Why Are Rare Earth Metals So Important?
Dr. Alex King, director of the Critical Materials Institute at the U.S. Department of Energy's Ames Lab talks about recycling and alternatives for rare earth metals.
"I hate to say this because I’m a scientist, but rare earths are magic. They have very, very unusual magnetic properties, and occupy a unique niche in terms of light emissions. The best magnets in the world – the strongest, lightest magnets – are made out of neodymium, iron, and boron. The magnets that are used in small loudspeakers like ear buds, for example, have neodymium, making them very powerful and very light. Neodymium-iron-boron is also used in the electric motors you find in cars, such as the motors that drive your windows up and down and motors that adjust your rear-view mirrors. All sorts of other motors in a car use neodymium iron boron magnets. Because they produce so much magnetic force with so little weight, that helps make the cars more efficient.
"On the other end of things, in the lighting area, if you’re working in an office with fluorescent lights or if you have compact fluorescents at home, the light that’s produced comes from a rather complex phosphor. The color of the light is tuned carefully to make warm light colors, as opposed to the rather ghastly greens that early fluorescent lights had. Red and blue come from europium, and green comes from terbium.
"And if you use a computer – and I'm sure you do – the red, green, and blue on your computer screen and your smartphone all come from the same elements. Europium has the unique ability to emit high intensity red light. Terbium is pretty unique in emitting green light. Everything we use with high efficiency light, even LEDs, all use the same elements to produce the reds and the greens.
"In addition to everyday items like screens and lights, some of the same rare earth materials are used in defense systems. There is not any defense system in the entire U.S. military that doesn’t have some rare earth in it."
Dependence on Foreign Rare Earths
"What’s happened lately is that the demand for rare earths around the world has started to outstrip supply, and the supply has become localized in China. Until very recently, China was producing 97% of the entire world’s supply of rare earths. Compounding the problem, China has its own growing demand, because it has its own growing consumer base. They also want to supply finished products to the rest of the world, so they've been restricting exports. That's created a real pinch in the balance between supply and demand."
Solutions
"We're taking three primary approaches to increasing the supply of rare earth metals. One is producing more domestically, the second is trying to invent materials that perform the same but don’t require the rare earths. And the third is using what we have more efficiently by wasting less in manufacturing, recycling more, and designing products more carefully to use less.
"In regards to recycling, I think the answer there is dependent of which particular rare earth you’re talking about. For example, the market for neodymium is changing. I mentioned it is used primarily in small magnets. I think the biggest piece of neodymium iron boron magnet that anybody saw until very recently was in the hard disk drive in a computer, and it was three or four grams. But now we’re starting to see things like drive motors for electric cars. Those have about a kilogram of neodymium-iron-boron. Wind turbines can have up 700 pounds of neodymium or two tons of neodymium-iron-boron magnets. We’re talking about going from technologies that use these things in very small quantities to technologies that use very, very large quantities. The short answer is that if we recycled all the ear buds in all the landfills in the world, we wouldn’t supply enough to meet what we hope will be the demand for electric vehicles and wind turbines. Mining is the long term answer for those materials.
"The answer is a little more complicated when we talk about phosphors, because the demand for phosphors – the rare earths in lighting and iPhone screens – may flatten in the next ten to fifteen year time frame. I think that fluorescent lamps will be replaced eventually by LED lamps, which you're already starting to see. When you go to the hardware store these days, you don’t see that many old fashioned incandescent light bulbs. You see a lot of compact fluorescents, and you’re even beginning to see LEDs competing with CFLs. They also use rare earth phosphors to tune the color of the light, but they use much less than is used in fluorescent and compact fluorescent lamps. I think the best solution for those rare earths is recycling, and this is a field Veolia is already active in."
Recycling Challenges
"Recycling rare earths from fluorescent bulbs is difficult, but compared to cell phones it's relatively easy. Cell phones are very difficult to recycle, because you’re actually looking at a device that contains sixty-five elements from the periodic table, compared to a fluorescent lamp where you’ve got maybe six or eight elements. Recycling something out of a mixture of six or eight elements is manageable, but sixty-five elements? That’s worse than digging rock out of the ground. One way you can make cell phones and computers easier to recycle is by designing the components so that they can be easily separated from each other. If you had an old cell phone from a few years ago you know the battery was easily replaceable, and you could remove the battery from the phone. Newer phones require the phone to be disassembled.
"Designing electronics so that they easily separate into the basic components, so you can get the battery out, the central processing unit, which is basically silicon, and the circuit board, which contains most of the precious metals, is one solution. Designing for recycling is something that we are interested in promoting. We're trying to persuade manufacturers to label products with a barcodes stating what materials the product contains. By adding that barcode, it could be sorted in a recycling stream.
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