We use rare earth elements to magnetize the hard drives on our computers and make our cell phones vibrate. One particular rare earth element, Europium, produces red and blue phosphors; another, yttrium, produces green phosphors. All the colors we see on our TV’s, computers and smart phones are obtained from these primary colors, using these rare earth elements. Applications of rare earth elements abound including the magnets used for magnetic resonance imaging. A rare earth magnet can lift one hundred time its own weight.
In all, there are 17 rare earth elements. For the most part, these metals are heavy, being listed in order toward the bottom of the periodic table. It is not so much that they are rare as that the ores in which they are found have a low percentage yield. The world’s largest rare earth mine, in Mongolia, supplies more that 80 percent of the market worldwide. There are many other mines including the Mountain Pass Mine in California.
We expect any mine to have some negative environmental impact. The large open pits used to extract rare earth elements are no exception. Processing the ores with caustic chemicals extracts the desired elements but leaves waste pools containing radioactive thorium. Processing is also energy intensive, requiring up to one hundred kilowatt-hours of energy to obtain a single kilogram of product.
Rare earth magnets, typically neodymium-boron-iron, are also used in electric car motors and wind turbine generators. Therein lies a problem. Any plan to get to net-zero carbon emission by 2050 requires that most cars on the road be electric and that at least a quarter of our electricity be obtained from wind. We need to significantly increase the supply of these elements.
All of this suggests the urgent need to better recycle the rare earths elements. It is estimated that just recycling computer hard drives could supply 15 percent of the world’s current needs. Admittedly, recycling presents some problems. The manufactured products containing rare earth elements have been combined with other elements or compounds for added durability. Research is currently underway to improve the efficiency by which the rare earths can be separated from the products containing them.
The contamination of our oceans attest to the fact that we have not done a very good job recycling plastic. Here is another chance to get recycling right, perhaps with more dire consequences if we don’t.
Jim Peters for the Green Sanctuary Committee.