Abstract: A method for treating a mineral composition containing iron, arsenic or other Group VA compounds comprises milling the mineral composition to a particle size of P80 of less than 25 ?m and leaching the mineral composition in the presence of lime and/or limestone and a soluble alkali complexing agent and in the presence of an oxygen containing gas at a pH in the range of from 3.5 to 6.

Abstract: A method for treating a mineral composition containing iron, arsenic or other Group VA compounds comprises milling the mineral composition to a particle size of P80 of less than 25 ?m and leaching the mineral composition in the presence of lime and/or limestone and a soluble alkali complexing agent and in the presence of an oxygen containing gas at a pH in the range of from 3.5 to 6.

Abstract: A process for treating a mixed sulphidic material containing lead sulphide and at least one other metal sulphide. The process includes the steps of subjecting the mixed sulphidic material to selective oxidation such that lead sulphide in the material is oxidised to form an oxidized lead compound while substantial oxidation of the at least one other metal sulphide is avoided, and separating the oxidized lead compound from the at least one other metal sulphide. The oxidized lead compound may be separated by flotation wherein the oxidized lead compound reports to the tailings and the at least one other metal sulphide reports to the concentrate (froth).

Abstract: A process for treating a mixed sulphidic material containing lead sulphide and at least one other metal sulphide. The process includes the steps of subjecting the mixed sulphidic material to selective oxidation such that lead sulphide in the material is oxidised to form an oxidised lead compound while substantial oxidation of the at least one other metal sulphide is avoided, and separating the oxidized lead compound from the at least one other metal sulphide. The oxidized lead compound may be separated by flotation wherein the oxidized lead compound reports to the tailings and the at least one other metal sulphide reports to the concentrate (froth).

Abstract: A method of processing a mineral composition comprising a refractory material the method comprising milling the composition to a particle size of P80 of less than 25 microns and leaching said composition with a solution comprising lime and/or limestone in the presence of an oxygen containing gas.

Abstract: Anhydrous magnesium chloride is prepared by a process in which hydrated magnesium chloride (10) is mixed in a vessel (11) with ethylene glycol (12). The mixture (13) is dehydrated in distillation columns (14, 15 and 16) with the dehydrated ethylene glycol magnesium chloride solution (20) pumped into a crystalliser (21) simultaneously with the separate addition of anhydrous ammonia gas (22) to the crystalliser (21). Prior to the introduction of reactants (20 and 22), the crystalliser (21) contains ethylene glycol saturated with ammonia. A crystalliser slurry of magnesium chloride hexammoniate (23) is continuously pumped from the crystalliser (21) into a pressure filter (24) where the crystals are washed with methanol saturated with ammonia (26). The washed crystals (27) are transferred to a fluidised bed calciner (28) where methanol is evaporated from the crystals at 120.degree. C. and thereafter the crystals are calcined to anhydrous magnesium chloride at 450.degree. C.

Abstract: A method is provided for processing a sulphide mineral composition which at least partly comprises an iron-containing mineral.