Recovery of precious metals from refractory low-grade ores
AssigneeAmax Inc.
InventorsGopalan Ramadorai, Mahesh C. Jha, Marcy J. Kramer
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Abstract
Low-grade refractory gold ores, which may also contain silver and other metal values are treated by partial roasting of concentrate to remove controlled amounts of sulfur and carbon, then oxygen pressure leached to oxidize further amounts of sulfur and carbon and to dissolve base metals and a portion of any silver present, and the residue is then cyanided to dissolve gold and remaining silver which are then recovered.
Claims8
The process for treating a refractory low-grade ore containing precious metals from the group consisting of gold and silver to recover the precious metal content thereof which comprises partially roasting a concentrate of said ore to oxidize a major portion of sulfur present to sulfur dioxide but to oxidize a minor portion only of carbon present therein, subjecting the partially roasted calcine to an oxygen pressure leach to oxidize remaining sulfur and carbon, to decompose any ferrites present and to dissolve base metals and some silver, and then subjecting the residue from said oxygen pressure leach to cyanidation to dissolve substantially all the precious metals present therein.
Dependencies are inferred from the claim text.