Determination of the optimum conditions for the cementation of cadmium with zinc powder in sulfate medium

The orthogonal array design has been used to determine the optimum conditions for the cementation of cadmium from a synthetic zinc sulfate solution and hence to achieve the highest cementation efficiency and the best robustness of the quantitation from the least number of trials in a laboratory scale. Cementation was performed using zinc powder. The orthogonal array L9 (34) that comprises four parameters at three levels was chosen. The parameters and their levels were as: zinc powder quantity (Z): 1, 1.2 and 1.5 times of stoichiometric quantity of cadmium; time (t): 4, 8 and 12 min; temperature (T): 25, 35 and 45 °C and zinc powder particle size distribution (R): nos. 1–3. The ultimate optimum cementation conditions were found to be Z1 (equal to stoichiometric quantity of cadmium), T1 (25 °C), R3 (no. 3) and t1 (4 min). Under these conditions, cementation percentages for cadmium and nickel were 95.83% and 6.63%, respectively.