Picture of Sample of Zirconium: (click to see alternate picture)
Atomic Number: 40
Atomic Mass: 91.224
Naturally occurring zirconium contains five isotopes. Fifteen
other isotopes are known to exist. Zircon, ZrSiO4, the principal ore,
is pure ZrO2 in crystalline form having a hafnium content of about
Zirconium also occurs in some 30 other recognized mineral species. Zirconium is produced commercially by reduction of chloride with magnesium (the Kroll Process), and by other methods. It is a grayish-white lustrous metal. When finely divided, the metal may ignite spontaneously in air, especially at elevated temperatures. The solid metal is much more difficult to ignite. The inherent toxicity of zirconium compounds is low.
Hafnium is invariably found in zirconium ores, and the separation is difficult.
Commercial-grade zirconium contains from 1 to 3% hafnium. Zirconium has a low absorption cross section for neutrons, and is therfore used for nuclear energy applications, such as for cladding fuel elements. Commercial nuclear power generation now takes more than 90% of zirconium metal production. Reactors of the commercial size, now being made, may use as much as a half-million linear feet of zirconium alloy tubing.
List of Isotopes, with half lifes:
81Zr 15 seconds
82Zr 32 seconds
83Zr 44 seconds
84Zr 25.9 minutes
85Zr 7.86 minutes
85m1Zr 10.9 seconds
86Zr 16.5 hours
87Zr 1.68 hours
87m1Zr 14.0 seconds
88Zr 83.4 days
89Zr 78.41 hours
89m1Zr 4.18 minutes
90Zr stable %Abundance = 51.45
90m1Zr 809.2 milliseconds
91Zr stable %Abundance = 11.22
92Zr stable %Abundance = 17.15
93Zr 1.53 X 106 years
94Zr stable %Abundance = 17.38
95Zr 64.02 days
96Zr 3.8 X 1019 years %Abundance = 2.80
97Zr 16.91 hours
98Zr 30.7 seconds
99Zr 2.1 seconds
100Zr 7.1 seconds
101Zr 2.3 seconds
102Zr 2.9 seconds
103Zr 1.3 seconds
104Zr 1.2 seconds
105Zr 0.6 seconds
Ground state electronic configuration:
Common oxidation states: I, II, III, IV
Physical appearance (color, state, etc.)
Color: silvery white
Standard State: solid at 298K
Physical properties (melting point, boiling point, crystal structure, density)
Melting Point: 2128 K
Boiling Point: 4628 K
Density: 6511 kg m-3
Crystal Structure: (click on picture to see alternate crystal structure view)
Electronegativity: Pauling Electronegativity: 1.33 Pauling Units
Zirconium is found in abundance in S-type stars, and has been identified in the sun and meteorites. Analysis of lunar rock samples obtained during the various Apollo missions to the moon show a surprisingly high zirconium oxide content, compared with terrestrial rocks
Zirconium is also available from commercial sources so preparation in the laboratory is not normally required. In industry, reduction of ores with carbon is not a useful option as intractable carbides are produced. As for titanium, the Kroll method is used for zirconium and involves the action of chlorine and carbon upon baddeleyite (ZrO2). The resultant titanium tetrachloride, ZrCl4, is separated from the iron trichloride, FeCl3, by fractional distillation. Finally ZrCl4 is reduced to metallic zirconium by reduction with magnesium, Mg. Air is excluded so as to prevent contamination of the product with oxygen or nitrogen.
ZrO2 + 2Cl2 + 2C (900°C) ZrCl4 + 2CO
ZrCl4 + 2Mg (1100°C) 2MgCl2 + Zr
Excess magnesium and magnesium dichloride is removed from the product by treatment with water and hydrochloric acid to leave a zirconium "sponge". This can be melted under helium by electrical heating.
Price per kilogram:
Zirconium of about 99.6% purity is available at a cost of about $150/kg.
The metal is used in the nuclear industry for cladding fuel elements since it has a low absorption cross section for neutrons. Zirconium is very resistant to corrosion by many common acids and alkalis and by sea water. It is therefore used extensively by the chemical industry where corrosive agents are employed. The metal is used as an alloying agent in steel and for making surgical appliances. The metal super conducts at low temperatures and zirconium/niobium alloys are used to make superconductor magnets. Alloys with zinc become magnetic at temperatures below 35 K. Zirconium is used as a "getter" in vacuum tubes, in flash bulbs for photography, in explosive primers, and in lamp filaments.
The oxide (zircon) has a high index of refraction and is a good gem material. The oxide is also used for laboratory crucibles that will withstand heat shock, for linings of metallurgical furnaces, and by the glass and ceramic industries as a refractory material.
The use of zirconium oxides in
technical ceramics is well established, notably for their electrical, wear and
heat resistant properties. A huge range of commercial and domestic products
now incorporate zirconia as a vital ingredient.
For example, our electronic grade materials are used in capacitors, microwave telecommunication systems and piezoelectric applications where the high reactivity and particle size are carefully controlled to maximise zirconate formation.
Other applications for these versatile materials include zirconia gemstones, wear part ceramics, filters for molten metal and fiber optic connectors.
|APPLICATION||USES AND BENEFITS|
||Promotes greater printing ink adhesion to plastics and metals.|
|ALLOYS||Gives added strength to lightweight alloys.|
||Antiperspirant component in 'roll-on' deodorants.|
||Silica free foundry binders.|
|CATALYSIS||Catalytic systems for the control and support of general catalysis.|
||Enhanced cement fluidity while pumping.|
colours and glazes
of low toxicity.
||Wool flameproofing and waterproofing emulsions.|
||Used in printing inks and polymers.|
|DRILLING MUDS||Clay stabilisers for improvement of drilling muds in the oil industry.|
||Dielectrics for use in capacitors, sensors and piezoelectrics.|
||Tough wear-resistant technical ceramics.|
||Zirconia gemstones in most high street jewellers.|
||For glass toughening and optical property control.|
|ION EXCHANGE||For use in kidney dialysis and removal of toxic impurities in water.|
||For improved paint film adhesion.|
||Strength giving, water resistant surface coatings for paper and paperboard.|
||For better weathering of paint films.|
||Various additives including crosslinkers.|
||To improve aircraft fuel consumption.|
The name zircon probably originated from the arabic "zargun", which describes the color of the gemstone now known as zircon (ZrSiO4). The minerals jargon, hyacinth, and jacinth also contain zircon and these have been known since biblical times and are mentioned in the bible in several places. The existence of a new element within these minerals was not suspected until studies by Martin Heinrich Klaproth in the late 18th century. Although used and worn as gemstones back in biblical times, it was not until 1789 that zirconia was discovered and named. Martin Heinrich Klaproth, a German chemist, made the discovery when he heated a gemstone with alkali. From the product of that reaction he extracted an oxide of a new element which he called zirconia from the Arabic "zargon" meaning gold-colored.
In 1824 Swedish chemist, Jons Jacob
Berzelius, isolated the metal, by mixing potassium and potassium zirconium
fluoride together in an iron tube, but it was not until the 1950's that useful
applications for zirconium were found.
In that decade Magnesium Elektron Limited (MEL) became the first company to exploit zirconium commercially when they introduced their oxides for ceramic colours. Research undertaken at MEL's Clifton Junction laboratories, soon discovered a wide range of other uses for zirconium.
Phosphates, suitable for human kidney
dialysis were quickly followed by many novel products ideal for use across a
huge spectrum of manufacturing processes. Recent developments have focused on
catalysis, where formed zirconia shapes are beginning to impact on advanced
Zirconium compounds are generally regarded to be of low toxicity when compared to their alternatives. The vast majority are classified as being non-hazardous to the ecosphere, a very valuable benefit in the light of environmental issues. Some of our products are approved for use in contact with food.
Pictures of Various Uses of Zirconium:
MEL Chemicals: Zirconium Chemistry
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