Abstract: A method for producing mixed metal salts containing manganese ions and at least one of cobalt ions and nickel ions, the method including: an Al removal step of subjecting an acidic solution containing at least manganese ions and aluminum ions, and at least one of cobalt ions and nickel ions, to removal of the aluminum ions by extracting the aluminum ions into a solvent, the acidic solution being obtained by subjecting battery powder of lithium ion batteries to a leaching step; and a precipitation step of neutralizing an extracted residual liquid obtained in the Al removal step under conditions where a pH is less than 10.0, to precipitate mixed metal salts comprising a metal salt of manganese and a metal salt of at least one of cobalt and nickel.

Abstract: A method for producing a mixed metal solution containing manganese ions and at least one of cobalt ions and nickel ions, the method including: an Al removal step of subjecting an acidic solution containing at least manganese ions and aluminum ions, and at least one of cobalt ions and nickel ions, to removal of the aluminum ions by extracting the aluminum ions into a solvent while leaving at least a part of the manganese ions in the acidic solution in an aqueous phase, the acidic solution being obtained by subjecting battery powder of lithium ion batteries to a leaching step; and a metal extraction step of bringing an extracted residual liquid obtained in the Al removal step to an equilibrium pH of 6.5 to 7.5 using a solvent containing a carboxylic acid-based extracting agent, extracting at least one of the manganese ions and at least one of the cobalt ions and the nickel ions into the solvent, and then back-extracting the manganese ions and at least one of the cobalt ions and nickel ions.

Abstract: 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, the method including: 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; and a second extraction step for Co recovery, the second extraction step being for extracting cobalt ions by solvent extraction from a stripped solution obtained in the first extraction step for Co recovery and stripping the cobalt ions, wherein the first extraction step for Co recovery includes: a solvent extraction process for extracting cobalt ions in the acidic solution into a solvent; a scrubbing process for scrubbing the solvent that has extracted the cobalt ions; and a stripping process for stripping the cobalt io

Abstract: 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 dis