Symbol:W
Melting point:3,422'C
Electron configuration:[Xe]4f145d46s2
Atomic number:74
Atomic mass:183.84 0.01 u
OreCommon NameFormula
OxideTungstite or Tungstic Ochre WO3
TungstatesWolframite[Fe,Mn]WO4
HubneriteMnWO4
FerberiteFeWO4
ScheeliteCaWO4

Tungsten

Tungsten is a metal of grayish black in color. Tungsten is used as an alloy metal. Ferrotungsten is used as ferroalloys for production of special steels, tool steels and tungsten alloys. Tungsten alloy wires and filaments are used in electrical equipments. Tungsten salts are used in fire fighting programs. Wolframite and scheelite are two important ore minerals of tungsten. Wolframite is generally associated with tin ore cassiterite .Tin and tungsten are extracted and separated by chemical process .Tungsten ores are found as primary minerals associated with acid igneous rocks. The major producers of tungsten are China, Russia, Canada, South Korea, Australia, Bolivia, Portugal, Brazil, Austria, USA, and Myanmar.

Extraction of Tungsten

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.

Alloys of Tungsten

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.

instrument industries.