Vanadium

Vanadium is a chemical element that is useful in industrial processes as well as playing a number of roles in biological systems. In certain organisms vanadium is used in haloperoxidase and nitrogenase enzymes. Many sea squirts accumulate vanadium in very high concentrations, although the reason isn't known. The Amanita muscaria mushrooms also accumulate vanadium as a metal complex called amavadin, whose function is also unknown. Finally, a number of vanadium complexes have been shown to mitigate many of the symptoms of diabetes in both vitro and vivo studies. These complexes are being studied as potential alternatives to insulin therapy.

Exposure to high levels of vanadium can cause harmful health effects to lungs, throat, and eyes. Workers who breathed it for short and long periods sometimes had lung irritation, coughing, wheezing, chest pain, runny nose, and sore throats. These effects stopped as soon as they stopped breathing the contaminated air. Similar effects were observed through animal studies, and no other significant health effects of vanadium have been found in people.

Properties
Vanadium is a rare, soft, ductile gray-white element. Vanadium occurs in certain minerals and is used mainly to produce certain alloys. The surface of vanadium resists corrosion due to a protective film of oxide. Common oxidation states of vanadium include +2, +3, +4 and +5.

Pure Vanadium:


 * Is Bright white in appearance
 * Is Soft
 * Is Ductile
 * Has good structural strength
 * Possesses good corrosion resistance to alkalis, sulphuric acid, hydrochloric acid and salt water
 * Oxidises easily at temperatures higher than 660°C
 * Has a low fission neutron cross section

Occurrences
Vanadium is found in almost 54 different minerals as well as phosphate rock, some certain iron ores, and crude oils (in the form of complexes) and meteorites. Some of the more important minerals in which vanadium is found include vanadinite, roscoelite, carnotite, bauxite and patronite. Vanadium is never found free in nature but occurs in about 65 different minerals. Vanadium occurs in carbon containing deposits such as crude oil, coal, oil shale and tar sands.

Uses
Most of the vanadium produced (about 80%) is used as a steel additive called ferrovanadium. Mixed with aluminium in titanium alloys it is used in jet engines and high speed air-frames, with steel alloys it is used in axles, crankshafts, gears and other critical components. Vanadium alloys are also used in nuclear reactors because vanadium has low neutron-adsorption characteristics and it does not deform by creeping under high temperatures. Vanadium oxide (V2O5) is used as a catalyst in manufacturing sulfuric acid and malefic anhydride and in making ceramics. It is added to glass to produce green or blue tint. Glass coated with vanadium dioxide (VO2) can block infrared radiation at some specific temperatures.

Vanadium is also used for the production of rust resistant, spring and high speed, tool steels. It is also added to steels to stabilise carbides.

Vanadium foil is used to bond steel with titanium.

Vanadium compounds are also used in many applications such as:


 * Vanadium pentoxide as a catalyst in the ceramics industry
 * As a mordent in the printing and dyeing of fabrics
 * In the manufacture of aniline black

History


Vanadium was discovered by del Rio, in 1801. At that time, a French chemist refused to accept his discovery, thinking he had merely found impure chromium. Sefstrom later rediscovered the element in 1830 and named it after the Scandinavian goddess Vanadis, due to its attractive colours formed by different compounds.

However it was not until 1867, that Roscoe reduced the chloride of Vanadium with hydrogen to isolate the first sample of vanadium. It took another 60 years before vanadium was produced with purities as high as 99.3 to 99.8%.