Applications
Tungsten is used in filaments in incandescent light bulbs, it is also used in
electric contacts and arc-welding electrodes. Tungsten is used in alloys, such
as steel, to which it imparts great strength. Cement carbide is the most
important use for Tungsten: its main component is Tungsten carbide (WC). It has
the strength to our cast Iron and it makes excellent cutting tools for the
machining of steel. X-ray tubes for medical use have a Tungsten emitter coil and
the screen used to view X-rays rely on Calcium and Magnesiumtungstate phosphors
to convert X-rays into blue visible light. Tungsten is also used in microchip
tecnology and liquid crystals displays.
Tungsten in the environment
Very little Tungsten has been detetced in the dew soils that have been analysed
for it, although around an ore-processin plant in Russia levels as high as 2000
ppm were found. The concentration of the element in natural waters is very low.
There are several minerals of Tungsten, the most important are scheelite and
wolframite. The main mining area is China, which today accounts for more than
two-thirds of the world's supply. Other places with active Tungsten mines are
Russia, Austria, Bolivia, Peru and Portugal. World production is around 40.000
tonnes per year and reserves are estimated to be around 5 million tonnes.
Tungsten is also recycled and it meets 30% of demand.
Health effects of Tungsten
Tungsten has been shown to act by antagonizing the action of the essential trace
element, Molybdenum. Long industrial experience has indicated no pneumoconiosis
to develop among workers exposed solely to W or its insoluble compounds (at air
concentrations of the order of 5 mg/m3).
Acute Health effects: Irritating to the skin and eyes on contact. Inhalation
will cause irritation to the lungs and mucus membrane. Irritation to the eyes
will cause watering and redness. Reddening, scaling, and itching are
characteristics of skin inflammation. Follow safe industrial hygiene practices
and always wear protective equipment when handling this compound.
Chronic Health effects: This product has no known chronic effects. Repeated or
prolong exposure to this compound is not known to aggravate medical conditions.
All Tungsten compounds should be regarded as highly toxic. The metal dust
presents a fire and explosion hazard.
Effects of Tungsten on the environment
Tungsten metal powder administered to animals has been shown in several studies
as not altogether inert. One study found that guinea pigs treated orally or
intravenously with Tungsten suffered from anorexia, colic, incoordination of
movement, trembling, dyspnea and weight loss. This product is not expected to be
hazardous for the environment. No specific ecotoxicity data is available for
this product.
