Abstract: The present disclosure is directed to a gold recovery process in which activated carbon or another carbon-based material is used to accelerate thiosulfate leaching of gold from a gold-bearing material. In some embodiments, the gold recovery process comprises providing particulate activated carbon or another carbon-based material, providing a precious metal-bearing material, contacting the precious metal-bearing material with the particulate carbon-based material, thiosulfate, an anion exchange resin, and an oxidant to form a slurry comprising a slurried precious metal-bearing material, and leaching a precious metal from the slurried precious metal-bearing material.

Abstract: The disclosure relates to pre-treatment of precious metal-bearing oxide ores, prior to precious metal leaching by thiosulfate. The process comprises mixing oxide ore in oxygenated water in the presence of a carbon-based material (e.g., activated carbon or other type of carbon). The carbon-based material can be separated from the ore slurry, and, the gold is thereafter leached by a thiosulfate lixiviant.

Abstract: The disclosure relates to pre-treatment of precious metal-bearing oxide ores, prior to precious metal leaching by thiosulfate. The process comprises mixing oxide ore in oxygenated water in the presence of a carbon-based material (e.g., activated carbon or other type of carbon). The carbon-based material can be separated from the ore slurry, and, the gold is thereafter leached by a thiosulfate lixiviant.

Abstract: The disclosure relates to pre-treatment of precious metal-bearing oxide ores, prior to precious metal leaching by thiosulfate. The process comprises mixing oxide ore in oxygenated water in the presence of a carbon-based material (e.g., activated carbon or other type of carbon). The carbon-based material can be separated from the ore slurry, and, the gold is thereafter leached by a thiosulfate lixiviant.

Abstract: A method and system are provided in which a gold and/or silver-collecting resin-in-leach circuit comprises both co-current and counter-current sections.

Abstract: The present invention relates to flotation of sulfidic copper-molybdenum- and gold-containing minerals. More specifically, the invention relates to sulfoxy reagent-assisted floatation for separating of sulfides of copper, molybdenum and gold from pyrite, marcasite, pyrrhotite, arsenopyrite, and other gangue minerals following aerating by an oxidizing gas and contacting by a sulfoxy reagent. To promote collection and flotation the feed mineral materials are preferably not contacted with an externally generated non-oxidizing gas to lower the dissolved molecular oxygen content prior to flotation.

Abstract: The disclosure relates to pre-treatment of precious metal-bearing oxide ores, prior to precious metal leaching by thiosulfate. The process comprises mixing oxide ore in oxygenated water in the presence of a carbon-based material (e.g., activated carbon or other type of carbon). The carbon-based material can be separated from the ore slurry, and, the gold is thereafter leached by a thiosulfate lixiviant.

Abstract: The disclosure relates to the oxidation and immobilization of trivalent arsenic from arsenic-containing solutions. The process includes oxidation of trivalent arsenic (As3+) species to the pentavalent state (As5+). A carbon additive (e.g., activated carbon) and oxygen are used to promote the arsenic oxidation processes. After oxidation of arsenic to the pentavalent state, the arsenic can be removed by precipitation to ferric arsenate or calcium arsenate or other arsenic containing compounds known in the art. The oxidation of arsenic can also occur simultaneously with the production and precipitation of ferric arsenate (e.g., scorodite). Ferrous iron can be oxidized to ferric iron in the presence of activated carbon and oxygen.

Abstract: A method and system are provided in which a gold and/or silver-collecting resin-in-leach circuit comprises both co-current and counter-current sections.

Abstract: The present invention relates to flotation of sulfidic copper- molybdenum- and gold-containing minerals. More specifically, the invention relates to sulfoxy reagent-assisted flotation for separating of sulfides of copper, molybdenum and gold from pyrite, marcasite, pyrrhotite, arsenopyrite, and other gangue minerals following aerating by an oxidizing gas and contacting by a sulfoxy reagent. To promote collection and flotation the feed mineral materials are preferably not contacted with an externally generated non-oxidizing gas to lower the dissolved molecular oxygen content prior to flotation.

Abstract: A method to recover gold lost in roaster calcine-leach tailings, due to the formation of cyanide refractory compounds or morphologies during the roasting process. The process can include acid leaching of magnetic concentrate from roaster leach tailings, combining the acid leach slurry to the pre-acidulation tank for pressure oxidation feed, acid pressure oxidation of the pressure oxidation feed, and recovery of gold.

Abstract: The present disclosure is directed to a process for recovering a precious metal from a pregnant leach solution using a resin extractant. The precious metal is eluted from the loaded resin using an eluant comprising trithionate. The barren resin is contacted with a sulfide, bisulfide, and/or polysulfide to convert sorbed trithionate to thiosulfate. The desorbed thiosulfate is contacted with an oxidant and converted to trithionate for eluant recycle.

Abstract: In an embodiment, the present invention relates to an apparatus and a process for producing a concentrated form of basic zinc sulphate from a, typically dilute, acidic zinc sulphate-bearing solution. The process embodiment comprises the steps of precipitating the zinc, preferably primarily as basic zinc sulphate, from the acidic zinc sulphate solution, preferably using calcium oxide, in such a way as to promote the formation of separate gypsum crystals and basic zinc sulphate particles, and upgrading the zinc content in the precipitates by separating the basic zinc sulphate from the gypsum using size separation techniques.

Abstract: A method and system are provided in which a gold and/or silver-collecting resin-in-leach circuit comprises both co-current and counter-current sections.

Abstract: A method to recover gold lost in roaster calcine-leach tailings, due to the formation of cyanide refractory compounds or morphologies during the roasting process. The process can include acid leaching of magnetic concentrate from roaster leach tailings, combining the acid leach slurry to the pre-acidulation tank for pressure oxidation feed, acid pressure oxidation of the pressure oxidation feed, and recovery of gold.

Abstract: The present invention is directed to a precious metal recovery process in which an acid sulfidic feed material is subjected to acid pressure oxidation and an alkaline sulfidic feed material is subjected to alkaline pressure oxidation, with the discharge slurries from the pressure oxidation processes being combined to reduce neutralization requirements prior to precious metal recovery.

Abstract: A method and system are provided in which a gold and/or silver-collecting resin-in-leach circuit comprises both co-current and counter-current sections.

Abstract: The present invention is directed to a precious metal recovery process in which an acid sulfidic feed material is subjected to acid pressure oxidation and an alkaline sulfidic feed material is subjected to alkaline pressure oxidation, with the discharge slurries from the pressure oxidation processes being combined to reduce neutralization requirements prior to precious metal recovery.

Abstract: The present disclosure is directed to a process for recovering a precious metal from a pregnant leach solution using a resin extractant. The precious metal is eluted from the loaded resin using an eluant comprising trithionate. The barren resin is contacted with a sulfide, bisulfide, and/or polysulfide to convert sorbed trithionate to thiosulfate. The desorbed thiosulfate is contacted with an oxidant and converted to trithionate for eluant recycle.

Abstract: The present invention is directed to flotation of refractory gold sulfide ores and to pressure oxidized residue neutralization using flotation tailings that have been contacted with an off gas of pressure oxidation.