Metallic nickel is recovered from wastes, e.g. electroplating sludge, by dissolution as sulfate, precipitation as hydroxide, calcination to oxide and reduction with hydrogen

摘要

Metallic nickel recovery from wastes comprises dissolution as the sulfate, precipitation as the hydroxide, calcination to the oxide and reduction with hydrogen, is new. Metallic nickel is recovered from electroplating sludges or other wastes containing nickel and other non-ferrous metal(s) by dissolving the nickel as the sulfate, precipitating any other dissolved non-ferrous metal sulfate(s) and adding an alkali to precipitate nickel hydroxide which is then calcined to nickel oxide and reduced with hydrogen to metallic nickel.