Tungsten element mainly exists tungsten ore, scheelite and ferberite. China produces about 75% of tungsten ore and 25% of tungsten ore is exploited by Austria, Bolivia, Portugal and Russia.
As for tungsten element applications, due to tungsten has good stability in high temperature, so tungsten element is widely used in high temperature. Such as tungsten is able to be used in tungsten filament, cathode-ray tube, vacuum tube, heating element, and nozzle of the rocket engine. Tungsten element also has high melting point. So tungsten element can be used in aerospace and high temperature resistant materials, such as electrical equipment, application of welding, especially in inert gas arc welding.
Because of the electric conductivity and relatively chemical inertness, tungsten element also can be used in electrode, electronic emitter, electron microscope and others. In the electronic industry, tungsten is able to be applied as interconnect material, silicon dioxide insulating material and transistor of integrated semiconductor. Tungsten metal film (or molybdenum coating wire) replace silicon which is the traditional material used in electronic equipment.
Due to the hardness and density of tungsten, tungsten element is also used to produce heavy metal alloy. Like, tungsten element can be used to make high-speed steel.
Tungsten compounds can be used as catalyst, inorganic pigments (such as tungsten oxide), and high temperature lubricating oil (disulphide). Tungsten carbide (WC) is used to make abrasive material, knife tool and bit wing, circular saw, milling and turning tools. About 60% of tungsten carbide is used in metal processing, wood processing, mining, petroleum and building industry. Tungsten oxides can also be used in ceramic glazes and calcium / magnesium tungstate and are widely used in fluorescent lamp, tungsten halogen lamp. Crystal tungstates are used in nuclear physics, nuclear medicine scintillation detector. Others containing tungsten salt can be used in the chemical industry and tanning industry.
