| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for treating an etching waste soln. capable of producing an etching soln. capable of increasing etching efficiency in such a manner that working quality in etching treatment is satisfactorily maintained. SOLUTION: This method has a 1st stage in which a part of an etching waste soln. exhausted from an etching factory 11 is fed respectively to a cathode side and an anode side in an electrolyzing cell 20, and a refined soln. obtd. by oxidizing ferrous ions into ferric ions is taken out and a 2nd stage in which the refined soln. obtd. in the 1st stage is mixed with a supplementary soln. and/or the balance of the etching waste soln. largely contg. ferric ions, and ferrous ions contained by the blowing of gaseous chlorine are oxidized into ferric ions, the quantity of the etching waste soln. and supplementary soln. in the 2nd stage to be poured is controlled to control the concn. of nonferrous metallic ions in the obtd. etching soln., by which it is formed into the etching soln. with a reaction rate corresponding to the object to be etched.
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