In 1779 Peter Woulfe examined the mineral commonly know today as wolframite and concluded in his examination there to be a new substance within it. It was not until 1783 that the de Elhuyar brothers found an acid in wolframite (tungstic acid) that was identical to another acid found in the mineral known today as scheelite. In that same year they succeeded to obtain the element by reduction of this acid with charcoal.
Tungsten occurs in wolframite ((Fe, Mn)WO4), scheelite (CaWO4), huebnerite (MnWO4) and ferberite (FeWO4). The metal is obtained commercially by the reduction of tungsten oxide with hydrogen or carbon. Tungsten, with a chemical symbol of W is also known as wolfram, and this name originated from medieval German smelters who found that tin ores containng tungsten had a much lower yield. It was said that the tungsten devoured the tin 'like a wolf'.
Tungsten has the highest melting point of all elements except carbon - sources in scientific literature vary between 3387°C and 3422°C. It also has also excellent high temperature mechanical properties and the lowest expansion coefficient of all metals. A temperature of about 5700°C is needed to bring tungsten to boil - which corresponds approximately to the temperature of the sun’s surface. With a density of 19.25 g/cm3, tungsten is also among the heaviest metals. Its electrical conductivity at 0°C is about 28% of that of silver which itself has the highest conductivity of all metals.
Pure tungsten is a steel-grey to tin-white metal. The pure metal has the ability to be cut with a hacksaw, may be forged, spun, drawn, and extruded. However, the impure metal is brittle and can be worked with some difficulty. Natural tungsten has five stable isotopes, with a further twenty-one other unstable isotopes are recognised.
Tungsten as a Strategic Metal
Tungsten has been identified by British Geological Surveys (BGS) as a Critical Mineral. Details can be found at http://www.bgs.ac.uk/mineralsuk/statistics/riskList.html
BGS has put together a tungsten fact sheet that can be referred to at http://www.strategic-metal.com/index.php/products/productslist/W/8
This lists Hemerdon as the 4th largest tungsten resource in the world. DEFRA has put together an RPPSD which can be found at DEFRA- Resource Projection Action Plan