Barrick Gold Corporation
METHOD FOR RECOVERING PRECIOUS METALS FROM THIOSULFATE LEACH SOLUTIONS

Abstract:

The present disclosure is directed to a process for thiosulfate leaching of a precious metal-containing material and recovering a precious metal from a pregnant leach solution using a resin extractant. The precious metal is eluted from the loaded resin optionally using an eluant comprising trithionate. Various process improvements include maintaining the thiosulfate-containing leach solution substantially free of thiols and amines, maintaining a concentration of a sulfide in the thiosulfate leach solution of no more than about 100 ppm, recycling the barren resin free of contact with a sulfide, bisulfide, and polysulfide, and/or maintaining a concentration of tetrathionates, trithionates, sulfur-oxygen anions, and/or combinations thereof within about 50% of a concentration level of the one or more of tetrathionates, trithionates, sulfur-oxygen anions, the combinations thereof in the precious metal-containing solution before contact with the recycled barren resin.