Introduction to Tungsten

Name
Wolfram in China(see map)
Our Tungsten Production Process
Physical Properties

Chemical Properties

[Tungstates]     [Tungsten,(w)]     [Tungsten]     [Tungstic acid]     [Tungsten oxides]  [Tungsten blue]     [Tungsten carbides]     [Tungsten alloys]     [Tungsten bronzes]  [Tungsten carbonyl, W(CO)6]     [Tungsten halides]     [Tungsten, organic derivatives]

History
Occurence

Isotopes

Uses

Material safty Data Sheet(MSDS)


Name:  

English: Tungsten
Germany: Tungstein
Chinese:
(to be read / wu:/)
Swedish: tung sten or heavy stone
Alternative name: wolframite  

Physical Properties:

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Atomic Number: 74 Atomic Symbol: W
Atomic Weight: 183.5 Electron Configuration: 2-8-18-32-12-2
Shells: 2,8,18,32,12,2 Filling Orbital: 5d4
Melting Point: 3410oC Boiling Point: 5927oC
Description: Hard, silver-white metal.
Uses: Used widely in the electronics industry. Made into filaments for vacuum tubes and electric lights. Also as contact points in cars. Combined with calcium or magnesium it makes phosphors.

The metal is obtained commercially be recucing tungsten oxide with hydrogen or carbon. Pure tungsten is a stelel-gray to tin-white metal. Very pure tungsten can be cut with a hacksaw, and can be forged, spun, drawn, and extruded. The impure metal is brittle and can be worked only with difficulty. Tungsten has the highest melting point of all metals, and at temperatures over 1650C has the highest tensile strength. The metal oxidizes in air and must be protected at elevated temperatures.It has excellent corrosion resistance and is attacked only slightly by most mineral acids.

Chemical Properties:

Tungstates Formed by dissolving WO3 in NaOH solution and subsequently by cation exchange. The normal tungstates. e.g.Na2WO4,2H2O, contain tetrahedral WO42-ions. Most metal salts other than alkali metal salts are insoluble. Acidification of a solution of WO42-ions gives polymeric anions-iso-polytungstates-containing WO6 octahedra joined corner to corner to corner or edge to edge; [HW6O21]5- ,[H2W12O42]10- and[W12O39]6- are well-established. If the acidification is carried out in the presence of another oxyanion, heteropolytungstates in which MO6 or MO4 groups (M=heteroatom) are incorporated into the polyanion are formed. E.g.[FeW12O4]5- and [PW12O4]3- .It seems unlikely that free tungstic acids of any of these forms are sable. Further acidification of isopolytungstates gives WO3,2H2O, Heteropolytungstates are used to form Wcontaining catalysts by heating.

Tungsten,(w) The main ore of tungsten is wolframite (Fe,Mn)WO4; scheelite (CaWO4) and solzite (PbWO4) are also important. The concentrated ores are fused with NaOH and, after water extraction, WO3 is precipitated with acid and reduced to the metal with H2. The metal is bcc. The fuse metal is lustrous silver-white and is only attacked slowly even by HNO3-HF. Dssoleds in KNO3-NaOH or Na2O2, attacked by O2 at red-heat. The metal isused extensively in steel alloys, in electric lamp and heating filaments and in electric contaces. Tungsten carbides are very hard and are used in cutting tools. World production WO31981 52000 tonnes.

Tungsten is a typiacl element of transition element Group VI and shows oxidation states from +6 to-2 and, particularly in its oxides, forms many non-stoicheiometric compounds. There is little aqueous chemistry except that of complex oxy-anions and some complex halides. The hexahalides are moleular but lower halides are polymeric and the lowest halides show extensive W-W bonding (more than Mo). Carbonyl and phos-phine derivatives are typical low oxidation state compounds. Complexes are formed, particularly by O-and S-ligands in higher oxidation states and by P-ligands in low oxidation states. Complex cyanides are well established.

Tungstic acid See tungstates.

Tungsten oxides Yellow WO3 is the final product from heating tungsten or other tungsten oxides in excess oxygen. It is used in yellow glazes for ceramics. Brown WO2 (WO3+H2) and many intermediate phases containing shear structures* (e.g.W18O49) are formed by reduction of WO3. Mixed metal oxides are formed by fusing WO3 with other metal oxides.

Tungsten blue Partially reduced WO3 or tungstates.

Tungsten carbides W2C and WC are obtained by heating W powder with C. Both compounds are extremely hard and are used for making cutting tools and dies. Ternary carbides are also used in cutting tools and other metallic carbides, borides, silicides or nitrides are added to improve the mechanical properties of the mixture.

Tungsten alloys The most impotant alloys are the tungsten steels whichcontain up to 18% of tungsten. Stellite, an extremely hard alloy of W with Cr and Cu, is used for high-speed cutting tools. Electric contacts for switch-gear are made from Cu and Ag-W alloys.

Tungsten bronzes Coloured compounds MnWO3 (M= unipositive metal 0<n<1) prepared by reducing tungstates with, e.g., Na. The compounds contain Wv1and Wv

Tungsten carbonyl, W(CO)6 Bery similar to molybdenum carbonyl* but less readily substituted.

Tungsten halides The known fluorides are colorless WF6(W+F2), b.p.17íŠ,mixed tungsten(VI) chloride fluorides (e.g. WF5Cl) and derivatives of WF6 (e.g. WF5OMe), tetrameric WF5 (W+WF6) and WF4 (heat on WF5). Complex fluorides of W(VI) and W(V) contain ions such as [WF7]-and [WF6]-. The knowm chlorides are WCl6(W+Cl2) an olefine metathesis reagent, green WCl5(W+Cl2), involatile WCl4(WCl6+Al), WCl3 and WCl2(both WCl6+H2). WCl3 and WCl2 both contain metal-clusters [W6Cl12]Cl6 and [W6Cl8]Cl4 respectively. Complex chlorides containing [WCl6]- ,[WCl6]2-,[W2Cl9]3- are known ([W2Cl9]3- contains three bridging Cl and a W-W bond), All of the halides form extensive ranges of complexes with various ligands. Hydrolysis of the higher oxidation state fluorides and chlorides gives oxide halides and these compounds may also be prepared directly from oxides and halogenating agents. WOF4, [WOF5]-, [WOF4]2-, [WO2F3]3-, WOCl4, WO2Cl2,WOCl3 and [WOCl5]2- are known and their chemistry is similar to that of the halides. Tungsten bromides, WBr6, WBr4, WBr3, WBr2 and iodides WI4, WI3 and WI2 are similar to the chlorides.

Tungsten, organic derivatives Generally similar to the molybdenum derivatives but higher oxidation state alkyls, e.g. WMe6 (WCl6+LiMe) are known.

History:

In 1779 Peter Woulfe examined the mineral now known as wolframite and concluded it must contain a new substance. Scheele, in 1781, found that a new acid could be made from tungsten (a name first applied about 1758 to a mineral now known as scheelite). Scheele and Berman suggested the possibility of obtaining a new metal by reducing this acid. The de Elhuyar brothers found in acid in wolframite in 1783 that was identical to the acid of tungsten (tungstic acid) of Scheele, and in that year they succeeded in obtaining the element by reduction of this acid with charcoal. Tungsten occurs in wolframite, scheelite, huebnertie, and ferberite. Important deposits of tungsten occur in California, Colorado, South Korea, bolivia, Russia, and Portugal. China is reported to have about 75% of the world's tungsten resources. Natural tungsten contains five stable isotopes. Twenty one other unstable isotopes are recognized. The metal is obtained commercially be recucing tungsten oxide with hydrogen or carbon. Pure tungsten is a stelel-gray to tin-white metal. Very pure tungsten can be cut with a hacksaw, and can be forged, spun, drawn, and extruded. The impure metal is brittle and can be worked only with difficulty. Tungsten has the highest melting point of all metals, and at temperatures over 1650C has the highest tensile strength. The metal oxidizes in air and must be protected at elevated temperatures. It has excellent corrosion resistance and is attacked only slightly by most mineral acids. The thermal expansion is about the same as borosilicate glass, which makes the metal useful for glass-to-metal seals. tungsten and its alloys are used extensively for filaments for electric lamps, electron and television tubes, and for metal evaporation work; for electrical contact points for automobile distributors; X-ray targets; windings and heating elements for electrical furnaces; and for numerous spacecraft and high-temperature applications. High-speed tool steels, Hastelloy(R), Stellite(R), and many other alloys contain tungsten. Tungsten carbide is of great importance to the metal-working, mining, and petroleum industries. Calcium and magnesium tungstates are widely used in fluorescent lighting; other salts of tungsten are used in the chemical and tanning industries. Tungsten disulfide is a dry, high-temperature lubricant, stable to 500C. Tungsten bronzes and other tungsten compounds are used in paints. Tungsten powder (99.9%) costs about $50/lb.

Occurence:

Tungsten occurs in wolframite, scheelite, huebnertie, and ferberite. Important deposits of tungsten occur in USA(California and Colorado), South Korea, bolivia, Russia, and Portugal. China(Jiangxi and Hunan Province) is reported to have about 75% of the world's tungsten resources.

Isotopes:

Natural tungsten contains five stable isotopes. Twenty one other unstable isotopes are recognized.

Uses:

The thermal expansion is about the same as borosilicate glass, which makes the metal useful for glass-to-metal seals. Tungsten and its alloys are used extensively for filaments for electric lamps, electron and television tubes, and for metal evaporation work; for electrical contact points for automobile distributors; X-ray targets; windings and heating elements for electrical furnaces; and for numerous spacecraft and high-temperature applications. High-speed tool steels, and many other alloys contain tungsten.Tungsten carbide is of great importance to the metal-working, mining, and petroleum industries. Calcium and magnesium tungstates are widely used in fluorescent lighting; other salts of tungsten are used in the chemical and tanning industries.Tungsten disulfide is a dry, high-temperature lubricant, stable to 500C. Tungsten bronzes and other tungsten compounds are used in paints.

Material Safety Data Sheet (MSDS)

We are pleased to offer our MSDS for our Tungsten materials such as Ammonium Paratungstate, Ammonium Metatungstate, Tungstic Aicd, Blue Tungsten Oxide,Tungsten Oxide, Tungsten Powder, etc. So, if you are interested in getting this information together with the commodity when we delivery it to you, please let us know when you place you order.