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 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: A multi-stage froth flotation process is provided for concentrating sulphide minerals or middlings containing non-ferrous metal values such as nickel, cobalt and copper, which co-exist with significant amounts of pyrrhotite. The process is carried out without relying on any specific reagent as pyrrhotite depressant, but rather by exploiting the natural pulp environment with low REDOX potentials generated by mild steel grinding media in the grinding step preceding the froth flotation. The concentrate from the flotation stage(s) in which the REDOX potential rises above a predetermined value, is recycled back to the grinding step and/or to preceding flotation stage(s) from which concentrate is collected as the final product or is subjected to an up-grading in a further cleaning stage.

Abstract: This invention provides a process for improved separation of mono/multi-metallic sulphide minerals from significant amounts of iron sulphides, mainly pyrrhotite and/or their finely divided process middlings. The process comprises subjecting such material to a conditioning stage with at least one water-soluble sulphur-containing inorganic compound as a prerequisite step for further conditioning with nitrogen-containing organic chelating agents, preferably polyethylenepolyamines, prior to froth flotation wherein iron mineral, primarily pyrrhotite is depressed, thus allowing selective recovery of mono/multi-metallic minerals containing non-ferrous metal value(s).

Abstract: A method is provided for extracting at least one of the trivalent ions Fe and Al from an acid solution. The method comprises uniformly mixing the acid solution with a liquid organic extractant comprising an organophosphorus compound and an alkylaromatic sulfonic acid dissolved in a water-immiscible organic solvent, the extractant being selective to the solvent extraction of said trivalent ions under acidic conditions. The molar ratio of the sulfonic acid to the organophosphorus compound is controlled over a range of about 1:4 to 10:1 and the mixing carried out for a time sufficient to effect solvent extraction of said trivalent ions and provide a raffinate substantially impoverished in said trivalent ions and a loaded extractant containing said trivalent ions, following which the loaded extractant is separated from the raffinate.

Abstract: Nickeliferous sulfidic materials containing at least one other metal selected from the group consisting of cobalt, copper and iron are leached with an at least 3 N hydrochloric acid solution to produce a pregnant nickel chloride solution. The pregnant nickel chloride solution is treated with a liquid organic extractant to extract the other metals. The nickel chloride raffinate is concentrated with respect to nickel chloride, and the concentrated nickel chloride solution is heated to at least about 750.degree. C. to hydrolyze the nickel chloride to a refined nickel oxide product and a hydrogen chloride-containing gaseous effluent which is recycled to the concentration step and then through water to regenerate the leaching solution.

Abstract: Nickel and cobalt are separated from aqueous process solutions having pH values below about 4 and containing other metal ions by contacting the process solutions with liquid organic extractants containing a mixture of .alpha.-hydroxyoximes and sulfonic acids dissolved in water-immiscible organic solvents.

Abstract: Nickel values contained in oxidic ores are recovered by leaching with sulfuric acid. The ore is slurried with water, preheated to a leaching temperature between about 230.degree. C and about 300.degree. C and the preheated slurry is fed to one or more vigorously agitated autoclaves, operating continuously in series. Sulfuric acid is added incrementally to the preheated slurry to minimize the amount of iron and aluminum in solution until between about 0.15 part and about 0.8 part of acid per part of dry ore is added to the slurry, thereby minimizing the deposition of scale in the autoclaves.