Abstract: A multi-step process for recovering metal values from lead smelter matte. The matte is mixed with sulfuric acid and manganese oxide and leaching is effected at atmospheric pressure to form an aqueous solution including dissolved metal sulfates and a residue containing sulfur and lead sulfate. The sulfur is removable by conventional means and the lead sulfate may be returned to the smelter. The pH of the aqueous sulfate solution is adjusted to 3.5 to 4.5 to precipitate ferric iron and arsenic and pH is readjusted to about 3.0 to redissolve coprecipitated copper. After separation from the precipitate, the aqueous solution is mixed with a sulfiding agent, such as sodium sulfide at a pH of not more than 3 to selectively precipitate copper sulfide. After separating the copper sulfide, the aqueous solution is mixed with further sulfiding agent at a pH of 3 to 4.5 to form a cobalt-nickel sulfide precipitate in which the weight ratio of copper-nickel to sulfur is 1.8.

Abstract: A long-lived electrode is produced, for use in the electrowinning of metals, by electrodepositing a coating onto the electrode substrate. The coating has a uniform grain size and structure which is controlled by superimposing alternating current onto direct current during electrodeposition.

Abstract: This invention provides a method for treating manganese oxide ores in an aqueous medium, with hydrogen halide or sulfuric acid, and a hydrogen sulfide or a metal sulfide, e.g. an ore. A leach liquor containing the desirable metal halides is then separated from the solid, insoluble residue. Any iron value in either the manganese oxide ore or in any metal sulfide ore present is not dissolved or is converted to an insoluble iron oxide. Elemental sulfur is also obtained.The metal values in the leach liquor are recovered by crystallization of the manganese halide and liquid ion exchange extraction of the other metal values present.

Abstract: This invention provides a process for obtaining the nonferrous metal values from a manganese oxide ore, by reacting the ore with an aluminum halide or a ferric halide at a temperature of at least about 50.degree. C and preferably, at least about 130.degree. C. The manganese oxide ore can be treated with or without reduction. If reduction of the manganese oxide ore is desired, it can be accomplished prior to, or simultaneously with, the reaction with the aluminum halide or ferric halide.The resulting nonferrous metal halides can be separated from the reacted ore residue by conventional methods such as leaching or evaporation.