Editing Titanium (section)

===Purification processes===
{{see also|Category:Titanium processes}}
{{also|Category:Titanium companies}}
====Hunter process====
The Hunter process was the first industrial process to produce pure metallic titanium. It was invented in 1910 by [[Matthew A. Hunter]], a [[chemist]] born in New Zealand who worked in the United States.<ref>{{cite journal | last1 = Hunter | first1 = M. A. | year = 1910| title = Metallic Titanium | url = | journal = J. Am. Chem. Soc. | volume =  32| issue = 3| pages =  330–336| doi = 10.1021/ja01921a006 | bibcode = 1910JAChS..32..330H }}</ref> The process involves reducing [[titanium tetrachloride]] (TiCl<sub>4</sub>) with [[sodium]] (Na) in a batch reactor with an inert atmosphere at a temperature of 1,000&nbsp;°C. Dilute [[hydrochloric acid]] is then used to leach the salt from the product.<ref>{{Cite encyclopedia |entry=Hunter process |dictionary=A Dictionary of Chemical Engineering |date=2014 |url=http://www.oxfordreference.com/view/10.1093/acref/9780199651450.001.0001/acref-9780199651450-e-1447 |url-access=subscription |language=en|doi=10.1093/acref/9780199651450.001.0001|last1=Schaschke |first1=Carl |publisher=Oxford University Press |isbn=978-0-19-965145-0 }}</ref> 
:TiCl<sub>4</sub>(g)  +  4 Na(l)   →   4 NaCl(l)  + Ti(s)

====Kroll process====
[[File:Sample of Titanium tetrachloride 01.jpg|thumb|right|Sample of Titanium tetrachloride]]
The processing of titanium metal occurs in four major steps: reduction of titanium ore into "sponge", a porous form; melting of sponge, or sponge plus a master alloy to form an ingot; primary fabrication, where an ingot is converted into general mill products such as [[bar stock|billet]], bar, [[plate (metal)|plate]], [[sheet metal|sheet]], strip, and [[tube (fluid conveyance)|tube]]; and secondary fabrication of finished shapes from mill products.<ref>{{harvnb|Donachie|1988|loc=Ch. 4}}</ref>

Because it cannot be readily produced by reduction of titanium dioxide,<ref name=Stwertka1998/> titanium metal is obtained by reduction of [[titanium tetrachloride]] (TiCl<sub>4</sub>) with magnesium metal in the Kroll process. The complexity of this batch production in the Kroll process explains the relatively high market value of titanium,<ref name=Barksdale1968p733>{{harvnb|Barksdale|1968|p=733}}</ref> despite the Kroll process being less expensive than the Hunter process.<ref name=Roza2008p9/> To produce the TiCl<sub>4</sub> required by the Kroll process, the dioxide is subjected to [[carbothermic reduction]] in the presence of [[chlorine]]. In this process, the chlorine gas is passed over a red-hot mixture of rutile or ilmenite in the presence of carbon.
After extensive purification by [[fractional distillation]], the TiCl<sub>4</sub> is reduced with {{convert|800|C}} molten magnesium in an [[argon]] atmosphere.<ref name=TICE6th/>
:<chem>2FeTiO3 + 7Cl2 + 6C ->[900^oC] 2FeCl3 + 2TiCl4 + 6CO</chem>
:<chem>TiCl4 + 2Mg ->[1100^oC] Ti + 2MgCl2</chem>

====Arkel-Boer process====
The [[van Arkel–de Boer process]] was the first semi-industrial process for pure Titanium. It involves thermal decomposition of [[titanium tetraiodide]].

====Armstrong process====
[[Titanium powder]] is manufactured using a [[flow production]] process known as the [[Armstrong process]]<ref name=Roza2008p25>{{harvnb|Roza|2008|p=25}}</ref> that is similar to the batch production [[Hunter process]]. A stream of titanium tetrachloride gas is added to a stream of molten sodium; the products (sodium chloride salt and titanium particles) is filtered from the extra sodium. Titanium is then separated from the salt by water washing. Both sodium and chlorine are recycled to produce and process more titanium tetrachloride.<ref name="ECI online">{{cite web |title=Titanium |date=15 January 2015 |website=The Essential Chemical Industry online |series=CIEC Promoting Science |publisher=[[University of York]] |location=York, UK |url=http://www.essentialchemicalindustry.org/metals/titanium.html}}</ref>