Vanadium

Vanadium

Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The element is found only in chemically combined form in nature, but once isolated artificially, the formation of an oxide layer stabilizes the free metal somewhat against further oxidation. Andrés Manuel del Río discovered compounds of vanadium in 1801 by analyzing a new lead-bearing mineral he called "brown lead," and presumed its qualities were due to the presence of a new element, which he named erythronium (Greek for "red") since, upon heating, most of its salts turned from their initial color to red. Four years later, however, he was convinced by other scientists that erythronium was identical to chromium. Chlorides of vanadium were generated in 1830 by Nils Gabriel Sefström who thereby proved that a new element was involved, which he named "vanadium" after the Germanic goddess of beauty and fertility, Vanadís (Freyja). Both names were attributed to the wide range of colors found in vanadium compounds. Del Rio's lead mineral was later renamed vanadinite for its vanadium content. Although Berzelius claimed to have first isolated vanadium in the 1830s, in 1867 Henry Enfield Roscoe showed that he had only obtained the oxide, and finally in 1869 Roscoe demonstrated a method to obtain the pure element.
Vanadium occurs naturally in about 65 different minerals and in fossil fuel deposits. It is produced in China and Russia from steel smelter slag; other countries produce it either from the flue dust of heavy oil, or as a byproduct of uranium mining. It is mainly used to produce specialty steel alloys such as high speed tool steels. The most important industrial vanadium compound, vanadium pentoxide, is used as a catalyst for the production of sulfuric acid.

Large amounts of vanadium ions are found in a few organisms, possibly as a toxin. The oxide and some other salts of vanadium have moderate toxicity. Particularly in the ocean, vanadium is used by some life forms as an active center of enzymes, such as the vanadium bromoperoxidase of some ocean algae. Vanadium is probably a micronutrient in mammals, including humans, but its precise role in this regard is unknown.

Occurrence


Metallic vanadium is not found in nature, but is known to exist in about 65 different minerals. Economically significant examples include patronite (VS4),[23] vanadinite (Pb5(VO4)3Cl), and carnotite (K2(UO2)2(VO4)2·3H2O). Much of the world's vanadium production is sourced from vanadium-bearing magnetite found in ultramafic gabbro bodies. Vanadium is mined mostly in South Africa, north-western China, and eastern Russia. In 2010 these three countries mined more than 98% of the 56,000 tonnes of produced vanadium.

Vanadium is also present in bauxite and in fossil fuel deposits such as crude oil, coal, oil shale and tar sands. In crude oil, concentrations up to 1200 ppm have been reported. When such oil products are burned, the traces of vanadium may initiate corrosion in motors and boilers. An estimated 110,000 tonnes of vanadium per year are released into the atmosphere by burning fossil fuels. Vanadium has also been detected spectroscopically in light from the Sun and some other stars.

Symbol		V
Atomic Number		23
Atomic Weight		50.9415
Oxidation States		+2,+3,+4.+5
Electronegativity, Pauling		1.63
State at RT		Solid, Metal
Melting Point, K		2160
Boiling Point, K		3650

Appearance and Characteristics

Harmful effects:

Although vanadium is an essential trace element for some creatures a number of its compounds are toxic.

Generally, the higher the oxidation state of vanadium, the more toxic the compound.

Characteristics:

• Vanadium is a bright white, soft, ductile metal with good structural strength.
• Vanadium is resistant to attack by alkalis, hydrochloric acid, sulfuric acid, and salt water.
• When present in compounds, vanadium exists mostly in the oxidation state V.
• The metal oxidizes in air at around 660 oC to the pentoxide (V2O5).

Uses of Vanadium

• The main use of vanadium is in alloys, especially with steel.
• 85% of all the vanadium produced goes into steel, 10% goes into alloys of titanium and 5% into all other uses. 7
• A small amount of vanadium adds strength, toughness, and heat resistance.
• It is usually added in the form of ferrovanadium, a vanadium-iron alloy.
• Vanadium steel alloys are used in gears, axles and crankshafts.
• Titanium-aluminum-vanadium alloy is used in jet engines and for high-speed aircraft.
• Vanadium foil is used in cladding titanium to steel.
• Vanadium-gallium tape is used in superconducting magnets.
• Vanadium pentoxide is used in ceramics and as a catalyst for the production of sulfuric acid.
• The first extensive industrial use of vanadium metal was over a century ago in the vanadium-steel alloy chassis of the Ford Model T car.
• A 1908 advertisement for the Model T read, “Vanadium steel, the strongest, toughest and most enduring steel ever manufactured, is used throughout the entire car.”