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.

Abstract: An electrolytic apparatus and process for the on-line regeneration of acid cupric chloride etching baths used in printed circuit board fabrication is described. The apparatus utilizes a regeneration process which exactly reverses the reaction Cu+CuCl.sub.2 .fwdarw.2CuCl in order that the copper metal etched into the system is completely removed while at the same time maintaining the concentration of cuprous and cupric chloride within the desired range. A preferred system utilizes a flow-through graphite or carbon anode and a flow-by cathode, allowing for more precise control of current/potential variables. The cell utilizes low operating voltage resulting in less waste heat generation and lower electrical costs and improved on-line process control, leading to improved operating efficiencies and reliability in terms of unscheduled maintenance and outages.

Abstract: A process and apparatus for producing surface treated metal foil is described. The process comprises plating a relatively smooth metal foil onto a cathodic surface and thereafter forming a dendritic layer on the foil and firmly bonding it thereto while the foil is still on the cathodic surface. In one embodiment, the apparatus comprises an electrolytic cell containing an electrolyte, a rotating drum cathode at least partially immersed in the electrolyte, at least two primary anodes and a plurality of treatment anodes embedded in one of the primary anodes.