Zirconium 34422 226144382 2008-07-17T00:46:41Z 208.181.106.25 /* Refining */ {{infobox zirconium}} [[Image:Zirconium rod.jpg|thumb|right|Zirconium rod]] '''Zirconium''' ({{pronEng|zɚˈkoʊniəm}}, {{IPA|/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 [[Jöns Jakob Berzelius|Berzelius]]. Zirconium has no known biological role. Zirconium forms both [[inorganic chemistry|inorganic]] and [[organic chemistry|organic]] compounds, such as [[zirconium dioxide]] and [[zirconocene dibromide]], respectively. There are five naturally-occurring [[isotope]]s, 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 [[lustre (mineralogy)|lustrous]], grayish-white, soft, [[ductile]], and [[malleable]] metal which is solid at room temperature, though it becomes hard and [[brittle]] at lower purities.<ref name="nbb"/><ref name="madehow"/> In powder form, zirconium is highly flammable, but the solid form is far less prone to igniting.<ref name="CRC2008"/> Zirconium is highly resistant to corrosion by alkalis, acids, salt water, and other agents.<ref name="Los Alamos">{{cite web |title=Zirconium|publisher=Los Alamos Chemistry Division|date=2003-12-15|url=http://periodic.lanl.gov/elements/40.html| accessdate = 2008-02-12}}</ref> However, it will dissolve in [[hydrochloric acid|hydrochloric]] and [[sulfuric acid]], especially when [[fluorine]] is present.<ref name="Nostrand">{{Citation|contribution=Zirconium|year=2005|title=Van Nostrand's Encyclopedia of Chemistry| editor-last = Considine| editor-first = Glenn D.|pages=1778–1779|place=New York|publisher=Wylie-Interscience|isbn=0-471-61525-0 }}</ref> Alloys with zinc become magnetic below 35&nbsp;K.<ref name="CRC2008"/> The melting point of zirconium is at 1855°C, and the boiling point is at 4409°C.<ref name="CRC2008">{{Citation|contribution=Zirconium|year=2007–2008|title=CRC Handbook of Chemistry and Physics|editor-last=Lide|editor-first=David R.|volume=4|pages=42|place=New York|publisher=CRC Press|id=978-0-8493-0488-0}}</ref> 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]].<ref>{{cite web|last=Winter|first=Mark|title=Electronegativity (Pauling)|publisher=University of Sheffield| date = 2007| url = http://www.webelements.com/webelements/properties/text/image-flash/electroneg-pauling.html| accessdate = 2008-03-05}}</ref> ==Applications== Because of Zirconium's excellent resistance to corrosion, it is often used as an alloying agent in materials that are exposed to corrosive agents, such as surgical appliances, explosive primers, vacuum tube [[getter]]s and filaments. Zirconium dioxide (ZrO<sub>2</sub>) is used in laboratory crucibles, metallurgical furnaces, and as a refractory material.<ref name="CRC2008"/> Zircon (ZrSiO<sub>4</sub>) is cut into gemstones for use in jewelry. Zirconium carbonate (3ZrO<sub>2</sub>·CO<sub>2</sub>·H<sub>2</sub>O) was used in lotions to treat poison ivy, but this was discontinued as it caused bad skin reactions in some cases.<ref name="nbb">{{cite book| last = Emsley| first = John| title = Nature's Building Blocks| publisher = Oxford University Press| date = 2001| location = Oxford| pages = 506–510| isbn = 0-19-850341-5 }}</ref> 90% of all zirconium produced is used in nuclear reactors because of its low neutron-capture [[cross-section]] and resistance to corrosion.<ref name="CRC2008"/><ref name="madehow">{{cite web| title = Zirconium| work = How Products Are Made| publisher = Advameg Inc.| date = 2007| url = http://www.madehow.com/Volume-1/Zirconium.html| accessdate = 2008-03-26}}</ref> Zirconium alloys are used in space vehicle parts for their resistance to heat, an important quality given the extreme heat associated with [[atmospheric reentry]].<ref name="Stwertka">{{cite book|last=Stwertka|first=Albert|title=A Guide to the Elements|publisher=Oxford University Press|date=1996|pages=117–119| isbn = 0-19-508083-1}}</ref> Zirconium is also a component in some [[abrasive]]s, such as grinding wheels and [[sandpaper]].<ref name="greenwood">{{cite book|last=Krebs|first=Robert E.|title=The History and Use of our Earth's Chemical Elements|publisher=Greenwood Press|date=1998|location=Westport, Connecticut|pages=98–100|isbn=0-313-30123-9}}</ref> Zirconium is used in weapons such as the [[BLU-97/B Combined Effects Bomb]] for incendiary effect. ===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 are all natural components of beach sand. The refined zircon is then purified into pure zirconium by [[chlorine]] or other agents, then [[sinter]]ed until sufficiently ductile for metalworking.<ref name="madehow"/> Zirconium and [[hafnium]] are both contained in zircon and they are quite difficult to separate due to their similar chemical properties.<ref name="Stwertka"/> ==History== The zirconium-containing mineral [[zircon]], or its variations ([[jargoon]], hyacinth, [[jacinth]], ligure), were mentioned in biblical writings.<ref name="CRC2008"/><ref name="Stwertka"/> The mineral was not known to contain a new element until 1789,<ref name="greenwood"/> when [[Martin Heinrich Klaproth|Klaproth]] analyzed a jargoon from the island of [[Ceylon]] in the Indian Ocean. He named the new element Zirkonerde (zirconia).<ref name="Los Alamos"/><ref name="CRC2008"/> [[Humphry Davy]] attempted to isolate this new element in 1808 through electrolysis, but failed.<ref name="nbb"/> Zirconium (from [[Syriac language|Syriac]] ''zargono'',<ref>{{cite web| last = Pearse| first = Roger| title = Syriac Literature| date = 2002-09-16| url = http://www.tertullian.org/rpearse/oriental/syriac.htm| accessdate = 2008-02-11}}</ref> [[Arabic language|Arabic]] ''zarkûn'' from [[Persian language|Persian]] ''zargûn'' ''زرگون'' meaning "gold like")<ref name="Stwertka"/> was first isolated in an impure form in 1824 by [[Jöns Jakob Berzelius|Berzelius]] by heating a mixture of potassium and potassium-zirconium fluoride in a small decomposition process conducted in an iron tube.<ref name="Los Alamos"/><ref name="CRC2008"/> The ''[[crystal bar process]]'' (or ''Iodide process''), discovered by [[Anton Eduard van Arkel]] and Jan Hendrik de Boer in 1925, was the first industrial process for the commercial production of pure metallic zirconium. The process involved thermally decomposing zirconium tetraiodide. It was superseded in 1945 by a much cheaper [[Kroll process|process]] developed by [[William Justin Kroll]], in which zirconium tetrachloride is broken down by magnesium.<ref name="madehow"/><ref name="metal1998">{{Citation|first=James B.|last=Hedrick|contribution=Zirconium|title=Metal Prices in the United States through 1998|year=1998|pages=175–178|publisher=US Geological Survey|url=http://minerals.usgs.gov/minerals/pubs/metal_prices/metal_prices1998.pdf|format=[[PDF]]|accessdate=2008-02-26}}</ref> == Occurrence == === Geological === [[Image:2005zirconium.PNG|thumb|left|Zirconium output in 2005]] [[Image:Zirconium mineral concentrates - world production trend.svg|thumb|left|World production trend of zirconium mineral concentrates]] Zirconium has a concentration of about 130&nbsp;mg/kg within the earth's crust and about .026&nbsp;μg/L in sea water,<ref name="argonne"/> though it is never found in nature as a [[native metal]]. The principal commercial source of zirconium is the zirconium [[silicate mineral]], [[zircon]] (ZrSiO<sub>4</sub>),<ref name="nbb"/> which is found primarily in Australia, Brazil, India, Russia, South Africa, and the United States, as well as in smaller deposits around the world.<ref name="madehow"/> 80% of zircon mining occurs in Australia and South Africa.<ref name="nbb"/> [[Zircon]] resources exceed 60 million metric tons worldwide<ref name="usgs2008">{{cite journal| title = Zirconium and Hafnium| journal = Mineral Commodity Summaries| pages = 192–193| publisher = US Geological Survey| date = January 2008| url = http://minerals.usgs.gov/minerals/pubs/commodity/zirconium/mcs-2008-zirco.pdf| format = PDF| accessdate = 2008-02-24}}</ref> and annual worldwide zirconium production is approximately 900,000 metric tons.<ref name="argonne">{{Citation|first=John|last=Peterson|first2=Margaret|last2=MacDonell| contribution=Zirconium|title=Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas|year=2007|pages=64–65|publisher=Argonne National Laboratory|format=[[PDF]]|url=http://www.evs.anl.gov/pub/doc/ANL_ContaminantFactSheets_All_070418.pdf|accessdate=2008-02-26}}</ref> Zircon is a by-product of the mining and processing of the [[titanium]] minerals [[ilmenite]] and [[rutile]], as well as [[tin]] mining.<ref>{{cite web|last=Callaghan|first=R.|title=Zirconium and Hafnium Statistics and Information|publisher=US Geological Survey|date=2008-02-21|url=http://minerals.usgs.gov/minerals/pubs/commodity/zirconium/|accessdate=2008-02-24}}</ref> From 2003 to 2007, zircon prices have steadily increased from $360 to $840 per metric ton.<ref name="usgs2008"/> Zirconium also occurs in more than 140 other recognized mineral species including [[baddeleyite]] and [[kosnarite]].<ref>{{cite web|last=Ralph|first=Jolyon|coauthors=Ida Ralph|title=Minerals that include Zr|publisher=Mindat.org| date=2008|url=http://www.mindat.org/chemsearch.php?inc=Zr%2C&exc=&sub=Search+for+Minerals|accessdate=2008-02-23}}</ref> This metal is commercially produced mostly by the reduction of the zirconium(IV) [[chloride]] with [[magnesium]] metal in the [[Kroll process]].<ref name="CRC2008"/> Commercial-quality zirconium for most uses still has a content of 1% to 3% hafnium.<ref name="nbb"/> This element is relatively-abundant in [[Stellar classification#Class S|S-type stars]], and it has been detected in the sun and in meteorites. Lunar rock samples brought back from several [[Apollo program]] missions to the moon have a quite high zirconium oxide content relative to terrestrial rocks.<ref name="Los Alamos"/> ''See also [[:category:Zirconium minerals|zirconium minerals]].'' ===Biological=== Zirconium has no known biological role, though zirconium salts are of low toxicity. The human body contains, on average, only 1&nbsp;milligram of zirconium, and daily intake is approximately 50&nbsp;μg per day. Zirconium content in human blood is as low as 10 parts per billion. Aquatic plants readily take up soluble zirconium, but it is rare in land plants. 70% of plants have no zirconium content at all, and those that do have as little as 5 parts per billion.<ref name="nbb"/> ==Compounds== As a [[transition metal]], zirconium forms various [[inorganic chemistry|inorganic compounds]], such as [[zirconium dioxide]] (ZrO<sub>2</sub>). This compound, also referred to as ''zirconia'', has exceptional [[fracture toughness]] and chemical resistance, especially in its [[cubic zirconia|cubic]] form.<ref name="azomzirc">{{cite web|title=Zirconia| publisher = AZoM.com| date = 2008| url = http://www.azom.com/details.asp?ArticleID=133#_Key_Properties| accessdate=2008-03-17}}</ref> These properties make zirconia useful as a thermal barrier coating,<ref>{{cite journal|last=Gauthier| first=V.| last2=Dettenwanger|first2=F.|last3=Schütze|first3=M.|title=Oxidation behavior of γ-TiAl coated with zirconia thermal barriers| journal=Intermetallics| volume=10| issue=7|pages=667–674|publisher=Karl Winnacker Institut der Dechema|location= Frankfurt, Germany|date=2002-04-10| doi=10.1016/S0966-9795(02)00036-5}}</ref> though it is also a common [[diamond]] substitute.<ref name="azomzirc"/> [[Zirconium tungstate]] is an unusual substance in that it shrinks in all directions when heated, whereas other elements expand when heated.<ref name="CRC2008"/> ZrZn<sub>2</sub> is one of only two substances to exhibit [[superconductivity]] and [[ferromagnetism]] simultaneously, with the other being UGe<sub>2</sub>.<ref>{{cite journal|last=Day|first=Charles|title=Second Material Found that Superconducts in a Ferromagnetic State|journal=Physics Today|volume=54|issue=9|pages=16| publisher=American Institute of Physics |date=September 2001| issn=0031-9228|doi=10.1063/1.1420499}}</ref> Other inorganic zirconium compounds include zirconium(II) hydride, zirconium nitride, and [[zirconium tetrachloride]] (ZrCl<sub>4</sub>), which is used in the [[Friedel-Crafts reaction]].<ref>{{cite journal | author= Bora U.|title=Zirconium Tetrachloride|journal=[[Synlett]]|year=2003|pages=1073–1074|doi=10.1055/s-2003-39323}}</ref> [[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.<ref>{{cite journal|last=Rouhi|first=A. Maureen|title=Organozirconium Chemistry Arrives|journal=Science & Technology| volume=82|issue=16|pages=36–39|publisher=Chemical & Engineering News|date=2004-04-19|url=http://pubs.acs.org/cen/nlw/8216sci1.html|issn=0009-2347| accessdate=2008-03-17}}</ref> Schwartz's reagent, prepared in 1970 by P. C. Wailes and H. Weigold,<ref>{{cite journal|author=P. C. Wailes and H. Weigold|title=Hydrido complexes of zirconium I. Preparation|journal=[[Journal of Organometallic Chemistry]]|year=1970|volume=24|pages=405–411|doi=10.1016/S0022-328X(00)80281–8|doi_brokendate=2008-06-25}}</ref> is a [[metallocene]] used in [[organic synthesis]] for transformations of [[alkenes]] and [[alkynes]].<ref name=hart>{{cite journal | author=D. W. Hart and J. Schwartz| title=Hydrozirconation. Organic Synthesis via Organozirconium Intermediates. Synthesis and Rearrangement of Alkylzirconium(IV) Complexes and Their Reaction with Electrophiles| journal=[[J. Am. Chem. Soc.]]|volume=96 |issue=26|year=1974|pages=8115–8116|doi=10.1021/ja00833a048}}</ref> ==Isotopes== {{main|Isotopes of zirconium}} Naturally-occurring zirconium is composed of five isotopes. <sup>90</sup>Zr, <sup>91</sup>Zr, and <sup>92</sup>Zr are stable. <sup>94</sup>Zr has a half-life of 1.10×10<sup>17</sup>&nbsp;years. <sup>96</sup>Zr has half-life of 2.4×10<sup>19</sup>&nbsp;years, making it the longest-lived radioisotope of zirconium. Of these natural isotopes, <sup>90</sup>Zr is the most common, making up 51.45% of all zirconium. <sup>96</sup>Zr is the least common, comprising only 2.80% of zirconium.<ref name="nubase">{{cite journal|title=Nubase2003 Evaluation of Nuclear and Decay Properties|journal=Nuclear Physics A|volume=729|pages=3–128|publisher=Atomic Mass Data Center|date=2003|doi=10.1016/j.nuclphysa.2003.11.001|author=Audi, G}}</ref> 28 artificial isotopes of zirconium have been synthesized, ranging in atomic mass from 78 to 110. [[Zirconium-93|<sup>93</sup>Zr]] is the longest-lived artificial isotope, with a half-life of 1.53×10<sup>6</sup>&nbsp;years. <sup>110</sup>Zr, the heaviest isotope of zirconium, is also the shortest-lived, with an estimated half-life of only 30&nbsp;milliseconds. Radioactive isotopes at or above mass number 93 decay by [[beta decay|β<sup>−</sup>]], whereas those at or below 89 decay by [[beta decay|β<sup>+</sup>]]. The only exception is <sup>88</sup>Zr, which decays by [[electron capture|ε]].<ref name="nubase"/> Zirconium also has six [[nuclear isomer|metastable isomer]]s, <sup>83m</sup>Zr, <sup>85m</sup>Zr, <sup>89m</sup>Zr, <sup>90m1</sup>Zr, <sup>90m2</sup>Zr, and <sup>91m</sup>Zr. Of these, <sup>90m2</sup>Zr has the shortest halflife at 131&nbsp;nanoseconds. <sup>89m</sup>Zr is the longest lived with a half-life of 4.161&nbsp;minutes.<ref name="nubase"/> ==Toxicity== Ingestion or inhalation of <sup>93</sup>Zr, a radioactive isotope, causes a slight increase in the likelihood of developing cancer.<ref name="argonne"/> Short-term exposure to zirconium powder can cause irritation, but only contact with the eyes requires medical attention.<ref>{{Citation| contribution=Zirconium|title=International Chemical Safety Cards|date=October 2004|publisher=International Labour Organization|url=http://www.oit.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc14/icsc1405.htm|accessdate=2008-03-30}}</ref> Inhalation of zirconium compounds can cause skin and lung [[granuloma]]s. 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&nbsp;mg/m<sup>3</sup> [[permissible exposure limit|time weighted average]] limit and a 10&nbsp;mg/m<sup>3</sup> short-term exposure limit.<ref>{{cite web|title=Zirconium Compounds|publisher=National Institute for Occupational Health and Safety|date=2007-12-17|url=http://www.cdc.gov/niosh/pel88/7440-67.html|accessdate=2008-02-17}}</ref> ==See also== {{Commons|Zirconium}} {{wiktionary|zirconium}} *[[:Category:Zirconium compounds|Zirconium compounds]] ==Notes== {{reflist}} ==External links== *[http://webelements.com/zirconium/ WebElements.com: Zirconium] *[http://periodic.lanl.gov/elements/40.html Los Alamos National Laboratory: Zirconium] {{clear}} {{compact periodic table}} [[Category:Chemical elements]] [[Category:Transition metals]] [[Category:Zirconium|*]] [[Category:Pyrotechnic fuels]] {{Link FA|de}} <!-- interwiki --> [[af:Sirkonium]] [[ar:زركونيوم]] [[az:Sirkonium]] [[be:Цырконій]] [[bs:Cirkonijum]] [[ca:Zirconi]] [[cs:Zirkonium]] [[co:Zirconiu]] [[da:Zirconium]] [[de:Zirconium]] [[et:Tsirkoonium]] [[el:Ζιρκόνιο]] [[es:Circonio]] [[eo:Zirkonio]] [[eu:Zirkonio]] [[fa:زیرکونیوم]] [[fr:Zirconium]] [[fur:Zirconi]] [[gv:Shirconium]] [[ko:지르코늄]] [[hy:Ցիրկոնիում]] [[hi:जर्कोनियम]] [[hr:Cirkonij]] [[io:Zirkonio]] [[id:Zirkonium]] [[is:Sirkon]] [[it:Zirconio]] [[he:זירקוניום]] [[jv:Zirkonium]] [[kn:ಜಿರ್ಕೊನಿಯಮ್]] [[sw:Zirikoni]] [[ht:Zikonyòm]] [[ku:Zîrkonyûm]] [[la:Zirconium]] [[lv:Cirkonijs]] [[lb:Zirkonium]] [[lt:Cirkonis]] [[jbo:jinmrzirkoni]] [[hu:Cirkónium]] [[ml:സിര്‍കോണിയം]] [[nl:Zirkonium]] [[ja:ジルコニウム]] [[no:Zirkonium]] [[nn:Zirkonium]] [[oc:Zircòni]] [[uz:Sirkoniy]] [[pl:Cyrkon (pierwiastek)]] [[pt:Zircônio]] [[ro:Zirconiu]] [[ru:Цирконий]] [[scn:Zirconiu]] [[simple:Zirconium]] [[sk:Zirkónium]] [[sl:Cirkonij]] [[sr:Цирконијум]] [[sh:Cirkonijum]] [[fi:Zirkonium]] [[sv:Zirkonium]] [[th:เซอร์โคเนียม]] [[vi:Zirconi]] [[tr:Zirkonyum]] [[uk:Цирконій]] [[zh:锆]]