TECHNOLOGY DEVELOPMENT AND PLANT PRACTICE OF THE RECYCLING OF NICKEL FROM SPENT ELECTROLESS NICKEL PLATING BATHS USING SOLVENT EXTRACTION

摘要

Although electroless nickel plating is an important surface finishing technology, the treatment of a large amount of its spent baths should be established from both the environmental and economic viewpoints. The present authors have developed a nickel recycling process from the spent baths using solvent extraction in which (i) the impurities of iron and zinc are initially removed by an acidic organophosphorous reagent, (ii) the nickel is then extracted using a mixture of a hydroxyoxime reagent and a small amount of an acidic organophosphorous reagent, and (iii) the extractead nickel is stripped by sulfuric acid to form nickel sulfate solution to be reused in the replenishment. This process was applied to a plating plant of Japan Kanigen Co., Ltd, in September 2007, as a part of the production line with an 8-m~3 plating tank and is now contributing to the emission reduction from the plant. In this paper, the laboratory-scale experimental results and practical operation data are presented.