Process for the leaching of gold and silver with cyanidic leaching solution and controlled addition of hydrogen peroxide

US5275791A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Helmut Knorre · Seligenstadt, DE
• Andrew Griffiths · Ridgewood, US
• Juergen Loroesch · Hanau, DE
• Joachim Fischer · Rodgau, DE

Key dates

• Filing date: Jun 16, 1992
• Grant date: Jan 4, 1994
• Expiry date: Jun 16, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22B11/08
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A process is described for leaching gold and/or silver from ores or ore concentrates using an aqueous alkaline cyanide solution with addition of hydrogen peroxide. The addition of the aqueous H.sub.2 O.sub.2 solution is regulated and controlled through the concentration of the oxygen dissolved in the leaching solution, the leaching solution containing from 2 to 20 mg O.sub.2 and preferably from 7 to 13 mg O.sub.2 per liter. 0.5 to 5% by weight H.sub.2 O.sub.2 solutions are preferably added. The process is applicable both to leaching by agitation and to heap leaching, the addition of H.sub.2 O.sub.2 being regulated and controlled through measurement of the O.sub.2 concentration in the leaching solution and can also involve measurement in a measuring stream. Despite low consumptions of H.sub.2 O.sub.2 and NaCN, the gold yield is even increased in some cases and the leaching time shortened.