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Production

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Vanadium metal is obtained by a multistep process that begins with roasting crushed ore with NaCl or Na2CO3 at about 850 °C to give sodium metavanadate (NaVO3). 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.[1] 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:[2]

2 V + 3 I2 ⇌ 2 VI3
Ferrovanadium chunks

Most vanadium is used as 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.[1]

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,[3] 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.[4]

After the separation from the other minerals, the mixed oxides of tantalum Ta2O5 and niobium Nb2O5 are obtained. To produce niobium, the first step in the processing is the reaction of the oxides with hydrofluoric acid:[5]

Ta2O5 + 14 HF → 2 H2[TaF7] + 5 H2O
Nb2O5 + 10 HF → 2 H2[NbOF5] + 3 H2O

The first industrial scale separation, developed by Swiss chemist de Marignac, exploits the differing solubilities of the complex niobium and tantalum fluorides, dipotassium oxypentafluoroniobate monohydrate (K2[NbOF5]·H2O) and dipotassium heptafluorotantalate (K2[TaF7]) in water. Newer processes use the liquid extraction of the fluorides from aqueous solution by organic solvents like cyclohexanone.[5] The complex niobium and tantalum fluorides are extracted separately from the organic solvent with water and either precipitated by the addition of potassium fluoride to produce a potassium fluoride complex, or precipitated with ammonia as the pentoxide:[6]

H2[NbOF5] + 2 KF → K2[NbOF5]↓ + 2 HF

Followed by:

2 H2[NbOF5] + 10 NH4OH → Nb2O5↓ + 10 NH4F + 7 H2O

Several methods are used for the reduction to metallic niobium. The electrolysis of a molten mixture of K2[NbOF5] and sodium chloride is one; the other is the reduction of the fluoride with sodium. With this method, a relatively high purity niobium can be obtained. In large scale production, Nb2O5 is reduced with hydrogen or carbon.[6] In the aluminothermic reaction, a mixture of iron oxide and niobium oxide is reacted with aluminium:

3 Nb2O5 + Fe2O3 + 12 Al → 6 Nb + 2 Fe + 6 Al2O3

Small amounts of oxidizers like sodium nitrate are added to enhance the reaction. The result is aluminium oxide and ferroniobium, an alloy of iron and niobium used in steel production.[7][8] Ferroniobium contains between 60 and 70% niobium.[9] Without iron oxide, the aluminothermic process is used to produce niobium. Further purification is necessary to reach the grade for superconductive alloys. Electron beam melting under vacuum is the method used by the two major distributors of niobium.[10][11]

As of 2013, CBMM from Brazil controlled 85 percent of the world's niobium production.[12] The United States Geological Survey estimates that the production increased from 38,700 tonnes in 2005 to 44,500 tonnes in 2006.[13][14] Worldwide resources are estimated to be 4.4 million tonnes.[14] During the ten-year period between 1995 and 2005, the production more than doubled, starting from 17,800 tonnes in 1995.[15] Between 2009 and 2011, production was stable at 63,000 tonnes per year,[16] with a slight decrease in 2012 to only 50,000 tonnes per year.[17]

Mine production (t)[18] (USGS estimate)[19][20]
Country 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
 Australia 160 230 290 230 200 200 200 ? ? ? ? ? ? ? ? ? ? ? ? ?
 Brazil 30,000 22,000 26,000 29,000 29,900 35,000 40,000 57,300 58,000 58,000 58,000 58,000 63,000 53,100 53,000 58,000 57,000 60,700 59,000 88,900
 Canada 2,290 3,200 3,410 3,280 3,400 3,310 4,167 3,020 4,380 4,330 4,420 4,630 5,000 5,260 5,000 5,750 6,100 6,980 7,700 6,800
 Congo D.R. ? 50 50 13 52 25 ? ? ? ? ? ? ? ? ? ? ? ? ? ?
 Mozambique ? ? 5 34 130 34 29 ? ? 4 10 29 30 20 ? ? ? ? ?
 Nigeria 35 30 30 190 170 40 35 ? ? ? ? ? ? ? ? 29 104 122 181 150
 Rwanda 28 120 76 22 63 63 80 ? ? ? ? ? ? ? ? ? ? ? ? ?
World 32,600 25,600 29,900 32,800 34,000 38,700 44,500 60,400 62,900 62,900 62,900 63,000 50,100 59,400 59,000 64,300 63,900 69,100 68,200 97,000

Lesser amounts are found in Malawi's Kanyika Deposit (Kanyika mine).

70000 t of tantalum ore are produced yearly. Brazil produces 90% of tantalum ore, with Canada, Australia, China, and Rwanda also producing the element. The demand for tantalum is around 1200 t per year.[4]

  1. ^ a b Moskalyk, R. R.; Alfantazi, A. M. (2003). "Processing of vanadium: a review". Minerals Engineering. 16 (9): 793–805. doi:10.1016/S0892-6875(03)00213-9.
  2. ^ Carlson, O. N.; Owen, C. V. (1961). "Preparation of High-Purity Vanadium Metals by the Iodide Refining Process". Journal of the Electrochemical Society. 108: 88. doi:10.1149/1.2428019.
  3. ^ USGS Vanadinum Production Statistics[permanent dead link‍]
  4. ^ a b Cite error: The named reference Emsley was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference ICE was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference HollemanAF was invoked but never defined (see the help page).
  7. ^ Tither, Geoffrey (2001). Minerals, Metals and Materials Society (ed.). Progress in Niobium Markets and Technology 1981–2001 (PDF). ISBN 978-0-9712068-0-9. Archived from the original (PDF) on 17 December 2008. {{cite book}}: |journal= ignored (help)
  8. ^ Dufresne, Claude; Goyette, Ghislain (2001). Minerals, Metals and Materials Society (ed.). The Production of Ferroniobium at the Niobec mine 1981–2001 (PDF). ISBN 978-0-9712068-0-9. Archived from the original (PDF) on 17 December 2008. {{cite book}}: |journal= ignored (help)
  9. ^ Cite error: The named reference tesla was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Aguly was invoked but never defined (see the help page).
  11. ^ Choudhury, Alok; Hengsberger, Eckart (1992). "Electron Beam Melting and Refining of Metals and Alloys". The Iron and Steel Institute of Japan International. 32 (5): 673–681. doi:10.2355/isijinternational.32.673.
  12. ^ Lucchesi, Cristane; Cuadros, Alex (April 2013), "Mineral Wealth", Bloomberg Markets (paper), p. 14
  13. ^ Papp, John F. "Niobium (Columbium)" (PDF). USGS 2006 Commodity Summary. Archived (PDF) from the original on 17 December 2008. Retrieved 20 November 2008.
  14. ^ a b Papp, John F. "Niobium (Columbium)" (PDF). USGS 2007 Commodity Summary. Archived (PDF) from the original on 5 August 2017. Retrieved 20 November 2008.
  15. ^ Papp, John F. "Niobium (Columbium)" (PDF). USGS 1997 Commodity Summary. Archived (PDF) from the original on 11 January 2019. Retrieved 20 November 2008.
  16. ^ Niobium (Colombium) Archived 8 July 2012 at the Wayback Machine U.S. Geological Survey, Mineral Commodity Summaries, January 2011
  17. ^ Niobium (Colombium) Archived 6 March 2016 at the Wayback Machine U.S. Geological Survey, Mineral Commodity Summaries, January 2016
  18. ^ Cunningham, Larry D. (5 April 2012). "USGS Minerals Information: Niobium (Columbium) and Tantalum". Minerals.usgs.gov. Archived from the original on 28 January 2013. Retrieved 17 August 2012.
  19. ^ "Niobium (Columbium) and Tantalum Statistics and Information | U.S. Geological Survey". Archived (PDF) from the original on 6 March 2019. Retrieved 2 December 2021.
  20. ^ "Nigeria: Production volume of niobium". Archived from the original on 2 December 2021. Retrieved 2 December 2021.
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