Zinc

(German Zink, of obscure origin) Centuries before zinc was recognized as a distinctelement, zinc ores were used for making brass. Tubal-Cain, seven generations from Adam, ismentioned as being an "instructor in every artificer in brass and iron." Analloy containing 87 percent zinc has been found in prehistoric ruins in Transylvania.

Metallic zinc was produced in the 13th century A.D. in India by reducing calamine withorganic substances such as wool. The metal was rediscovered in Europe by Marggraf in 1746,who showed that it could be obtained by reducing calamine with charcoal.

The principal ores of zinc are sphalerite (sulfide), smithsonite (carbonate), calamine(silicate), and franklinite (zine, manganese, iron oxide). One method of zinc extractioninvolves roasting its ores to form the oxide and reducing the oxide with coal or carbon,with subsequent distillation of the metal.