Editing Group 5 element (section)

=== Vanadium ===

Vanadium metal is obtained by a multistep process that begins with roasting crushed ore with [[sodium chloride|NaCl]] or [[sodium carbonate|Na<sub>2</sub>CO<sub>3</sub>]] at about 850&nbsp;°C to give [[sodium metavanadate]] (NaVO<sub>3</sub>). An aqueous extract of this solid is acidified to produce "red cake", a polyvanadate salt, which is reduced with [[calcium]] metal. As an alternative for small-scale production, vanadium pentoxide is reduced with [[hydrogen]] or [[magnesium]]. Many other methods are also used, in all of which vanadium is produced as a [[byproduct]] of other processes.<ref name="Moskalyk">{{cite journal|journal= Minerals Engineering|volume= 16|pages= 793–805|doi= 10.1016/S0892-6875(03)00213-9|first= R. R.|last= Moskalyk|author2=Alfantazi, A. M. |title= Processing of vanadium: a review|date= 2003|issue= 9|bibcode= 2003MiEng..16..793M}}</ref> Purification of vanadium is possible by the [[crystal bar process]] developed by [[Anton Eduard van Arkel]] and [[Jan Hendrik de Boer]] in 1925. It involves the formation of the metal iodide, in this example [[vanadium(III) iodide]], and the subsequent decomposition to yield pure metal:<ref>{{cite journal|title= Preparation of High-Purity Vanadium Metals by the Iodide Refining Process|journal= Journal of the Electrochemical Society|volume= 108|page=88|date= 1961|first= O. N.|last= Carlson|author2=Owen, C. V. |doi= 10.1149/1.2428019}}</ref>
:2 V + 3 I<sub>2</sub> {{eqm}} 2 VI<sub>3</sub>

[[File:FerroVanadium.jpg|thumb|Ferrovanadium chunks]]

Most vanadium is used as a component of a [[steel]] alloy called [[ferrovanadium]]. Ferrovanadium is produced directly by reducing a mixture of vanadium oxide, iron oxides and iron in an electric furnace. The vanadium ends up in [[pig iron]] produced from vanadium-bearing magnetite. Depending on the ore used, the slag contains up to 25% of vanadium.<ref name="Moskalyk" />

Approximately 70000 [[tonnes]] of vanadium ore are produced yearly, with 25000 t of vanadium ore being produced in Russia, 24000 in [[South Africa]], 19000 in China, and 1000 in [[Kazakhstan]]. 7000 t of vanadium metal are produced each year. It is impossible to obtain vanadium by heating its ore with carbon. Instead, vanadium is produced by heating [[vanadium oxide]] with calcium in a [[pressure vessel]]. Very high-purity vanadium is produced from a reaction of [[vanadium trichloride]] with magnesium.<ref name = "Emsley"/>