Symbol: | W |
Melting point: | 3,422'C |
Electron configuration: | [Xe]4f145d46s2 |
Atomic number: | 74 |
Atomic mass: | 183.84 ± 0.01 u |
Ore | Common Name | Formula |
---|---|---|
Oxide | Tungstite or Tungstic Ochre | WO3 |
Tungstates | Wolframite | [Fe,Mn]WO4 |
Hubnerite | MnWO4 | |
Ferberite | FeWO4 | |
Scheelite | CaWO4 |
Wolframite ore is crushed and roasted. The roasted ore is reduced with coal in a rotary kiln .The reduced ore is melted in an electric arc furnace to produce ferrotungsten. Scheelite ore is roasted and reduced .The reduced ore is melted in an electric arc furnace. The oxygen is blown into the metal bath. Calcium joins the slag and separated. The tungsten metal is further refined and cast into metal castings. If impurities of tin or other metals are found, these are separated by electrolytic refining process.
Tungsten is strong carbide forming element .When added to steel it maintains fine grain size of steel .It also increases the wear and abrasion resistance character of steel. It also provides resistance to heat and corrosion .It is used in tool steels, heat resisting steels and high speed steels. Tungsten is also used in micro-alloyed steels. Tungsten is alloyed with titanium. It increases the melting point. These alloys have potentials for high temperature application. These alloys are used in aerospace industries and medical instrument industries.