Patent ID: 7559974
Filing Date: 2009-07-14
Classification: C22B,Y02P

Abstract:
1. A process for recovering a precious metal from a sulfidic precious metal-containing material, comprising: (a) at least partially oxidizing sulfidic sulfur in the material to form an oxidized precious metal-containing material; (b) contacting the oxidized precious metal-containing material with a thiosulfate leach solution to dissolve the precious metal and form a pregnant thiosulfate leach solution containing dissolved precious metal; (c) after the contacting step (b), maintaining a dissolved molecular oxygen content in at least one of the thiosulfate leach solution and the pregnant thiosulfate leach solution at or below about 1 ppm to inhibit the formation of trithionate and tetrathionate; and (d) recovering the dissolved precious metal from the pregnant thiosulfate leach solution.