In the chemical industry zinc is used in the form of zinc powders and dusts. These are prepared by pulverizing a stream of molten metal in a jet of compressed air or water. The difference between powder and dust is essentially a matter of fineness, dusts being finer. They are used to purify solutions by cementation or to achieve other reductions. Special grades of zinc powders are also used in alkaline batteries as well as in certain button cells. The electrochemical properties of zinc account for its essential role as a negative electrode in dry (or Leclanché) batteries.
Zinc oxide ZnO, the most widely used zinc compound and is used in the vulcanization of rubber, as well as in ceramics, paints, animal feed and pharmaceuticals, and many other products and processes. A special grade of zinc oxide has long been used in photocopiers. The oxide is also used in varistors (that provide protection against over-voltages).
Zinc sulphide ZnS mixed with barium sulphate is used as a white pigment known as lithopone. ZnS is also used as a detector of alpha-rays, which render it luminescent. ZnS and the selenide ZnSe are used in infrared optics. Zinc salts have various applications: zinc chloride in the textile industry, and as a scaling flux in galvanizing; zinc sulphate in agriculture and animal feed; zinc phosphate to passivate steels, etc. Organic salts of zinc are used in paints, and zinc stearate is used in the preparation of plastics as well as in powder metallurgy.
Despite its many essential uses, sometimes zinc is used purely for entertainment. Have you ever wondered how things glow in the dark? All glow-in-the-dark products contain phosphors. A phosphor is a substance that radiates visible light after being energized. To make a glow-in-the-dark object, you want a phosphor that is energized by normal light and that has a very long persistence. Zinc sulfide has these properties and is used to create everything from luminescent watch dials to glow-in-the-dark toys. Zinc’s phosphorescent properties have also made it a key ingredient in X-ray and TV screens, fluorescent lights and light emitting diodes. Fireworks often make use of zinc dust to create bright, shimmering sparks. The zinc metal flakes heat up until they are incandescent and shine brightly or, at a high enough temperature, actually burn. A variety of chemicals can be added to create the brilliant colors, but it is the zinc that sparkles.Download Case Study