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Information on tungsten: sources, properties and uses

Still an Element of Lighting

Since the dawn of the 20th century, tungsten metal has been a synonym for the incandescent bulb filament, and the symbol of the bulb has become iconic for sudden inspiration.  However, after more than 100 years of use in the different fields of lighting, tungsten filament bulbs have been, and are currently being, replaced by more energy efficient solutions; starting with fluorescent tubes in the late sixties, and finally by compact fluorescent lamps in the middle of the eighties.  Only domestic lighting is still a stronghold of filament lamps, simply because of their low initial cost and convenience.

Replacement of filament lamps by discharge lamps (CFL, fluorescent, HP mercury vapour, metal halide, LP-sodium or HP sodium, short-arc) has not at all lowered tungsten consumption in the field of lighting, because all these lamps contain tungsten in a certain form: either as filament, or as electrode material (coiled filament, coiled-coil, triple coil, rod-like or massive) in the form of tungsten, porous tungsten, emitter-coated tungsten or thoriated tungsten.  In particular High Intensity Discharge (HID) lamps have increased tungsten consumption significantly.

Climate Change as a Motor of Innovation

Current discussions on modern lighting and global warming and the subsequent product replacements will have no negative effect on tungsten demand in the near future, as much the same amount of tungsten will be used in an old filament bulb and a modern CFL lamp.  A negative tendency might be expected in the long term as the lifespan of such new lamps is significantly higher (up to 15 times!). However, more lamps than ever will be necessary (as more light will be produced), and even the number of filament bulbs might still slightly increase in the next few years (and then come down because of the phasing out of energy-guzzling devices).

In addition, tungsten is increasingly finding applications in areas where high luminous fluxes are needed for the various uses (photo lithography; semi-conductor technology; IMAX projection) or in the form of low-pressure cold cathode discharge lamps (CCFL) for scanners, flat screens, laptops, or television.

Electrode weights are in the order of mg (CFL: 10-20 mg) or several g (HID lamps) but can go up to kg in high performance short-arc lamps for cinema projection (up to 15kW).

Lower demand in the long term has to be expected from the development of electrode-free discharge lamps (induction lamps) and the further development of LED devices which are bringing about a revolution in the lighting market. 

© 2011 International Tungsten Industry Association
Copyright image courtesy of Osram