Everything about Zirconium totally explained
Zirconium (/ˌzɝˈkoʊniəm/) is a
chemical element with the symbol
Zr and
atomic number 40. It is a lustrous, gray-white, strong
transition metal that resembles
titanium. Zirconium is used as an alloying agent due to its high resistance to corrosion. It is never found as a native metal, but is instead obtained mainly from the mineral
zircon, which can be purified by
chlorine. Zirconium was first isolated in an impure form in 1824 by
Berzelius.
Zirconium has no known biological role. Zirconium forms both
inorganic and
organic compounds, such as
zirconium dioxide and
zirconocene dibromide, respectively. There are five naturally-occurring
isotopes, three of which are stable. Short-term exposure to zirconium powder causes minor irritation, and inhalation of zirconium compounds can cause skin and lung
granulomas.
Characteristics
Zirconium is a
lustrous, grayish-white, soft,
ductile, and
malleable metal which is solid at room temperature, though it becomes hard and
brittle at lower purities. However, it'll dissolve in
hydrochloric and
sulfuric acid, especially when
fluorine is present. Alloys with zinc become magnetic below 35 K. Zirconium has an
electronegativity of 1.33 on the Pauling scale. Of the elements within
d-block, Zirconium has the fourth lowest electronegativity after
yttrium,
lutetium, and
hafnium.
Applications
Because of Zirconium's excellent resistance to corrosion, it's often used as an alloying agent in materials that are exposed to corrosive agents, such as surgical appliances, explosive primers, vacuum tube
getters and filaments. Zirconium dioxide (ZrO
2) is used in laboratory crucibles, metallurgical furnaces, and as a refractory material. 90% of all zirconium produced is used in nuclear reactors because of its low neutron-capture
cross-section and resistance to corrosion. Zirconium alloys are used in space vehicle parts for their resistance to heat, an important quality given the extreme heat associated with
atmospheric reentry. Zirconium is also a component in some
abrasives, such as grinding wheels and
sandpaper.
Refining
Upon being collected from coastal waters, the solid mineral
zircon is purified by spiral concentrators to remove excess sand and gravel and by magnetic separators to remove
ilmenite and
rutile. The byproducts can then be dumped back into the water safely, as they're all natural components of beach sand. The refined zircon is then purified into pure zirconium by
chlorine or other agents, then
sintered until sufficiently ductile for metalworking.
Arabic zarkûn from
Persian zargûn زرگون meaning "gold like")
Occurrence
Geological
Zirconium has a concentration of about 130 mg/kg within the earth's crust and about .026 μg/L in sea water, and annual worldwide zirconium production is approximately 900,000 metric tons.
Zircon is a by-product of the mining and processing of the
titanium minerals
ilmenite and
rutile, as well as
tin mining. From 2003 to 2007, zircon prices have steadily increased from $360 to $840 per metric ton. This metal is commercially produced mostly by the reduction of the zirconium(IV)
chloride with
magnesium metal in the
Kroll process. These properties make zirconia useful as a thermal barrier coating, though it's also a common
diamond substitute. Other inorganic zirconium compounds include zirconium (II) hydride, zirconium nitride, and
zirconium tetrachloride (ZrCl
4), which is used in the
Friedel-Crafts reaction.
Organozirconium chemistry is the study of compounds containing a
carbon-zirconium bond. These organozirconium compounds are often employed as polymerization catalysts. The first such compound was zirconocene dibromide, prepared in 1952 by
John M. Birmingham at Harvard University. Schwartz's reagent, prepared in 1970 by P. C. Wailes and H. Weigold, is a
metallocene used in
organic synthesis for transformations of
alkenes and
alkynes.
Isotopes
Naturally-occurring zirconium is composed of five isotopes.
90Zr,
91Zr, and
92Zr are stable.
94Zr has a half-life of 1.10 × 10
17 years.
96Zr has half-life of 2.4 × 10
19 years, making it the longest-lived radioisotope of zirconium. Of these natural isotopes,
90Zr is the most common, making up 51.45% of all zirconium.
96Zr is the least common, comprising only 2.80% of zirconium.
28 artificial isotopes of zirconium have been synthesized, ranging in atomic mass from 78 to 110.
93Zr is the longest-lived artificial isotope, with a half-life of 1.53 × 10
6 years.
110Zr, the heaviest isotope of Zirconium, is also the shortest-lived, with an estimated half-life of only 30 milliseconds. Radioactive isotopes at or above mass number 93 decay by
β-, whereas those at or below 89 decay by
β+. The only exception is
88Zr, which decays by
ε. Inhalation of zirconium compounds can cause skin and lung
granulomas. Zirconium aerosols can cause
pulmonary granulomas. Persistent exposure to zirconium tetrachloride resulted in increased mortality in rats and guinea pigs and a decrease of blood hemoglobin and red blood cells in dogs. OSHA recommends a 5 mg/m
3 time weighted average limit and a 10 mg/m
3 short-term exposure limit.
Further Information
Get more info on 'Zirconium'.
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