PROCEDURE FOR LEACHING PRECIOUS METALS USING A CYANIDE-CONTAINING LEACHING SOLUTION AND HYDROGEN PEROXIDE

摘要

ABSTRACTA process for leaching gold and silver from ores and oreconcentrates is disclosed using a cyanide leaching solutionand hydrogen peroxide and maintaining an oxygen concentrationof 2 to 20 Mg of O2/liter. In the invention, leaching takesplace in the presence of decomposition catalysts andpreferably the formed cyano-complexes are separated duringleaching from the leach solution. Decomposition catalystsare manganese compounds, present as 0.01 to 1 mg computed asMn/liter of barren solution, or 1 to 50 mg computed as Mn perkg of ore slurry, or they are inorganic or organic polymersor carbon. Activated charcoal is preferred andsimultaneously adsorbing cyano-complexes of precious metals.The process offers lowered consumption of H2O2 and possiblycyanide and maximum gold yield in a shortened leaching time.