Abstract: Disclosed herein is a method for easily and efficiently removing manganese from an aqueous acidic solution of sulfuric acid containing cobalt and manganese at low cast to obtain a high-purity cobalt sulfate aqueous solution usable as a raw material for lithium ion secondary batteries. The high-purity cobalt sulfate aqueous solution is obtained by mixing an aqueous acidic solution of sulfuric acid containing cobalt and manganese (aqueous phase) with an acidic organic extractant (organic phase) while adjusting the pH of the aqueous acidic solution of sulfuric acid to a value in a range between 2 and 4 with a pH adjuster such as sodium hydroxide to extract manganese into the organic phase. The acidic organic extractant to be used is preferably diluted so that the concentration of di-2-ethylhexyl phosphate is 10 to 30 vol %.

Abstract: A hydrometallurgical plant for nickel laterite ore extraction having a plurality of treatment facility lines wherein the plant is capable of minimizing a decrease in throughput when line failure occurs and efficiently restoring normal operation status Each line of the treatment facility includes a pretreatment step, a leaching step, a solid-liquid separation step, a neutralization step, a zinc removal step, a sulfurization step and a detoxification step. The lines are coupled by pipelines, each having a valve, installed after the solid-liquid separation step for sending a liquid from the solid-liquid separation step to the neutralization step in each line and/or after the sulfurization step for sending a liquid from the sulfurization step to the detoxification step in each line.

Abstract: Disclosed herein is a method for easily and efficiently removing manganese from an aqueous acidic solution of sulfuric acid containing cobalt and manganese at low cast to obtain a high-purity cobalt sulfate aqueous solution usable as a raw material for lithium ion secondary batteries. The high-purity cobalt sulfate aqueous solution is obtained by mixing an aqueous acidic solution of sulfuric acid containing cobalt and manganese (aqueous phase) with an acidic organic extractant (organic phase) while adjusting the pH of the aqueous acidic solution of sulfuric acid to a value in a range between 2 and 4 with a pH adjuster such as sodium hydroxide to extract manganese into the organic phase. The acidic organic extractant to be used is preferably diluted so that the concentration of di-2-ethylhexyl phosphate is 10 to 30 vol %.

Abstract: In a hydrometallurgical plant of a nickel laterite ore having a plurality of lines of treatment facilities, the hydrometallurgical plant of the nickel laterite ore which is, even when a serious trouble will occur in said treatment facilities, capable of minimizing decrease in throughput caused by this, and restoring a normal operation state early, after eliminating the serious trouble, and an operation method thereof. A hydrometallurgical plant of a nickel laterite ore having a plurality of lines, as treatment facilities including a pretreatment step, a leaching step, a solid-liquid separation step, a neutralization step, a zinc removal step, a sulfurization step and a detoxification step as one line, wherein a coupling pipeline having a valve is installed between a liquid sending pipeline from the solid-liquid separation step to the neutralization step in each line and/or between a liquid sending pipeline from the sulfurization step to the detoxification step in each line.

Abstract: Disclosed herein is a method for concentrating gold contained in a leach residue obtained in a copper hydrometallurgical process for recovering copper from a copper sulfide mineral to efficiently separate and recover gold from the leach residue: a gold-bearing copper sulfide mineral is subjected to pressure leaching with sulfuric acid at a temperature higher than 102° C. and 112° C. or lower to obtain a leach residue, and the leach residue is subjected to flotation to separate it into a float fraction and a sink fraction; the float fraction obtained by flotation is desulfurized to obtain a desulfurized product; the desulfurized product is subjected to oxidative roasting to obtain an oxidatively-roasted product; the oxidatively-roasted product is dissolved in a sulfuric acid solution to obtain a copper solution, and a gold-bearing residue is separated and recovered from the copper solution.

Abstract: Disclosed herein is a method for concentrating gold contained in a leach residue obtained in a copper hydrometallurgical process for recovering copper from a copper sulfide mineral to efficiently separate and recover gold from the leach residue. According to the method, a gold-bearing copper sulfide mineral is subjected to pressure leaching with sulfuric acid at a temperature higher than 102° C. and 112° C. or lower to obtain a leach residue, and the leach residue is subjected to flotation to separate it into a float fraction and a sink fraction. The float fraction obtained by flotation is desulfurized by heating at a temperature of 250 to 800° C. under an inert atmosphere to obtain a desulfurized product. The desulfurized product is subjected to oxidative roasting by heating at a temperature of 600 to 800° C. under an atmosphere of flowing oxygen or air to obtain an oxidatively-roasted product.

Abstract: A method of efficient separation/purification for obtaining high-purity silver chloride which eliminates the necessity of a pretreatment of a refining intermediate comprising sparingly soluble silver compounds and impurity elements when silver chloride is separated from the refining intermediate and purified to a high degree and which enables the silver chloride to be used as a raw material to give high-purity silver metal without necessitating the pyrometallurgical refining or electro-refining of the silver metal.

Abstract: A process for mutual separation of platinum group metals (PGM), wherein highly stable compounds and steps are used to efficiently remove impurity elements while preventing increase of impurity content relative to that of the PGM in the mother liquor and also preventing decomposition of a chloro complex, and palladium, platinum, iridium, ruthenium and rhodium are separated mutually in such a way that each of the separated PGM has a sufficient purity to be a commercial product.

Abstract: A method of efficient separation/purification for obtaining high-purity silver chloride which eliminates the necessity of a pretreatment of a refining intermediate comprising sparingly soluble silver compounds and impurity elements when silver chloride is separated from the refining intermediate and purified to a high degree and which enables the silver chloride to be used as a raw material to give high-purity silver metal without necessitating the pyrometallurgical refining or electro-refining of the silver metal.

Abstract: A process for mutual separation of platinum group metals (PGM), wherein highly stable compounds and steps are used to efficiently remove impurity elements while preventing increase of impurity content relative to that of the PGM in the mother liquor and also preventing decomposition of a chloro complex, and palladium, platinum, iridium, ruthenium and rhodium are separated mutually in such a way that each of the separated PGM has a sufficient purity to be a commercial product.