Method for regenerating plating liquid, plating method, and plating apparatus

A method for plating a steel wire with plating liquid containing Cu ions, the method comprising:

• performing electrolytic degreasing on the surface of the wire by applying electric current with the wire immersed in degreasing liquid, to obtain a pretreated wire;
• plating the pretreated wire by immersing the wire in a plating liquid comprising Cu ions to obtain a plated wire;
• washing the surface of the plated wire by immersing the plated wire in cleaning liquid comprising water as a major constituent;
• and
• drying the washed wire;
• wherein the plating liquid is regenerated by a method comprising (i), (ii), (iii) and (iv):
• (i) applying electric current between a plating waste liquid side taken as a cathode and an electrolytic solution side taken as an anode, such that the plating waste liquid and the electrolytic solution are connected through an anion exchanger, wherein the plating waste liquid comprises Fe ions and Cu ions;
• (ii) separating copper from the plating waste liquid by making a copper deposition electrode as a result of depositing copper on an electrode in contact with the plating waste liquid, to convert the plating waste liquid to a processed remaining liquid, wherein an anode in contact with the electrolytic solution is a copper deposition electrode formed previously;
• (iii) dissolving copper in the electrolytic solution to generate a copper ion-containing solution;
• and
• (iv) repeating (i), (ii) and (iii) one or more times;
• wherein the regeneration is performed while plating waste liquid produced from the plating liquid during the plating is made to contact the cathode, and waste liquid from the washing is made to contact the anode;
• the processed remaining liquid is added to the degreasing liquid for the degreasing, and the copper ion-containing solution is added to the plating liquid for the plating;
• Fe ions are removed from the degreasing liquid, to reduce an Fe ion concentration;
• and
• an amount of water added to the cleaning liquid during the washing is approximately equal to an amount of water vaporizing during the electrolytic degreasing.