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: 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 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.

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: 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: 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: 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 relates to an apparatus and a process for producing zinc oxide from an acid soluble zinc-bearing material. The process according to the present invention comprises the steps of leaching the zinc oxide material with sulphuric acid; precipitating iron and silica from the leach solution using calcium oxide; removing copper, cadmium and cobalt from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using calcium oxide; and upgrading zinc content in zinc oxide precipitates by separating zinc oxide from gypsum using a flotation or granulometric sizing technique.

Abstract: The present invention relates to an apparatus and a process for producing zinc oxide from an acid soluble zinc-bearing material. The process according to the present invention comprises the steps of leaching the zinc oxide material with sulphuric acid; precipitating iron and silica from the leach solution using calcium oxide; removing copper, cadmium and cobalt from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using calcium oxide; and upgrading zinc content in zinc oxide precipitates by separating zinc oxide from gypsum using a flotation or granulometric sizing technique.