A method for recovering at least cobalt of valuable metals, cobalt and nickel, from an acidic solution obtained by subjecting waste containing positive electrode materials for lithium ion secondary batteries to a wet process, the acidic solution comprising cobalt ions, nickel ions and impurities, wherein the method includes: a first extraction step for Co recovery, the first extraction step being for extracting cobalt ions by solvent extraction from the acidic solution and stripping the cobalt ions; an electrolytic step for Co recovery, the electrolytic step being for providing electrolytic cobalt by electrolysis using a stripped solution obtained in the first extraction step for Co recovery as an electrolytic solution; a dissolution step for Co recovery, the dissolution step being for dissolving the electrolytic cobalt in an acid; and a second extraction step for Co recovery, the second extraction step being for extracting cobalt ions by solvent extraction from a cobalt dissolved solution obtained in the dissolution step for Co recovery and stripping the cobalt ions.

Provided is a method for producing nickel sulfide from an acidic sulfuric acid solution containing nickel, which is capable of suppressing particle diameters of nickel sulfide obtained thereby. The present invention is a method for producing nickel sulfide by causing a sulfurization reaction by blowing a hydrogen sulfide gas into an acidic sulfuric acid solution containing nickel, wherein: nickel sulfide having particle diameters of 5-20 m and serving as seed crystals is added into an acidic sulfuric acid solution having a nickel concentration of 0.5-5.0 g/L in an amount of 40-500% by mass relative to the amount of nickel contained in the acidic sulfuric acid solution; and a hydrogen sulfide gas is blown into the acidic sulfuric acid solution, into which the seed crystals have been added, while setting the amount of the hydrogen sulfide gas blown in to be within the range of 0.30-0.85 Nm.sup.3/kg-Ni.

The invention relates to a method for regenerating the extractive potential of an organic hydroxyoxime-based extraction solution used in the recovery of metals by liquid-liquid extraction. The method is two-stage, in which a solid hydroxylamine is used in the reaction stage, and the removal of the undesirable compounds generated in the reaction occurs in the second stage by adsorption purification. The method of the invention is suitable for treatment of degraded oxime metal extractants in various process organic solutions both in aldehyde and ketoxime extractant solutions. The method can also be used to treat a mixture of degraded oxime extractants.

Provided is a method for producing nickel sulfide from an acidic sulfuric acid solution containing nickel, which is capable of suppressing particle diameters of nickel sulfide obtained thereby. The present invention is a method for producing nickel sulfide by causing a sulfurization reaction by blowing a hydrogen sulfide gas into an acidic sulfuric acid solution containing nickel, wherein: nickel sulfide having particle diameters of 5-20 m and serving as seed crystals is added into an acidic sulfuric acid solution having a nickel concentration of 0.5-5.0 g/L in an amount of 40-500% by mass relative to the amount of nickel contained in the acidic sulfuric acid solution; and a hydrogen sulfide gas is blown into the acidic sulfuric acid solution, into which the seed crystals have been added, while setting the amount of the hydrogen sulfide gas blown in to be within the range of 0.30-0.85 Nm.sup.3/kg-Ni.

Various examples disclosed relate to methods for recycling lithium-ion battery cathode materials. The present disclosure includes methods that use ionic liquids, such as containing tetrachloroaluminate anions, or organic solutions of aluminum chloride, for recycling.

The present invention addresses the problem of providing a method for producing nickel microparticles in which the ratio of crystallite's diameter to the particle diameter of the nickel microparticles is controlled. At least two types of fluids to be processed are used, including a nickel compound fluid in which a nickel compound is dissolved in a solvent, and a reducing agent fluid in which a reducing agent is dissolved in a solvent. Sulfate ions are included in the nickel compound fluid, and polyol is included in the nickel compound fluid and/or the reducing agent fluid. The fluid to be processed is mixed in a thin film fluid formed between at least two processing surfaces (1, 2), at least one of which rotates relative to the other, and which are disposed facing each other and capable of approaching and separating from each other, and nickel microparticles are precipitated. The present invention is characterized in that at this time, the ratio (d/D) of crystallite's diameter (d) to the particle diameter (D) of the nickel microparticle is controlled by controlling the pH of the nickel compound fluid introduced between the processing surfaces (1, 2) and the molar ratio of sulfate ions with respect to nickel in the nickel compound fluid.

The invention addresses the problem of providing a method for producing microparticles. Provided is a method for producing microparticles. For the first process, seed microparticles are separated in a thin film fluid that forms between at least two processing surfaces, which are disposed facing each other, which can approach or separate from each other and at least one of which rotates relative to the other, and the fluid comprising the separated seed microparticles is discharged as a discharge fluid. Subsequently, for the second process, the separated seed microparticles are grown in the discharged discharge fluid to obtain the intended microparticles. Uniform and homogeneous microparticles are obtained as a result of the microparticle producing method comprising the two process.

A process and an apparatus are disclosed for improved recovery of metal from hot and cold dross, wherein a dross-treating furnace is provided with a filling material with good capacity to store heat. This filling material is preheated to a desired temperature by injection of an oxidizing gas to burn non-recoverable metal remaining in the filling material after tapping of the recoverable metal contained in the dross and discharging of the treatment residue. When dross is treated in such furnace, the heat emanating by conduction from the filling material is sufficient to melt and separate the recoverable metal contained in the dross, without addition of an external heat source, such as fuel or gas burners, plasma torches or electric arcs and without use of any salt fluxes. Furthermore, the recovered metal being in the molten state can be fed to the molten metal holding furnace without cooling the melt; in addition, the non-use of fluxing salt for the treatment means that the non-contaminated residue can be used as a cover for the electrolytic cells in the case of aluminum. In the case of zinc dross, the residue is a valuable zinc oxide by-product very low in contaminants.

Proposed is a method of extracting a metal from a salt solution derived from a spent battery, the method including preparing a salt solution derived from a spent battery containing metal ions, preparing a metal extractant mixture including a metal extractant and a metal extractant activator, bringing the metal extractant mixture into contact with the salt solution to produce a complex compound of the metal extractant mixture and the metal, and a first filtrate. The method further comprises recovering the complex compound and the first filtrate and bringing an acid into contact with the complex compound to produce a metal salt, and a second filtrate, recovering the metal salt and the second filtrate, and recovering each of the activator and acid from the first filtrate through electrodialysis.

Disclosed is a precipitation system for hydrometallurgical processing of laterite nickel ore, comprising a reaction tank, a feeding assembly, and a discharging assembly. Inside the reaction tank, there is a holding chamber; the feeding assembly comprises a first inlet pipe and a second inlet pipe; the discharging assembly comprises a material lifting pipe and a gas conduit; the gas conduit extends into the material lifting pipe below the liquid level. By introducing gas into the material lifting pipe through the gas conduit, bubbles are entrained in the solid-liquid mixture within the material lifting pipe, the liquid level within the material lifting pipe rises, ultimately causing the solid-liquid mixture at the bottom of the holding chamber to be discharged through the material lifting pipe. This allows for the direct extraction of precipitates from the bottom of the holding chamber, extending the period between manual cleanings of the reaction tank.