An: 30 N: 35
Who: Andreas Marggraf
German: zin (German for tin). “Zinc” in different languages.
Found in the minerals zinc blende (sphalerite) (ZnS), calamine (ZnO), franklinite ((Fe,Mn,Zn)(Fe,Mn)2O4), smithsonite (ZnCO3), willemite (Zn2SiO4), and zincite (ZnO). The largest producers are Australia, Canada, Peru and the USA. Annual production is around 5 million tons.
Universe: 0.3 ppm (by weight)
Used to coat other metals (galvanizing) to protect them from rusting. Used in alloys such as brass, bronze, nickel. Also in solder, cosmetics and pigments.
In ancient India the production of zinc metal was very common. Many mine sites of Zawarmaala were active even during 1300-1000 BC. There are references of medicinal uses of zinc in the Charaka Samhita (300 BC). The Rasaratna Samuccaya (800 AD) explains the existence of two types of ores for zinc metal, one of which is ideal for metal extraction while the other is used for medicinal purpose. Zinc alloys have been used for centuries, as brass goods dating to 1000-1400 BC have been found in Israel and zinc objects with 87% zinc have been found in prehistoric Transylvania. Because of the low boiling point and high chemical reactivity of this metal (isolated zinc would tend to go up the chimney rather than be captured), the true nature of this metal was not understood in ancient times.
The earth has been estimated to have 46 years supply of zinc. A chemist estimated in 2007 that at the current rate of usage, the world’s supply of zinc would be exhausted by about the year 2037.
Zinc powder is very flammable. Zinc may be harmful if swallowed or inhaled, and may act as an irritant.
Reactions of Zinc
Occurrence and Production of Zinc
There are zinc mines throughout the world, with the largest producers being China, Australia and Peru. In 2005, China produced almost one-fourth of the global zinc output, reports the British Geological Survey. Mines and refineries in Europe include Umicore in Belgium, Tara, Galmoy and Lisheen in Ireland, and Zinkgruvan in Sweden. Zinc metal is produced using extractive metallurgy. Zinc sulfide (sphalerite) minerals are concentrated using the froth flotation method and then usually roasted using pyrometallurgy to oxidise the zinc sulfide to zinc oxide. The zinc oxide is leached in several stages of increasingly stronger sulfuric acid (H2SO4). Iron is usually rejected as Jarosite or goethite, removing other impurities at the same time. The final purification uses zinc dust to remove copper, cadmium and cobalt. The metal is then extracted from the solution by electrowinning as cathodic deposits. Zinc cathodes can be directly cast or alloyed with aluminium.