Tungsten- W is the symbol for wolfram (tungsten), which is a chemical element in group VIB of the periodic table. Its atomic number is 74 and its density is 19.35 g/cm³. Its melting point and boiling point are respectively 3410.0 ℃ (3683.15 K, 6170.0 °F) and 5660.0 ℃ (5933.15 K, 10220.0 °F). Pure tungsten is a light gray or whitish metal, which is a solid at room temperature. Tungsten doesn't occur in its pure metallic state in nature, rather it exists in several ores, but only wolframite and scheelite are mined commercially. Of all metals in pure form, tungsten has the highest melting point, the highest tensile strength and the lowest vapor pressure. It has excellent corrosion resistance and the bulk metal resists attack by oxygen, acids and alkalis. Tungsten is widely used in the production of hard materials, alloys, filaments, electrodes, industrial catalysts, etc.
Of all metals in pure form, tungsten has the highest melting point, the highest tensile strength and the lowest vapor pressure.
- Tungsten: history and industry development
- The history of tungsten dates back to the 17th century. Miners in the Erz Mountains of Saxony found that the presence of certain ores disturbed the reduction of cassiterite (a tin mineral) and induced slagging....
- Tungsten: uses
- Cemented carbide, also called hard-metal, is the most important usage for tungsten, and its main component is tungsten carbide (WC) whose hardness is only slightly lower than diamond...
- Health effects of tungsten
- People can be exposed to low levels of tungsten by eating food, breathing air or drinking water that contains tungsten. They can also be exposed to tungsten by using consumer products containing tungsten...
- Classification of tungsten ores
- Tungsten does not occur naturally in its pure metallic state; rather, it is found in several ores, but only two kinds of tungsten-bearing mineral rocks, called wolframite and scheelite, are mined commercially...
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- Reference
- Tungsten Chemicals and their Applications by J. Christian, R.P. Singh Gaur, T. Wolfe and J. R. L. Trasorras--ITIA
- Tungsten--USGS
- The wolframite Mineral Series--Minerals.net
- The mineral scheelite--Galleries.com
- About tungsten: history, tungsten processing, primary uses, resources--ITIA
- Toxic Substances Portal – Tungsten--ATSDR
- Tungsten--lenntech
- Hazardous substance fact sheet: tungsten--New Jersey Department of Health and Senior Services
- Tungsten Applications--ITIA
- Metal Profile: Tungsten--About.com
- Tungsten (W) - Properties, Applications--Azom.com
- About ITIA--ITIA
- Tungsten supply – Where does the future lie? By David Merriman--Roskill
- Tasman Expands Critical Metal Portfolio with Acquisition of Tungsten Projects in Sweden--Yahoo.com
- American company agrees to buy Molyhill tungsten By Caddie Brain--ABC Rural