Abstract: The present invention relates to an apparatus and a process for regenerating a used etchant solution, which solution contains a metal in divalent form. The apparatus includes a tank which is originally supplied with the etchant solution; a first electrolytic cell for converting solution from the tank to a solution containing a high fraction of a monovalent form of the metal; and a second electrolytic tank for plating metal from the solution containing a high fraction of the monovalent form of the metal. The details of the process of the present invention are set forth in the disclosure.