Thursday, April 26, 2012

Tungsten 74

Electron shell 74 Tungsten

God has created the world so that also tungsten is made in those majestic supernova explosions that - according to our current understanding - generate all the heavier elements in the universe.

Like uranium and throium, also tungsten is a modern era discovery almost unknown to the ancients. It is used in many industries because of its resistance to heat, corrosion and extreme hardness, especially when combined with carbon. It is one of the modern things that humanity has discovered hidden in the soils and rocks of mother Earth and learned to take advantage of.

Tungsten filament lamp

Who has not heard of tungsten lights? Tungsten filaments do not melt under three thousand Celsius (some of us still remember those old times electric lamp bulps going off in the night with a crack just when most needed...)
Faceted tungsten carbide ring

Tungsten rings are very beautiful and durable unless you hit them with a hammer (don't). 

There is natural tungsten on planet Earth in chemical compounds. It is extremely hard and has one of the highest melting points of any metals at 3,422 °C  (6,192 °F).

But really, what is it good for?

Tungsten, also known as wolfram, is a chemical element with the chemical symbol W and atomic number 74. The word tungsten comes from the Nordic tung sten directly translatable to heavy stone.

A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as a metal in 1783. Its important ores include wolframite and scheelite.

The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the non-alloyed metals and the second highest of all the elements after carbon.

Also remarkable is its high density of 19.3 times that of water, comparable to that of uranium and gold, and much higher (about 1.7 times) than that of lead.

Tungsten with minor amounts of impurities is often brittle and hard, making it difficult to work. However, very pure tungsten, though still hard, is more ductile, and can be cut with a hard-steel hacksaw.

Minerals and mining
Tungsten is found in the minerals
  • wolframite (iron-manganese tungstate, (Fe,Mn)WO4), 
  • scheelite (calcium tungstate, (CaWO4), 
  • ferberite (FeWO4) 
  • hübnerite (MnWO4). 
China produced 51,000 tonnes of tungsten concentrate in 2009, which was 83% of the world output. In the prelude to WWII China's production of tungsten played a role as China could use this leverage to demand material assistance from the US government.

Most of the remaining production originated from Russia (2,500 t), Canada (1,964 t), Bolivia (1,023 t), Austria (900 t), Portugal (900 t), Thailand (600 t), Brazil (500 t), Peru (500 t) and Rwanda (500 t).

Tungsten is also considered to be a conflict mineral due to the unethical mining practices observed in the Democratic Republic of the Congo. 

Tungsten in living beings
Tungsten, at atomic number 74, is the heaviest element known to be biologically functional, with the next heaviest being iodine (Z = 53). Although not in eukaryotes, tungsten is used by some bacteria.

Found in some bacteria?

So what?

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