V - Vanadium
|Chemical Element||Vanadium||Melting Point °C||1887|
|Chemical Symbol||V||Boiling Point °C||3377|
|Atomic Number||23||Density g/cm3||6.1|
Vanadium is a shiny, silvery metal, which comes at the head of Group 5 of the Periodic Table. It is the 19th most abundant element in the Earth’s crust. Vandium is extremely resistant to corrosion, as it is protected by a thin layer of oxide on its surface. The metal is attacked by concentrated acids but not by alkalis, even when they are molten. Iron, when alloyed with a few percent of vanadium makes a very strong alloy, even stronger than its neighbour, titanium. This alloy gives to the steel properties that iron alone would not have. i.e. such steels are rust-proof, shock-resistant and vibration resistant.
Vanadium was discovered twice independently. The first time was in 1801 by Andres Manuel Del Rio, a Professor of Mineralogy in Mexico City. Del Rio discovered it in a mineral named vanadite, (Pb5(VO4)3Cl), and gave a sample of his new discovery to a traveller, who then sent it to the French Institute in Paris, along with a letter explaining his discovery. The letter was lost on route and the French Institute only received the sample, which was then analysed. Upon analysis, the French Institute informed Del Rio that all he had done was rediscover chromium, as the properties of this new metal were very similar.
The second time vanadium was discovered was 30 years later, in 1831, by the Swedish chemist Nil Gabriel Selfstrom. Selfstrom separated it from a sample of cast iron and named it vanadium after the Scandinavian goddess of beauty, Vanadis (due to the range of colours produced by its salts).
The first reasonably pure sample of vanadium was produced by the English Chemist Henry Roscoe in Manchester, in 1869. He showed that previous samples of the metal must have been vanadium nitride. Even his sample was not completely pure, as it contained about 4% of impurities. A purity of 99.99% was not achieved until the 1920’s.
Vanadium production is mostly as a by-product or from recycling, with primary vanadium production accounting for just 20% of total production. Approximately 50% is recovered from steel-making slag; the rest is from oil and coal residues, spent catalysts and less than 5% as a by-product of uranium (U) production. China is the biggest producer at 38%, South Africa 27%, Russia 19%, USA 10% and other nations 6% (2008). The world production of vanadium ores is annually approximately 50,000mt, while the production figures for vanadium was about 110,000mt in 2008. The vanadium metal is extracted from red/brown oxide by heating calcium in a pressure vessel. Carbon cannot be used as a heating agent, due to how it reacts with the metal.
Added between 0.1% and 3% to steel, vanadium acts to strengthen it, make it rust-proof, to improve fatigue resistance, shock-resistance and vibration resistance, all vital qualities when used for springs, tools, jet-engines and armour plating. In steel making, vanadium pentoxide flakes are used to make ferro-vanadium 50 or 80 (FeV), the form in which vanadium is actually added to the steel (1.5mt of vanadium pentoxide (V2O5) is needed to produce 1mt of FeV80). For these reasons, worldwide vanadium consumption closely mirrors, and is thus dependent on, worldwide steel production, comprising over 50% of the vanadium produced, which is ultimately recovered from the process. In 2008, there was parity between the production and consumption of vanadium.
In the chemicals industry vanadium compounds are mostly used as catalysts (the largest end-use of vanadium within the chemicals industry, for the oxidisation of sulphur dioxide to trioxide and within polymer production), specialist glass (gives blue and green tint), enamels, printing inks (due to the range of colours produced by its salts), rechargeable batteries and ceramics (gives a golden colour). To a degree, vanadium can be substituted by niobium (Nb), molybdenum (Mo), manganese (Mn) and titanium (Ti) within the steel industry, but not in master and super-alloys. Finally, vanadium’s other application is in nuclear reactors, as it has low-neutron absorbing abilities and does not deform by ‘creeping’ under high temperatures.