| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for treating an etching waste liquid by which copper can be efficiently removed from a waste liquid in simple equipment instead of a conventional neutralization aggregation method. SOLUTION: An etching waste liquid containing ammonium persulfate, sulfuric acid and copper as the main components is treated. The waste liquid is preliminarily treated by a specified method and subjected to an electrolytic process to precipitate copper on the cathode. In the electrolytic process, a titanium material plated with a metal selected from the group of platinum group metals is used as an anode 2, a cathode 3 is preferably disposed as tilted by a specified angle to the anode, and the process is carried out while keeping the current density in the range from 1.5 to 5.0 A/dm2 and the liquid temperature at <=34 deg.C.
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