METHOD AND DEVICE FOR TREATING IODINE-CONTAINING ETCHING SOLUTION WHICH CONTAINS Au

The purpose of the present invention is to establish a technique which enables the collection of Au from a used iodine-containing etching solution with a high collection rate and also enables the restoring of the concentration of iodine (I 3 - ) in the etching solution to recover the etching ability of the etching solution. A method for treating a iodine-containing etching solution that contains Au, which comprises electrolyzing the etching solution to collect Au from the etching solution and restore the concentration of iodine (I 3 - ), wherein the electrolysis is carried out while keeping the cathode potential at -0.7 V or more (wherein the reference potential is a potential of a reference electrode Ag/AgCl) and the anode potential at +1.0 V or less (wherein the reference potential is a potential of a reference electrode Ag/AgCl).