16. Zinc and Zinc Alloys

This chapter presents key facts about zinc's role in the world together with technical reasons for its widespread use. The frequency and occurrence of zinc resources are compared with present and forecast demand, showing that more than 200 years of future demand will be met by known zinc resources. An overview of the primary zinc production process is then given, including an overview of the mining, aqueous concentration, roasting, cementation and electrolytic refining steps. Mechanical, thermal and crystallographic properties of zinc are then provided, especially for the most widely produced and used grade, 99.99% (special high grade) zinc. The principal uses of zinc and its alloys are then described. The most important use of zinc is the corrosion protection of steel; the usual reactions occurring during corrosion of galvanized steel are given together with corrosion rates typical of many environments where it is used. The next most important use is zinc die casting alloys; the composition of these alloys and their engineering properties are provided. Compositions and technical characteristics of other applications including rolled and thermal sprayed zinc, as well as zinc anodes, are also given.