Symbol:Zn
Melting point: 419.5'C
Electron configuration:[Ar]3d104s2
Atomic number:30
Atomic mass:65.38+0.002 u
OreCommon NameFormula
Oxide ZinciteZnO
OxideFranklinite(Fe,Zn,Mn)(Fe,Mn)2O4
SulphideZinc blende/SphaleriteZnS
CarbonateSmithsonite/CalamineZnCO3
CarbonateHydrozinciteZn5(OH)6(CO3)2
SulphateGoslariteZnSO4.7H2O
SilicateWillemiteZn2SiO4
SilicateHemimorphiteZnSi2O7(OH)2.H2O

Zinc

Zinc is bluish white metal with melting point of 419'C. It is fairly heavy and show high resistance to corrosion. It has good alloying properties. The protection of iron and steel from corrosion is carried out with zinc coating. The method of applying zinc coating on the iron and steel is known as galvanizing. Zinc coating is also provided to other metal containers. It has good casting properties. Zinc is used for producing alloys like brass, German silver and white metal. It is used in tubes of toothpastes. Zinc oxide and Zinc sulphide are used in pigments and paints. Zinc oxide is used in rubber industry as an accelerator in vulcanizing process. Zinc salts are used in producing glues, dyes and wood preservatives. The important zinc ore is Sphalerite/zinc blende. It is a sulphide of zinc. It is found in association with lead minerals galena. Other important zinc minerals are Zincaite, Franklinite, Smithsonite and Willemite. The zinc mineral producing countries are Canada, Australia, Peru, U.S.A, Mexico, Russia, India and South Africa. The important producers of zinc metal are U.S.A, Russia, Germany, Japan, Sweden, Canada, South Africa, India, Yugoslavia, Poland and Hungary.

Application of Zinc as a coating material: Application of zinc as a coating material on the surface of iron and steel to check corrosion is in practice for long time. Zinc is anodic to iron and protects iron when it is not closer to the properties of zinc. Coating of zinc is applied on the surface of metals through processes like galvanizing, sherardizing, spraying, painting and electroplating. In case of galvanizing, the clean surface of steel is coated by immersion in a bath of molten zinc. In case of sherardizing, zinc is converted into powder and heated with steel. Heating is carried out between 250'C-450'C. In case of spraying molten zinc metal is spread on the surface of the steel. Painting of metal surface is carried out by applying zinc based paints. Electroplating is done by electrolysis of zinc sulphate solution. The wires, sheets or pipes are used as cathodes and aluminium strips are used as anodes. Zinc is produced from the zinc sulphate solution during the electrolysis and deposited on the cathode points. In this way, the metals are coated with zinc through electroplating method.

Alloys of Zinc

Brass is the most important alloy of copper and zinc. The brass containing up to 30% of zinc is called alpha-brass. This alloy has good corrosion resistance. The color of the alloy is reddish when the zinc content up to 20%. The color becomes yellow as the zinc content increases up to 36%. The zinc content between 36%-46% makes the alloy more corrosion resistance. It is known as alpha-beta brass. When the zinc is more than 46.6%, the alloy is called beta brass. If the zinc is more than 60%, it may be called gamma-brass. Brass is used for coin, medal, plaque, cap, jewelry, drivet, screws, electrical sockets, bullet covers, plumbing pipes and corrosion resistance tube. Addition of tin improves resistance to corrosion. Addition of aluminium also increases strength and corrosion resistance. These alloys are used in steam-boiler plants as heat exchange tubes. These alloys are also used in springs, fasteners and plumbing accessories. Some alloys are used in thermostat bellows and musical instruments. Radiator cores, headlight reflectors and flash light shells are produced from brass alloys.

Bronze is also an alloy of copper, zinc and tin. Zinc is added up to 10% in such alloys. It is very hard and shining in appearance. Bronze is used in coins, utensils, medals, ornaments and statues. German silver is an alloy of copper, zinc and nickel. In German silver, copper is present up to 50%. Zinc is added from 25-35%. German silver is white in color and ductile in nature. It is hard and resistant to corrosion. German silver also shows good mechanical properties. German silver is used for making of electrical parts, utensils, ornaments and decorative items. Gun metal is an alloy of copper, tin and zinc. Zinc is added up to 2%. It is added to remove the impurities and increase the fluidity of the alloys. Gun metal is used in production of rifle barrels, bearings and gears. Another alloy of zinc is Muntz metal. Muntz metal is an alloy of copper, zinc and lead. Zinc is present up to 40%. It is used for small components of machines, electrical equipments, fuses, rods, rivets, screws, tubes and ordinance equipments.