Лако-красочные материалы — производство

3.2.1

Cadmium

A naturally occurring but rare element, cadmium occurs as approximately 150 parts per billion of the earth’s crust. Although cadmium sulfide does occur natu­rally as the mineral Greenockite (named after the Scottish coastal town Greenock), no commercially viable deposits of cadmium exist. It is derived primarily as a waste product from the refining of zinc ores and to a lesser degree from the smelt­ing of copper and lead ores. Being more volatile than zinc, cadmium can be dis­tilled from zinc furnaces. It is then concentrated and refined by distillation and electrolysis to a purity of 99.995%, before being sold as rods, balls or ingots.