What is Tungsten ?
Tungsten (pronounced /tʌŋstən/), also known as wolfram (/wlfrəm/), is a chemical element with the chemical symbol W and atomic number 74. Tungsten is as known the heaviest materials except gold of the nature resources, for the density of tungsten is 19.25 g•cm−3(near r.t.). For the same reason, tungsten related products, alloys(Nickel-Copper-Ferro Binder), other elements doped(Al-doped, Th-doped, La-dope, Ce-dopd and K-doped) and carbides( carbonized tungsten powder with cobalt or Nickel binder) have the special ccharacteristics as pure tungsten, then it always named heavy stone.
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.
Tungsten is one of Nonferrous Metals, and also it is as molybdenum and rare earth which are Refractory Metals, in the modern industrial time, it is the most important Strategic Metals for IT industrial and military industrial.
What is the problem with tungsten? Tungsten dissolves readily in water and is mobile under some field conditions, challenging initial assumptions with regard to tungsten’s fate and transport characteristics. Other concerns include data (occupational, animal studies, cancer clusters) indicating adverse non-cancer and cancer health effects and risk outcomes.
How is tungsten used? Tungsten alloys are good conductors of electricity, and used primarily to increase the toughness and strength of steel. The most common tungsten product, cemented tungsten carbide, is used to make grinding wheels and cutting or forming tools. Tungsten powder is used as a lead replacement in bullets. However, firing of a tungsten/nylon bullet introduces tungsten and other projectile related metals into the environment.How does exposure to tungsten affect human health?
The toxicology of tungsten depends on the route of administration, the solubility of the constituent and the duration of exposure. Occupational exposure via the inhalation pathway has revealed elevated levels of pulmonary fibrosis (scarring of the lung tissue) and other effects including asthma and inflammation of the nose tissues. Research also suggests that the combination of tungsten and other substances can be linked to the development of lung cancer. Some animal data suggests that tungsten could cause adverse developmental and reproductive effects (including the kidneys as a target organ). Information from Nevada has drawn attention to tungsten’s potential toxicity as exhibited in the Fallon Nevada cancer cluster.
The tungsten directory site contains a lot of knowledge on tungsten products