METHOD FOR REPRODUCING VALUABLE METAL

The present invention provides a novel method that makes it possible to efficiently separate Cu from battery waste containing Ni, Co, and Cu. A method for reproducing valuable metals according to the present disclosure includes: a step of roasting waste of a lithium ion secondary battery to obtain a roasted product; and a step of leaching Cu from the roasted product using an ammonia water. The waste contains Ni, Co, and Cu. The roasting is performed such that the roasted product contains Ni and Co in an oxide form and Cu in a metal form.