Method for thiosulfate leaching of precious metal-containing materials
AssigneePlacer Dome Technical Services Limited
InventorsJinxing Ji, Christopher Andrew Fleming, Paul George West-Sells, Ralph Peter Hackl
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Abstract
Processes are provided for recovering precious metals from refractory materials using thiosulfate lixiviants. The processes can employ lixiviants that include at most only small amounts of copper and/or ammonia and operate at a relatively low pH, reduction of polythionates, inert atmospheres to control polythionate production, and electrolytic solutions which provide relatively high rates of precious metal recovery.
Claims74
A process for recovering a precious metal from a precious metal-containing material, comprising:
- (a) contacting the precious metal-containing material with a thiosulfate lixiviant at superatmospheric pressure in the substantial or complete absence of added ammonia to solubilize the precious metal and form a pregnant thiosulfate leach solution containing the solubilized precious metal;
- and
- (b) thereafter recovering the solubilized precious metal from the pregnant thiosulfate leach solution, wherein the total ammonia concentration in the thiosulfate lixiviant is less than about 0.05M.
A process for recovering a precious metal from a carbonaceous precious metal-containing material, comprising:
- (a) contacting the carbonaceous precious metal-containing material with a thiosulfate lixiviant in the substantial or complete absence of added copper and added ammonia to solubilize the precious metal and form a pregnant thiosulfate leach solution containing the solubilized precious metal;
- and
- (b) thereafter recovering the solubilized precious metal from the pregnant thiosulfate leach solution, wherein, in the contacting step, the thiosulfate lixiviant contains less than about 20 ppm of copper ion.
A process for recovering a precious metal from a precious metal-containing material, comprising:
- (a) contacting the precious metal-containing material with a thiosulfate lixiviant at superatmospheric pressure in the substantial or complete absence of at least one of added copper and added ammonia to solubilize the precious metal and form a pregnant thiosulfate leach solution containing the solubilized precious metal;
- and
- (b) thereafter recovering the solubilized precious metal from the pregnant thiosulfate leach solution, wherein in the contacting step the thiosulfate lixiviant contains less than about 20 ppm of copper ion.
A process for recovering a precious metal from a carbonaceous precious metal-containing material, comprising:
- (a) contacting the carbonaceous precious metal-containing material with a thiosulfate lixiviant in the substantial or complete absence of added copper and added ammonia to solubilize the precious metal and form a pregnant thiosulfate leach solution containing the solubilized precious metal;
- and
- (b) thereafter recovering the solubilized precious metal from the pregnant thiosulfate leach solution, wherein the total ammonia concentration in the thiosulfate lixiviant is less than about 0.05M.
Dependencies are inferred from the claim text.