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: 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 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: 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: An apparatus and a process for producing zinc oxide from a zinc-bearing material are provided. The process comprises the steps of leaching the complex sulfide material with hydrochloric acid, ferric chloride, and oxygen; precipitating iron from the leach solution using lime and oxygen; removing copper, silver, cadmium, cobalt and lead from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using lime; and regenerating HCl from a calcium chloride leach filtrate solution to regenerate hydrochloric acid and precipitate gypsum. Related processes for recovering copper, silver, lead, and iron from complex sulfide materials and for recovering lead from residue by solubilizing lead chloride and precipitating it with lime are also provided.

Abstract: The present invention relates to an apparatus and a process for producing zinc oxide from a zinc-bearing material. The process according to the present invention comprises the steps of leaching the complex sulfide material with hydrochloric acid and oxygen; precipitating iron from the leach solution using magnesium oxide and oxygen; removing copper, silver, cadmium, cobalt and lead from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using magnesium oxide; and spray roasting the remaining magnesium chloride leach solution to regenerate hydrochloric acid and magnesium oxide. The present invention further relates to processes for recovering copper, silver, lead, and iron from complex sulfide materials.