Seattle - SR-99 near the Washington State Ferry Terminal

Tungsten – W – Who says heavy metal is boring?

Tungsten (W – Atomic number 74) is one of the densest metals, 1.7 times heavier than lead, and up there with gold and uranium.  It has a very high melting point – 3413 °C – and is also alloyed with other metals to strengthen them.

Drill bit
Drill bit

These properties account for the major uses of tungsten, one which is dying out – the use as a filament in incandescent lamps (compact fluorescent and LED are much more efficient means of creating more light and less heat) and the other of creating very hard materials that withstand high temperatures.  Arc-welding and heating elements in furnaces, as well as drill tips are an example of these uses.  Tungsten Carbides (W2C and WC) are formed when powdered tungsten is heated with carbon – and these carbides are very hard – used for machining tools as well as armaments.

Torch light bulb
Torch light bulb

Tungsten is also known as Wolfram is some languages (where the W comes from…).  The ores it is produced from are wolframite and scheelite.  Tungsten comes from the Swedish tung sten meaning heavy stone.

Like Tin, Tungsten is known as a conflict mineral due to the unethical mining practices that have been observed in the Democratic Republic of the Congo.  Industrial users of Tungsten need to be able to trace the supply chain to source.

Talking of sources, the 4th richest deposits of Tungsten can be found in the UK, in Devon, and the increasing world price has seen the recent work to re-open the mines, at Hemerdon, Dartmoor.  This work will also see Tin mining return to Devon as this metal is also found in the same deposits.

Drill bit
Drill bit

Tungsten’s discovery is credited to Juan and Fausto Elhuyar who isolated the metal in 1783, although earlier work on identifying a new metal from the minerals goes to Peter Woulfe and Wilhelm Scheele.  Even earlier (more than 350 years ago) a Tungsten based pigment had been used in China for a unique peach colour in porcelain.

Other uses of Tungsten are for ballast due to its density – both for ocean and space going ships, as well as racing cars -and it is also used in Jewelery and making darts (why isn’t darts an Olympic sport yet?)

Tungsten is also the heaviest element known to have a biological function (next heaviest is Iodine – 53) – and is found in some bacteria in an enzyme that typically reduces carboxylic acids to aldehydes.  Tungsten is the only element ever to have been the subject of patent proceedings – and General Electric’s 1928 attempt was rejected – and the 1913  U.S. Patent1,082,933 overturned.

I struggled to find good photographic uses of Tungsten, (Industrial X-ray equipment maybe – or ballast to keep tripods steady) so finishing with a picture that shows Seattle’s Highway SR-99 – which is being replaced by a tunnel – being dug by ‘Bertha‘ whose teeth may use Tungsten.  The teeth on this largest ever tunnel boring machine are interchangeable depending on the rock/soil mix being tunneled – perhaps if ‘Bertha’ had her Tungsten Carbine teeth in that steel pipe would not have stopped her…

Seattle - SR-99 near the Washington State Ferry Terminal
Seattle – SR-99 near the Washington State Ferry Terminal

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