Zinc in nature
Most of the zinc contained in the basic igneous rocks are more than 70 of its minerals, among which the most important are calamine, zinc, sphalerite, Willem smithsonite and Franklin.Typically, they are associated with copper and lead minerals in polymetallic ores.
Zinc actively migrated, this process is particularly noticeable in the thermal waters, where he moved with lead.As one of the nutrients zinc is always present in the tissues of animals and plants.It takes part in enzymatic reactions that take place in cells, stabilize macromolecules various biological membranes.
Physical and chemical properties
have zinc hexagonal close-packed lattice.In the cold state the metal brittle, but 100-150 ° C becomes pliable and susceptible to rolling sheet or foil with a thickness of about one hundredth of a millimete
r.At a temperature of 250 ° C Zinc again becomes brittle and can be istolchen powder.
in air at temperatures up to 100 ° C covers a surface film of zinc carbonate and quickly fades.In humid air, metal failure even at ordinary temperature.Strong heating in air or oxygen causes its combustion bluish flame, forming a white smoke of zinc oxide.
mixture of this metal powder with sulfur under heating gives zinc sulfide.Dry bromo, fluoro and chloro and zinc do not react, but in the presence of water vapor could be ignited zinc.When exposed to hydrogen sulfide and ammonia weakly acidic aqueous solutions of zinc salts, it precipitates.Strong mineral acids actively dissolves the metal, especially when heated, resulting in formation of the corresponding salts.
Preparation and use
Zinc is extracted from ores that contain it in the form of sulphide.Using selective flotation of ores enriched give zinc concentrates, which are then fired in a fluid-bed furnaces.Calcined sintered concentrate to give it the gas permeability and grit, after which it was reduced with coal or coke.Then, metal vapor is condensed and poured into molds.
Zinc also obtained by electrolysis - roasted concentrate was treated with sulfuric acid, a sulfate solution obtained is purified from impurities and subjected to electrolysis baths inside lined with lead.
Zinc is used to protect steel from corrosion.With good casting qualities, this metal is used to create a variety of small parts for airplanes and other machines.Alloys of zinc with copper and lead are commonly used in the art.
- HiMiK.ru, Zinc (chem. Element)