Dissolving copper from substrates - by oxidising copper to cuprous ions using cupric ions

摘要

Process for dissolving copper from a substrate by a) oxidising the copper with cupric ions to form cuprous ions, the cupric ions are provided by a regenerative alkaline corrosive soln contg. cupric ions, ammonium hydroxide, a copper complexing agent chosen from an ammonium salt and a chelating agent, the ammonium complexing agent always being present. b) continuously oxidising cuprous to cupric ions. c) determining the copper ion concn. to ascertain when the copper ion concn has reached a previously determined max. d) removing a certain amt. of the alkaline corrosive soln in response to c) to lower the copper ion concn in the range indicated e) adding neutral/alkaline ammoniacal soln comprising ammonium salt/hydroxide and a chelating agent. The ammonium salt always being added. The addn should be sufficient to replace the ammonium slats/hydroxides and the chelating agents removed at d).