Hydrometallurgical extraction and recovery of copper, gold, and silver via cyanidation and electrowinning
AssigneeE. I. Du Pont de Nemours and Company
InventorsChristopher Andrew Fleming, Walther G. Grot, John Anton Thorpe
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Abstract
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.
Claims11
A hydrometallurgical extraction process for treating copper feed materials comprising the steps of:
- (a) treating said feed materials with an aqueous cyanide solution having a molar ratio of CN:Cu of >3 thereby simultaneously leaching copper, gold and/or silver;
- (b) optionally removing and recovering substantially all gold or silver, if present, from the pregnant leach solution;
- and
- (c) removing and recovering copper from the solution resulting from step (b) by an electrowinning process in an electrowinning cell wherein high current efficiencies are achieved at high current densities and at low copper concentrations by
- (i) passing the solution as the electrolyte (catholyte) through a compartment containing the cathode(s) with a high rate of flow of the catholyte, wherein the cathode has high surface area, and wherein the CN:Cu molar ratio of the catholyte is .ltoreq.4.5:1;
- (ii) electrodepositing copper metal on the surface of the cathode(s) in the cell wherein oxidation of cyanide ions at the anode is diminished;
- and
- (iii) recovering the copper from the cathode(s) by electrorefining or by smelting.
A process for the direct recovery of copper by electrowinning in an electrowinning cell from a solution containing copper cyanide (and optionally containing gold or silver or both) wherein high current efficiencies are achieved at high current densities and at low copper concentrations comprising the steps of:
- (a) passing the solution as the electrolyte (catholyte) through a compartment containing the cathode(s) with a high rate of flow of the catholyte, wherein the cathode has high surface area, and wherein the CN:Cu molar ratio of the catholyte is .ltoreq.4.5:1;
- (b) electrodepositing copper metal on the surface of the cathode(s) in an electrowinning cell wherein oxidation of cyanide ions at the anode is diminished;
- and
- (c) recovering copper from the cathode(s) by electrorefining or by smelting.
Dependencies are inferred from the claim text.