold from ore materials thereof containing active carbonaceous material is obtained by conducting the extraction in two stages. In a first stage a portion of the silver and of the gold when present is extracted in a cyanide leach solution. The leached solids residue is contacted with activated carbon so that the silver and the gold when present are adsorbed on the activated carbon at elevated temperature (most preferably at about 35.degree. C. to about 100.degree. C.). In a modification, a slurry of the ore material is treated with cyanide and the precious metal adsorbed directly from the cyanided slurry with activated carbon at elevated temperature up to about 70.degree. C.

Growing community of inventors

Peterborough, Canada

Christopher A Fleming