Nickel recovery from the rinse waters of plating baths

An electrolytic process is applied to the de-metalization of rinse waters emerging from nickel-plating baths. Optimum conditions of nickel recovery from this type of solution have been investigated through a series of experiments carried out in a rotating packed cell (Rollschichtzelle®). The effects of temperature and pH of electrolyte, current density, cell rotation speed, and diameter of the cathode granules were examined. Ninety percent of the nickel was recovered from a solution of 450 mL volume, with a pH of 5.5±0.05, 2 g/L initial nickel concentration, and by using cathode granules of 5 mm in diameter. At 50 °C electrolyte temperature and 325 A/m2 current density, 74% current efficiency was attained with 4.2 kWh/kg Ni energy consumption.