Rare earths in the lighting industry

A few weeks ago I wrote, that one of the most important changes, has taken place in the field of rare earth elements, the lighting market concerns. Fluorescent tubes work by bouncing electrons on atoms of a refined gas in a glass tube and excite the atoms, then emit UV photons. These photons hit on fluorescent molecules, which convert the high-energy UV light into visible light,.

For those of you, who did not know it: Sitting under a bare fluorescent light, compact or not, means great confidence in the quality control of the manufacturer to have. Only if the phosphor coating is extremely evenly and completely, escapes no bad UV light, the skin can cause cancer. Keep the lamps behind plastic or glass, to ensure, that does not happen.

For preparing fluorescent light, a glass tube is required, and a liquid fluorescent particle suspension, in order to coat the inside of the tube. Once the liquid has evaporated, the glass tube is heated to the point at which the glass will soften and adhere to the phosphor particles in the tube. Then the tube is filled with gas and sealed.

Heutzutage werden für die besten Leuchtstoffe Rare earth, such as yttrium and cerium used as a carrier and terbium and europium as a dopant and light emitter. Someone realized that a while ago, while the phosphor particles is smaller than 10 μm sind, only the surface and the area directly below, interact with the UV photons.

As rare earths were more expensive and were more difficult to get, decided several companies, Produce phosphor particles, by establishing free carrier particles without rare earths and coated carrier particles with fluorescent material. The result in terms of lighting was the same. The cost was, due to the lower use of high-priced rare earths, equal to less.

The general view is, that we are in transition from fluorescent lamps to LEDs. A reader asked, how these changes would affect the demand of rare earths. While LEDs contain less phosphorus material, the demand for rare earths could rise, because much more LEDs are required.

I think, concerning whether the question. Number compared to needed material requirements per unit is easy to answer. A typical LED has a luminous efficacy of about 110 lm / W, and the devices are typically 1 W performance and contain a ca. 1 gallium mm2 chip with a phosphor coating of about 4 mg/ mm2 (after a patent by Nichia). Say the same specifications for T8 fluorescent tube, that the light yield about 90 lm / W is, but the power consumption in a 900mm pipe about 30 W ist, with an inner surface of 456 cm2 (according to a GE patent) and about 2,5 mg/cm2 phosphor coatings. That tells us, that a single tube T8 of 900 mm length about 2700 Generated lumens and about 1.140 mg Phosphor enthält. To the same 2.700 To produce lumens of light, evtl. even of better quality, are approximately 25 LEDs with a total 100 mg Phosphor notwendig.

It seems, that the phosphors used almost exactly contain the same amounts of rare earths, since the mechanisms for producing the visible light are basically the same for an LED and a fluorescent lamp.

The required amount of phosphorus to rare earths and thus generated per amount of light is decided lower than that for phosphor for LED. Note, that we do not discuss here the power consumption in lighting. The LED lights use less power, but they need much less rare earths, to do so.

All the above figures were generated prior to the latest development of phosphor-coated carrier particles. The amount of phosphorus for efficient lighting is now fallen dramatically and will continue to fall, da LEDs, Replaced phosphors and light bulbs.

But there is hope. According to GE, in 2013, make LED lights z.Z. the only 18% of the market and bulbs are still an important player. However, GE also says, that the market share of LEDs is expected to 70% in 2020, mainly at the expense of light bulbs, will increase.

Most of this increase comes by laws in the U.S., as well as restrictions in China, the reduced energy consumption for lighting in government- demands and office buildings. Apart from additional technology developments to the goal of reducing phosphorus, might provide to LED lighting the rare earths supplier something to cheer the conversion.

Those: http://investorintel.com/rare-earth-intel/lighting-way-rare-earths-lighting/





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