The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 05, 1993
Filed:
Jun. 18, 1992
Helmut Knorre, Seligenstadt, DE;
Juergen Loroesch, Hanau-Steinheim, DE;
Steven Gos, Hanau, DE;
Mathias Stoll, Steinau-Marjoss, DE;
Annette Ziegler, Offenbach, DE;
Degussa Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
A process for leaching gold and silver from ores and ore concentrates is disclosed using a cyanide leaching solution and hydrogen peroxide and maintaining an oxygen concentration of 2 to 20 Mg of O.sub.2 /liter. In the invention, leaching takes place in the presence of decomposition catalysts and preferably the formed cyano-complexes are separated during leaching from the leach solution. Decomposition catalysts are manganese compounds, present as 0.01 to 1 mg computed as Mn/liter of barren solution, or 1 to 50 mg computed as Mn per kg of ore slurry, or they are inorganic or organic polymers or carbon. Activated charcoal is preferred and simultaneously adsorbing cyano-complexes of precious metals. The process offers lowered consumption of H.sub.2 O.sub.2 and possibly cyanide and maximum gold yield in a shortened leaching time.