The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 12, 1999
Filed:
Oct. 22, 1997
Fumio Hine, I Karuga Nara, JP;
Fujio Matsui, Hirakata, JP;
C. Uyemura & Co., Ltd., Osaka, JP;
Abstract
Disclosed is a method of treating an electroless nickel plating bath mainly containing a water-soluble nickel salt, a complexing agent for complexing the nickel salt, and sodium hypophosphite as a reducing agent for reducing the nickel salt, including the steps of:repeatedly regenerating and reusing the electroless nickel plating bath in which a phosphite is accumulated by adding nickel sulfate to the plating bath to produce and precipitate nickel phosphite and separating the nickel phosphite from the plating bath; and adding sulfuric acid or a mixture of sulfuric acid and sodium sulfate to the nickel phosphite separated from the plating bath to convert the nickel phosphite into nickel sulfate and phosphorous acid or NaH.sub.2 PO.sub.3, and recovering the nickel sulfate. According to this method, it is possible to simply, positively and inexpensively separate phosphite ions, without inclusion of any impurity, from an aged electroless plating bath in which phosphite ions are accumulated in a large amount, and to simply recover nickel sulfate from the nickel phosphite thus separated from the plating bath and effectively use the nickel sulfate as a reactive medium for removing a plating bath component or phosphite ions.