BRIGHT ZINC PLATING.

Improvements in zinc plating have largely been made possible by improvement in zinc brighteners in conventional cyanide systems, but advances have also been made in noncyanide systems. Zinc plating is now commercially deposited both from the well proven cyanide baths and also from low cyanide, noncyanide alkaline (zincate), acid sulfate, acid chloride and neutral chloride solutions. These various types are discussed with emphasis on their particular features, applications, and limitations. Practical control procedures are explained with particular reference to the effects and removal of common contaminants. The effectiveness of recognized purification procedures such as zinc dust treatments are studied with different types of additive systems in alkaline baths. The important environmental matters relating to treatment of effluents are discussed for the various types of zinc solutions. Influence of types of formulation and types of additives on the effectiveness of removal of zinc from effluent are discussed.