Claims
- 1. 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 and gold;
- (b) optionally removing and recovering substantially all gold, if present, from the pregnant leach solution or pulp;
- (c) contacting the resulting solution or pulp with an anion exchange resin thereby adsorbing copper cyanide at a CN:Cu ratio of <3:1 and gold cyanide, if present, onto the resin;
- (d) separating the resin having copper cyanide and gold cyanide, if present, adsorbed thereon from the now depleted solution or pulp containing no copper, gold or cyanide;
- (e) treating the loaded resin obtained in step (d) above with an eluant containing copper cyanide at a CN:Cu ratio of between 3.5:1 and 4:1 and a copper concentration of at least 10 grams/liter thereby partially eluting copper cyanide and gold cyanide, if present, from the resin and producing an eluate having a CN:Cu ratio of less than 4:1; and
- (f) electrowinning copper metal and gold metal, if present, from the eluate produced in step (e).
- 2. The process of claim 1 wherein the eluted resin obtained in step (e) is converted to a form suitable for use in step (c) by treating the eluted resin with acid thereby precipitating CuCN in the pores of the resin.
- 3. The process of claim 1 wherein electrowinning of copper is carried out by
- (a) passing the eluate as the catholyte through a compartment containing the cathode(s);
- (b) plating copper metal and gold metal, if present, on the surface of the cathode(s) in an electrowinning cell wherein the anode(s) are optionally kept isolated from the catholyte by a cation exchange membrane thereby preventing anodic oxidation of cyanide ions; and
- (c) recovering copper from the cathode(s) by stripping the cathode surfaces or by smelting and gold, if present, by electrorefining.
- 4. The process of claim 1 wherein said pregnant leach solution or pulp resulting from step (b) is treated in a process comprising the steps of:
- (a) treating the solution or pulp with regenerated resin thereby reducing the CN:Cu ratio to approximately 3:1;
- (b) separating the resin from the now partially CN-depleted solution or pulp; and
- (c) processing the resulting solution or pulp according to steps (c)-(f) of claim 1.
- 5. The process of claim 4 wherein the resin obtained in step (b), containing free cyanide, is treated with acid to produce regenerated resin useful in step (a).
- 6. A process of treating waste streams containing cyanide ions but little or no copper comprising the steps of:
- (a) treating said streams with regenerated resin thereby extracting substantially all cyanide ions;
- (b) separating the resin from the now CN-depleted solution; and
- (c) treating the resin with acid to produce regenerated resin.
- 7. The process of claim 1 wherein the electrowinning of copper is carried out by:
- (a) passing the eluate as the catholyte through a compartment containing the cathode(s);
- (b) plating copper metal on the surface of the cathode(s) in an electrowinning cell wherein the anode(s) are kept isolated from the catholyte by a cation exchange membrane thereby preventing anodic oxidation of cyanide ions; and
- (c) recovering copper from the cathode(s) by stripping from the cathode surfaces or by smelting.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of copending application Ser. No. 08/533,984, filed Sep. 26, 1995, which was a continuation-in-part of application Ser. No. 08/376,367, filed Jan. 23, 1995, now abandoned, which was a continuation-in-part of application Ser. No. 08/217,912, filed Mar. 25, 1994, now U.S. Pat. No. 5,411,575.
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Continuation in Parts (3)
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Number |
Date |
Country |
Parent |
533984 |
Sep 1995 |
|
Parent |
376367 |
Jan 1995 |
|
Parent |
217912 |
Mar 1994 |
|