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.

Abstract: The present invention is directed to a precious metal recovery process in which carbonaceous material, such as preg robbing carbon, is floated after sulfide oxidation to separate the carbonaceous material from the precious metal.

Abstract: The present invention is directed to a precious metal recovery process in which basic ferric sulphates and/or jarosites are controlled by hot curing of the autoclave discharge slurry followed by decomposition of argentojarosite using strong acid consumers.

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 invention is directed to a multi-compartment autoclave using inter-compartment dividers having one or more underflow openings for passing a feed stream between compartments.

Abstract: In the process of recovering platinum group metals from platinum group metal- and base metal-containing materials, the present invention uses reductants and a sulfur-deficient matte to aide the separation of the furnace matte from the furnace slag and therefore improve recovery of platinum group metals.

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: Embodiments of the present invention are directed to flotation of sulfidic materials following aerating by an oxidizing gas and contacting by a sulfoxy reagent.

Abstract: The present invention is directed to flotation of refractory gold sulfide ores in which the ore is ground, floated, the tailings reground, and refloated to produce gold-bearing concentrates.

Abstract: A method for suppressing mercury dissolution during pressure oxidation of precious metal-containing materials in the presence of halogens and halides is provided. Pressure oxidation is performed under controlled oxidative conditions to maintain the mercury predominantly in the solid residue.

Abstract: A method for recovering zinc ions by selective zinc sulfide precipitation from an aqueous solution comprising zinc ions and metal ions of a metal that precipitates as a metal sulfide at a pH lower than a pH at which zinc ions precipitate as a zinc sulfide.

Abstract: Precious metal recovery by thiosulfate leaching where thiosulfate lixiviant is generated in situ employing elemental sulfur generated from partial oxidation of sulfidic precious metal-bearing feed and/or employing reactants from processing effluent.

Abstract: The present invention is directed to recovery of gold from refractory and double refractory ores using a fungal agent and/or culture media.