Degussa Aktiengesellschaft

Degussa Atiengesellschaft

Andrew Griffiths

Roy Norcross

Helmut Knorre

M Quamrul Ahsan

Friedrich W Merz

Joachim Fischer

Juergen Loroesch

Stephen Gos

Ernest Haug

Gerhard Scherer

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.

Process for the leaching of gold and silver with cyanidic leaching

A process is disclosed for the detoxification of effluents containing cyanide by treating with a mixture of hydrogen peroxide and phosphoric acid.

Process for the removal of cyanide from wastewaters

Treatment of effluent containing cayanide is disclosed wherein a mixture of H.sub.2 SO.sub.4 and H.sub.2 O.sub.2 with between 0.01 and 0.5 moles of H.sub.2 SO.sub.4 per mole of H.sub.2 O.sub.2 is used.

Process for the treatment of effluents containing cyanide and other

A process for treating effluents contaiing cyanide from mining operations wherein magnetic separation is used prior to treatment with hydrogen peroxide.

Process for the detoxification of effluents from ore processing

A process for the treatment of aqueous effluent containing cyanide and toxic or heavy metals, wherein the effluent is contacted with a sufficient amount of hydrogen peroxide to oxidize at least a substantial portion of the cyanide in the effluent in the presence of sufficient trimercaptotriazine to react with a substantial portion of the metal present in said effluent, and precipitating said metal component.

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Ridgewood, NJ, United States of America

Andrew Griffiths