Patent ID: 8262768
Filing Date: 2012-09-11
Classification: B03D,C22B,Y02P

Abstract:
1. A method, comprising: (a) providing a feed material comprising a precious metal, at least about 0.1 wt. % sulfide sulfur, and 0.3 to about 10 wt. % carbonaceous materials; (b) oxidizing at least a portion of the sulfide sulfur in the feed material to provide an oxidized material, wherein at least most of the gold and/or silver and carbonaceous materials remain in the oxidized feed material; (c) comminuting the oxidized material to remove, at least partially, an oxidative film on at least some particles of the oxidized feed material; (d) after step (b), floating the comminuted and oxidized feed material to separate the material into a first fraction comprising at least most of the gold and/or silver and a second fraction comprising at least about 25 wt. % of the carbonaceous materials in the feed material, wherein the comminuted and oxidized feed material is free of precious metal leaching prior to the floating step; (e) comminuting the second fraction to provide a comminuted second fraction; (f) floating the comminuted second fraction to form cleaner tails comprising most of the gold and/or silver in the comminuted second fraction and a cleaner concentrate comprising most of the carbonaceous material in the comminuted second fraction; and (g) after floating is completed, thereafter recovering the gold and/or silver from the first fraction and the cleaner tails, wherein the first fraction and the cleaner tails comprise at least about 90% of the gold and/or silver in the oxidized material.