METHOD FOR REPRODUCING VALUABLE METAL

The present invention provides a novel method capable of recovering Ni and Co as well as Cu from a battery waste containing Ni, Co, and Cu with a high recovery ratio, in which a leaching agent is suitable for reuse. The method for reproducing valuable metals according to the present disclosure includes: a Cu leaching step of leaching Cu, using an ammonia water, from battery waste containing Ni, Co, and Cu into the ammonia water; and an Ni and Co leaching step of leaching Ni and Co, using an ammonia aqueous solution containing ammonia and at least one inorganic ammonium salt selected from a group consisting of ammonium sulfate and ammonium carbonate, from a solid residue obtained in the Cu leaching step into the ammonia aqueous solution.