Oxidation/reduction process for recovery of precious metals from MnO.sub.2 ores, sulfidic ores and carbonaceous materials

A process for recovery of precious metals from a precious metal-containing refractory ore or other refractory feed comprising precious metals including at least material selected from the group consisting of silver and gold, comprising the steps of:

• adding a material to said feed selected from the group consisting of MnO.sub.2, a reductant, or mixtures thereof, said reductant comprising material selected from the group consisting of pyrite, sulfidic materials and carbonaceous materials;
• leaching said feed to form a leach with a leach liquor comprising an acid selected from the group consisting of HCl and H.sub.2 SO.sub.4 in the presence of MnO.sub.2 and a reductant comprising material selected from the group consisting of pyrite, sulfidic materials and carbonaceous materials wherein said reductant reduces said MnO.sub.2 that is associated with precious metals;
• adding a source of chloride ion to said leach to maintain a concentration of chloride ions in said leach sufficient to dissolve at least about 50% of said precious metals present in said ore;
• separating a portion of said leach comprising at least a portion of said dissolved precious metals and further comprising a chloride carrier which comprises MnCl.sub.2 to produce a removed portion of said leach liquor;
• recovering a solid comprising at least a portion of said precious metals from said removed portion to produce a precious metals-depleted stream;
• and
• recycling at least a portion of said chloride carrier to said leaching step to carry chloride values to the leach.