Factors affecting zinc solubility in electroplating waste

Diluted plating solutions collected from electroplating shops were subjected to bench-scale chemical destruction and alkaline precipitation, and zinc solubility in treated wastes was measured from pH 8 to 12. 5 for initial zinc concentrations of 50, 200, 500, and 1000 mg/1. Zinc solubility in treated zinc cyanide plating solutions increased as the initial zinc concentration was increased, and was somewhat higher than in comparable laboratory-prepared zinc-chloride solutions. Addition of other plating solutions increased zinc solubility.