To provide a treatment method for an electroless plating liquid, which removes undesired components accumulating in the electroless plating liquid and recycles useful components.
The treatment method for the electroless nickel-plating liquid comprises the following steps: (i) a step of obtaining a concentrated liquid of a phosphite by primarily electrodialyzing the plating liquid containing a hypophosphite as a reducing agent, in a demineralization chamber of a primary electrodialysis tank provided with a cation exchange membrane and an anion exchange membrane, (ii) when a concentration of a metal nickel in the concentrated liquid provided in the above step (i) is 1.5 g/l or higher, a step of obtaining a concentrated liquid containing a metal nickel with a concentration of less than 1.5 g/l, by electrodialyzing the previous concentrated liquid in a demineralization chamber of a supplementary electrodialysis tank provided with the cation exchange membrane and the anion exchange membrane, and (iii) a step of adjusting the concentrated liquid containing the metal nickel with a concentration of less than 1.5 g/l, which has been provided in the above steps (i) or (ii), to pH 6 to 10, and then secondarily electrodialyzing the liquid to separate it into a demineralized liquid and a concentrated liquid in a demineralization chamber of a secondary electrodialysis tank provided with a monovalence selective cation-exchange membrane and a monovalence selective anion-exchange membrane.
COPYRIGHT: (C)2004,JPO
Makino Katsuko
Takashi Yokohata
Moto Okumura
Tokuda Yuji
Yutaka Nakagishi
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Kakehi Yuro
Takeshi Ohara
Hiroji Nakagawa
Yasumitsu Tate
Kenji Saito
Jun Fujii
Hitoshi Seki
Mutsuko Nakano