Abstract: An antimony recovery process is disclosed in which antimony-containing material is leached in a solvent including elemental sulfur and a caustic to preferentially leach antimony. The antimony-containing leach liquor from the leaching step is separated from the insoluble residue by filtration, and the antimony compounds in the separated leach liquor are crystallized to separate the antimony compounds from impurities which are left in solution in the leach liquor. The crystals are then redissolved and treated to create marketable antimony products of high purity, such as antimony metal, sodium hydroxy antimonate, sodium antimonate, antimony pentoxide, and antimony pentasulfide. Alternatively, the crystallized antimony compounds comprising primarily sodium thioantimonate crystals may be recovered and sold without further treatment. Waste products may be treated with soluble iron compounds and lime to render the waste products safe for disposal.

Abstract: Pressure leaching metal bearing mineral material such as silver and copper bearing mineral material, e.g. sulfide and/or oxide, with an aqueous liquid containing sulfuric acid and very low concentration nitric acid under oxygen pressure, to dissolve out the corresponding desired metal values from such mineral material with nitric acid regeneration;Acid pretreatment of such metal bearing mineral material by preliminary leaching with an aqueous liquid containing sulfuric acid and very low concentration nitric acid under normal ambient pressure, to dissolve substantially attendant acid soluble metal carbonate values, e.g.