Europium: Savior of the TV Generation
Sir William Crookes, a 19th century British chemist, once wrote that, "rare earth elements perplex us in our researches, baffle us in our speculations and haunt us in our very dreams." These weren't easy elements to isolate or to understand, and so there was a very long lag time between the discovery of the rare earths, and the discovery of practical uses for them.
It didn't help that individual rare earth elements don't occur by their lonesome—they travel in packs. To get one, you have to mine all of them. At first, industry didn't even bother to separate out individual rare earths, instead using them in a blended alloy called mischmetal. This provided the first commercial applications, says Karl Gschneidner, senior metallurgist at the Department of Energy's Ames Laboratory. In 1891, mischmetal became an ingredient in lamp mantles—devices that were hung above open flames, where they burned and produced a bright, white light you could see and work by.
Europium was the first isolated, high purity rare earth element to enter the public marketplace, in 1967, as a source of the color red in TV sets. There had been color TV before europium, but the color quality was weak. The sets relied on phosphors—substances that glow when struck with struck with electrons or other energized particles—to get their red, green and blue colors, and the early red phosphors couldn't produce a very bright color. Europium phosphors made the picture pop.
At the time, rare earth mining wasn't even a twinkle in China's eye. Up until the 1990s, most rare earth elements came from the United States, especially Mountain Pass, a mine in California near Los Angeles, which supplied most of the late 1960s europium demand. By 2003, Mountain Pass had closed and no rare earths were coming out of the United States at all. The problem, though, isn't supply. The U.S. still has plenty of rare earth elements left to mine—in Mountain Pass and elsewhere. Instead, those mines were simply driven out of business, undercut on price by Chinese companies that had lower labor costs, and also benefited from the fact that they were mining rare earth elements as a byproduct of profitable iron mining.
Today, europium is still used as a phosphor, but as cathode ray tube TVs go the way of the dodo, it's more likely to turn up in white LED-based lights, which could someday be an energy efficient replacement for both incandescent and compact fluorescent bulbs. With this technology, white light is produced by mixing various colored LEDs and europium red happens to be an ingredient in turning out a high-quality, attractive shade of white.