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Zirconium

 

 

ZirconiumThe demand for Zirconium in the nuclear industry is the main driver for the production of Zirconium in metal form. Out of the 1.3 million tonnes of Zirconia mined each year, less than 1% ends up as Zr metal. 

The majority of Zirconium is used in fuel assemblies in nuclear reactors, due to its low neutron-capture cross-section.

For this reason the main global producers of Zirconium have historically been the nuclear powers – USA, Russia, France.

Zirconium

What has changed in the last two decades has been the evolution and proliferation of Zirconium in non-nuclear applications. Examples of these are in electronics, amorphous alloys, and in other more basic master alloys (AlZr, FeZr, CuZr) where Zr adds strength to final products. The Zr for alloy uses is usually supplied via the off-cuts/production scrap generated during manufacture of semi-finish Zirconium products (tube, sheet, assemblies).

It is thought that world production of Zr is about 6,000 mtpy with capacity in France of about 2,600 mt, balance in USA, Ukraine, Russia. China is emerging as a producer but is not yet widely approved in nuclear applications.

Zirconium FACTS

It was discovered in 1789 by M.H. Klaproth at the University of Berlin and was isolated in 1824 by J.J. Berzelius in Stockholm.

It has a hard lustrous silvery metal, which is very resistant towards corrosion as its surface is covered by an oxide layer. It is unaffected by acids (except those containing Hf) and alkalis. When it is in its fine form (swarf) it can ignite in air.

ZirconiumIt is found in Zircon(ZrSiO4) and baddeleyite(ZnO2). Extraction is by chlorination to give ZrCl4. Although it is treated as a rare metal, it is in fact the twelfth most common element in order of abundance, the scarcity being solely caused by extreme difficulty in extraction.

It is used in alloys, coloured glazes and nuclear reactors where it has low neutron absorption properties. Its oxides are used in foundry crucibles, refractory bricks, ceramics and abrasives.

Most of its compounds are complexes of Zr(IV). Zr(IV) oxide (Zirconia) is used as an electrolyte in fuel cells. The metal is also used as electric lamp filaments when the power required per candle power produced is lower than with the tungsten filament lamps.

Atomic no.
Relative atomic mass
Melting point
Boiling point
Density
Electrical resistivity
Young’s modulus
Heat capacity
Abundance
Thermal conductivity
40
91.224
1855 °C
4409°C
6506kgm-3
42.1 nΩm
68 Gpa
25.36 J/K/mol
190 ppm
22.6 W /m/K