Zinc

Zinc is an elemental metal. It is listed on the Periodic Table as "Zn," with an atomic number of 30 and an atomic weight of 65.37, and it melts at 788°F (420°C). Zinc is usually a gray metallic color, but it can be polished to a shiny silver luster. In nature, it is only found as a chemical compound, not as pure zinc, and can be used as a raw material for castings and coatings.

During the era of the Roman Empire, people used zinc to alloy copper into brass for weapons. In this crude process, the zinc was captured by the copper during the heating of the ores, though little was realized at the time about the importance of zinc in metallurgy. The name zinc may be derived from the German word "zinn," which means tin. The scientific discovery of zinc is credited to Nadreas Sigismund Marggraf, a German chemist who isolated pure zinc in 1746. The first production facility, or smelter, was founded in Bristol, England by William Champion shortly thereafter.

Only about 5% of the world's zinc supply is mined in the United States, with the balance coming primarily from India, Mexico, and Canada. Approximately 6.7 million metric tons of zinc ore are produced worldwide. Roughly two thirds of the zinc used in the United States is imported.

Zinc

Zinc Uses

Zinc is primarily used for galvanizing steel against corrosion, die casting of intricate machine parts, and in batteries and other electrical applications. Zinc is also alloyed with copper to form brass.

Galvanizing steel involves applying a thin coating of zinc to all exposed surfaces of the steel to guard against corrosion. Zinc offers excellent corrosion resistance because it is more easily oxidized by the atmosphere. Oxidation occurs when metal is exposed to air or water, and electrons from the metal transfer to the oxygen. When zinc is tightly bonded to steel, the zinc frees up its electrons more readily than the steel, leaving the stronger metal beneath intact. The application of the zinc coating is accomplished by dipping the steel into molten zinc or by electrolytic plating of the steel with zinc, much like chrome plating.

  • The most important use is for alloying with copper in making brass or composition
  • useful for galvanizing iron to protect against rusting.
  • Zinc plates are used extensively in electric batteries.

Because of the strength to weight ratio of zinc, its use by the automotive industry as a die casting has been diminishing in the past few years. Magnesium, aluminum, and plastics have taken over many zinc applications. The use of zinc to galvanize automobile body parts has been increasing, however. Many vehicles today are protected by zinc galvanizing which allows the manufacturer to offer extended warranties for body rust problems with new cars.