VALUABLE METAL RECOVERY METHOD

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; 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; and an extraction step for Ni recovery, the extraction step being for extracting nickel ions by solvent extraction from an extracted residual solution obtained in the first extraction step for Co recovery and stripping the nickel 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 ions in the solvent after the scrubbing into a solution.