METHOD FOR RECOVERING AND RECYCLING PALLADIUM OR PALLADIUM ALLOY FROM CONTACT MATERIAL

摘要

PURPOSE:To recover high-grade palladium capable of being recycled as such at a low cost in a short time by treating a contact material electrolytically or with an acidic soln. to dissolve and separate the base material and then treating the obtained palladium with acid. CONSTITUTION:Noble metals are recovered from the scraps of the contact material obtained by welding palladium or palladium alloy to the base material of copper or copper alloy. The contact material is electrolyzed as an anode and/or treated with hot concd. sulfuric acid or sulfuric acid-hydrogen peroxide mixed soln. to dissolve and separate the base material. The palladium or palladium alloy as an anode slime is treated with acid to dissolve off the surface part rich in impurities such as the diffused layer of the base material. The acid treatment is conducted with a hydrochloric acid-hydrogen peroxide mixed soln., nitric acid, aqua regia or nitric acid-hydrogen peroxide mixed soln., and about 1-5wt.% of palladium is appropriately dissolved in this case.