| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for electrolytically oxidizing a waste liquid of an etching solution containing iron chloride or copper chloride effectively from a viewpoint of a capital cost and an operation cost, while inhibiting the waste liquid of the etching solution from excessively being oxidized on an anode surface and preventing chlorine gas from being evolved from an electrolytic tank, in a process of electrolytically oxidizing a lower valence ion in the waste liquid into a higher valence ion by passing the waste liquid in the electrolytic tank as an electrolytic solution. SOLUTION: In the process of electrolytically oxidizing the lower valence ion in the waste liquid of the etching solution containing iron chloride into the higher valence ion by passing the waste liquid as an electrolytic solution into the electrolytic tank formed of an anode chamber and a cathode chamber which are separated by a diaphragm, this oxidization method includes supplying the waste liquid to a particular electrolytic tank, and controlling a control value for the oxidation-reduction potential of a discharged liquid from the anode chamber to 550 to 800 mV (based on silver/silver chloride electrode), while circulating 15 to 50% of the quantity of the discharged liquid from the anode chamber as a supply solution. COPYRIGHT: (C)2009,JPO&INPIT
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