In the 1200’s, India produced zinc metal by burning organic materials with smithsonite (ZnCO3, zinc carbonate). Zinc was used long before it was known to be a distinct element. Brass items (brass is an alloy, that is, a mixture, of copper and zinc) have been discovered dating back to as early as 1000 B.C. Zinc was isolated and identified as a distinct element in 1746 by the German, Andreas Marggraf.
Zinc is a blue-gray, metallic element, with the atomic number 30. At room temperature, zinc is brittle, but it becomes malleable at 100 C. Zinc is a moderately good conductor of electricity and is relatively resistant to corrosion in air or water, and therefore is used as a protective layer on iron products to protect them from rusting.
Zinc is recovered from a number of different zinc minerals including sphalerite (ZnS), smithsonite (ZnCO3), and zincite (ZnO).
Adequate amounts of zinc are essential to a healthy life in all humans and animals. It is necessary for the function of a number of different enzymes. It has also been proved necessary for skin and bone growth as well as sexual maturation. The body uses zinc to process food and nutrients. When animals do not have enough zinc in their systems, they need to consume 50% more food to match the weight gain of an animal with enough zinc in its body. About 0.003% zinc is needed for proper health.
Major zinc producing nations include the United States, Canada, Australia, Mexico and Peru.
Zinc is relatively non-reactive in air or water. Consequently, it is applied in thin layers to iron and steel products that need to be protected from rusting. This process is called galvanizing in which the metal is dipped in molten zinc. More than half of the zinc consumed is used for galvanizing.
The second largest use of zinc is as an alloy and the remaining zinc consumption is for making paint, chemicals, agricultural applications, in the rubber industry, in TV screens, fluorescent lights and for dry cell batteries.
There are a number of alternative materials that are used in place of zinc. For example, aluminum and plastics can be used in place of galvanized steel. A number of elements can replace zinc in its electronics and paint applications. Cadmium and aluminum alloy coatings can be used in place of zinc to protect steel from corrosion.