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   V

VANADIUM

(Scandinavia Vanadis, Scandinavian goddess)

V  at. wt. 50.942
   at. no. 23
   m.p.  1890°C
   b.p.  3380°C 
   sp.gr. 6.11 (18°C)
   valence 2, 3, 4, or 5. 

VANADIUM (Scandinavian goddess, Vanadis), V; at. wt. 50.942; at. no.23; m.p. 18900t 100C; h.p. 33800C; sp. gr. C ~ C ITIE ELEMENlw}Cmtinued) 6.11 (18.70C); valence 2, 3, 4, or 5. Vanadium was first dis- covered by del Rio in 1801. Unfortunately a French chemist incorrectly declared del Rio's new element was only impure chromium; del Rio thought himself to be mistaken and accepted the French chemist's statement. The element was rediscovered in 1830 by Sefstrdm who named the element in honor of the Scandinavian goddess Vanadis because of its beautiful multi-colored compounds. It was isolated in nearly pure form by Roscoe, in 1867, who reduced the chloride with hydrogen. Vanadium of 99.3 to 99.8% purity was not produced until 1927. Vanadium is found in about 65 different minerals among which are carnotite, roscoelite, vanadinite, and patronite-important sources of the metal. Vanadium is also found in phosphate rock, certain iron ores, and is present in some crude oils in the form of organic complexes. It is also found in small percentages in meteorites. Commercial production from petroleum ash holds prqmise as an important source of the element. High-purity ductile vanadium can be obtained by reduction of vanadium trj- chloride with magnesium or with magnesium-sodium mix- tures. Much of the vanadium metal being produced is now made by calcium reduction of V205 in a pressure vessel, an adaption of a process developed by McKechnie and Seybolt. -Natural vanadium is a mixture of two isotopes V50 (0.24%) and V51 (99.76%). V50 is slightly radioactive, having a half-life of 6 x 1015 yrs. Seven other unstable isotopes are recognized. Pure vanadium is a bright white metal, and is soft and ductile. It has good corrosion resistance to -alkalis, sulfuric and hydrochloric acid, and salt waters, burthe metal oxidizes readily above 6600C. The metal has good structural strength and a low-fission neutron cross section, making it useful in nuclear applications. Vanadium is used in produc- ing rust-resistant, spring, and high-speed tool steels. It is an important carbide stabilizer in making steels. About 80% of the vanadium now produced is used as ferro- vanadium or as a steel additive. Vanadium foil is used as a bonding agent in cladding titanium to steel. Vanadinin pentoxide is used in ceramics and as a catalyst. It is also used as a mordant in dyeing and printing fabrics and in the manufacture of aniline black. Vanadium and its compounds are toxic and should be handled with care. It has been re- ported that small doses - of vanadium salts have reversed hardening of arteries in experimental animals, and that workers engaged in vanadium mining and milling operations have a lower serum cholesterol than unexposed workers in the same area. The maximum allowable concentration of V205 dust in air is about 0.5 mg/cu meter; V2O5 fumes should not exceed about 0.1 mg/cu meter of air. Ductile vanadium is commercially available at a cost of about $40/lb. Commercial vanadium metal, of about 95% purity, costs about $5/lb. -

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