| CPC C22B 23/0461 (2013.01) [C22B 7/007 (2013.01); C22B 23/0484 (2013.01); H01M 10/54 (2013.01); C22B 26/12 (2013.01); Y02W 30/84 (2015.05)] | 9 Claims | 

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               1. A method for recovering a valuable metal, the method 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 comprising: 
            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 comprises: 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, and 
                wherein a phosphonate ester-based extracting agent is used as a first extracting agent in the first extraction step, and an extracting agent different from the first extracting agent is used as a second extracting agent in the second extraction step. 
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