Editing Zirconium (section)

==Production==

=== Occurrence ===
[[File:2005zirconium.PNG|thumb|Zirconium output in 2005]]
Zirconium is a by-product formed after 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/|access-date=2008-02-24}}</ref> From 2003 to 2007, while prices for the mineral zircon steadily increased from $360 to $840 per tonne, the price for unwrought zirconium metal decreased from $39,900 to $22,700 per ton. Zirconium metal is much more expensive than [[zircon]] because the reduction processes are costly.<ref name="usgs2008" />

Collected from coastal waters, zircon-bearing sand is purified by [[spiral separator#Wet Spiral Separators|spiral concentrators]] to separate lighter materials, which are then returned to the water because they are natural components of beach sand. Using [[magnetic separation]], the titanium ores [[ilmenite]] and [[rutile]] are removed.<ref>{{Cite journal |last1=Siddiqui |first1=A. S. |last2=Mohapatra |first2=A. K. |last3=Rao |first3=J. V. |date=2000 |title=Separation of beach sand minerals |url=https://core.ac.uk/download/pdf/297712279.pdf |journal=Processing of Fines |location=India |volume=2 |pages=114–126 |isbn=81-87053-53-4}}</ref><!--Rutile is nonmagnetic, maybe has Fe impurities?-->

Most zircon is used directly in commercial applications, but a small percentage is converted to the metal. Most Zr metal is produced by the reduction of the [[zirconium(IV) chloride]] with [[magnesium]] metal in the [[Kroll process]].<ref name="CRC2008" /> The resulting metal is [[sintering|sintered]] until sufficiently ductile for metalworking.<ref name="madehow" />

===Separation of zirconium and hafnium===
Commercial zirconium metal typically contains 1–3% of [[hafnium]],<ref name="Ullmann" /> which is usually not problematic because the chemical properties of hafnium and zirconium are very similar. Their neutron-absorbing properties differ strongly, however, necessitating the separation of hafnium from zirconium for nuclear reactors.<ref name="Stwertka" /> Several separation schemes are in use.<ref name="Ullmann">Nielsen, Ralph (2005) "Zirconium and Zirconium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a28_543}}</ref> The [[liquid-liquid extraction]] of the [[thiocyanate]]-oxide derivatives exploits the fact that the hafnium derivative is slightly more soluble in [[methyl isobutyl ketone]] than in water. This method accounts for roughly two-thirds of pure zirconium production,<ref>{{Cite journal |last1=Wu |first1=Ming |last2=Xu |first2=Fei |last3=Dong |first3=Panfei |last4=Wu |first4=Hongzhen |last5=Zhao |first5=Zhiying |last6=Wu |first6=Chenjie |last7=Chi |first7=Ruan |last8=Xu |first8=Zhigao |date=January 2022 |title=Process for synergistic extraction of Hf(IV) over Zr(IV) from thiocyanic acid solution with TOPO and N1923 |url=https://linkinghub.elsevier.com/retrieve/pii/S0255270121003615 |journal=Chemical Engineering and Processing - Process Intensification |language=en |volume=170 |pages=108673 |doi=10.1016/j.cep.2021.108673|bibcode=2022CEPPI.17008673W }}</ref> though other methods are being researched;<ref name=":0">{{Cite journal |last1=Xiong |first1=Jing |last2=Li |first2=Yang |last3=Zhang |first3=Xiaomeng |last4=Wang |first4=Yong |last5=Zhang |first5=Yanlin |last6=Qi |first6=Tao |date=2024-03-25 |title=The Extraction Mechanism of Zirconium and Hafnium in the MIBK-HSCN System |journal=Separations |language=en |volume=11 |issue=4 |pages=93 |doi=10.3390/separations11040093 |issn=2297-8739 |doi-access=free}}</ref> for instance, in India, a TBP-nitrate solvent extraction process is used for the separation of zirconium from other metals.<ref>{{Cite journal |last1=Pandey |first1=Garima |last2=Darekar |first2=Mayur |last3=Singh |first3=K.K. |last4=Mukhopadhyay |first4=S. |date=2023-11-02 |title=Selective extraction of zirconium from zirconium nitrate solution in a pulsed stirred column |url=https://www.tandfonline.com/doi/full/10.1080/01496395.2023.2232102 |journal=Separation Science and Technology |language=en |volume=58 |issue=15–16 |pages=2710–2717 |doi=10.1080/01496395.2023.2232102 |issn=0149-6395}}</ref> Zr and Hf can also be separated by [[fractional crystallization (chemistry)|fractional crystallization]] of potassium hexafluorozirconate (K<sub>2</sub>ZrF<sub>6</sub>), which is less soluble in water than the analogous hafnium derivative. [[Fractional distillation]] of the tetrachlorides, also called [[extractive distillation]], is also used.<ref name=":0" /><ref>{{Cite book |last1=Xu |first1=L. |last2=Xiao |first2=Y. |last3=van Sandwijk |first3=A. |last4=Xu |first4=Q. |last5=Yang |first5=Y. |chapter=Separation of Zirconium and Hafnium: A Review |date=2016 |title=Energy Materials 2014 |chapter-url=https://link.springer.com/chapter/10.1007/978-3-319-48765-6_53 |language=en |location=Cham |publisher=Springer International Publishing |pages=451–457 |doi=10.1007/978-3-319-48765-6_53 |isbn=978-3-319-48765-6}}</ref>

Vacuum [[Electric arc furnace|arc melting]], combined with the use of hot extruding techniques and [[Supercooling|supercooled]] copper hearths, is capable of producing zirconium that has been purified of oxygen, nitrogen, and carbon.<ref>{{Cite book |last=Shamsuddin |first=Mohammad |url=https://link.springer.com/book/10.1007/978-3-030-58069-8 |title=Physical Chemistry of Metallurgical Processes |series=The Minerals, Metals & Materials Series |date=22 June 2021 |publisher=Springer Cham |isbn=978-3-030-58069-8 |edition=2nd |pages=1-5, 390-391 |language=en |doi=10.1007/978-3-030-58069-8}}</ref>

Hafnium must be removed from zirconium for nuclear applications because hafnium has a neutron absorption cross-section 600 times greater than zirconium.<ref name="b1">{{cite book|author=Brady, George Stuart|author2=Clauser, Henry R.|author3=Vaccari, John A.|name-list-style=amp |title=Materials handbook: an encyclopedia for managers, technical professionals, purchasing and production managers, technicians, and supervisors|url=https://books.google.com/books?id=vIhvSQLhhMEC&pg=PA1063|access-date=2011-03-18 |year=2002|publisher=McGraw-Hill Professional|isbn=978-0-07-136076-0|pages=1063–}}</ref> The separated hafnium can be used for reactor [[control rods]].<ref>{{cite book|author=Zardiackas, Lyle D.|author2=Kraay, Matthew J.|author3=Freese, Howard L.|name-list-style=amp |title=Titanium, niobium, zirconium and tantalum for medical and surgical applications|url=https://books.google.com/books?id=iAlt_F5K9KkC&pg=PA21|access-date=2011-03-18 |year= 2006|publisher=ASTM International|isbn=978-0-8031-3497-3|pages=21–}}</ref>