Abstract
Large amounts of spent electroless nickel plating baths are being treated by the conventional precipitation method. The stringency of the landfill space and big loss of nickel have given the researchers an urgent task to develop a less sludge generation and effective nickel recycling technique. High recovery efficiencies of nickel from the model spent baths by solvent extraction using a mixer-settler extractor were reported by us. It was found that the extraction efficiency was affected by the operation parameters such as the flow rates of aqueous and organic phases and the number of extraction stages. In this study, these effects were quantitatively studied on the basis of the extraction rate equation considering the hydrodynamics in the mixer. Then an engineering model was established for simulating the extraction efficiency of nickel during a multistage operation.
