Pub 9 2021 Issue 1

Rare Earth Minerals I n 2020, the U.S. learned to value many things no one ever expected to lose: full shelves in the grocery store, going to sporting and cultural events, travel and social events. Zoom became a necessity for work, worship and catching up with friends. In short, the high-tech products that made social distancing bearable and kept the restau- rant industry afloat through online orders were something we took for granted in the same way we used to not-think about toilet paper. You know you don’t want to live without it, but you don’t think you’ll ever have to. High-tech products use rare earth elements. The most important application is probably their use in magnets for the coming onslaught of hybrid and electric vehicles. The magnets in these vehicles use neodymium (Nd), praseodymium (Pr), dysprosium (Dy) and terbium (Tb). Other applications include prod- ucts as diverse as the phone in your pocket, the hard drive in your computer or laptop, medical products, military defense systems and air pollution control. They are even used to make steel alloys. Rare earth metals are needed to make more than 200 products work, even if they only use small quantities. A battery may not look very impressive, but take it out, and how useful is the thing it is supposed to power? Certain rare earth alloys are extremely hard. They are essential for armored vehicles and projectiles that have been designed to shatter when they hit something. Imagine navigating the pandemic without rare earth materials. If the pandemic was a night- mare, how much worse would life have been without all the miracle products most people use every day but could not make on their own? You might be able to use innovative methods to grow food, and you could probably figure out how to sew or knit something to wear, especially if you have a stash of yarn. But what if you had to walk instead of drive and could not access Netflix or any other internet staple? What if you had no national or international news, no way to contact people except face- to-face, and the only way to mow your lawn was with a push mower? Even glass depends on rare earth minerals for polishing, color and optical properties; digital camera lenses in cellphone cameras, for example, may consist of 50% lanthanum. No lanthanum might eventually mean no more selfies — which would be hard on many people who love taking pictures of themselves to share with friends and family. Rare earth elements are essential in our high-tech society, whether we think about them or not. What exactly are they? • Rare earth elements are metals. • Their colors range from silver to gray. • These elements are soft, ductile, mal- leable and usually reactive. “Mallea- ble” means you can press or hammer them, and they won’t break; “ductile” means you can make metal wire or thread from them. • They can become more reactive under some circumstances, such as when you heat them or divide them finely. A Swedish army lieutenant, Carl Axel Arrhe- nius, is credited with discovering the first rare earth mineral in 1787. It was black, and he found it in a small-town quarry near Stock- holm. (The town was named Yttrby, which is how yttrium got its name in the periodic table.) Isolating the first rare earth element, however, didn’t happen until 1803. Initially, experts thought rare earths were scarce, which is why they have the name they have. However, that turned out to be a mis- take. In general, they are relatively abundant. Cerium is the 25th most common element; thulium and lutetium are the least common. There are 17 of them: scandium, yttrium and 15 lanthanides. In atomic order, the rare earth elements are listed below: NAME ATOMIC NUMBER COMMENTS SCANDIUM (SC) 21 PRODUCES LIGHT THAT RESEMBLES SUNLIGHT AND IS USEFUL IN ALUMINUM ALLOYS YTTRIUM (Y) 39 USED IN LEDS, PHOSPHORS (ESPECIALLY RED ONES), LASERS AND SUPERCONDUCTORS LANTHANUM (LA) 57 USED IN BATTERIES, CATALYSTS, GLASS CERIUM (CE) 58 USED IN CATALYTIC CONVERTERS, LEDS PRASEODYMIUM (PR) 59 USED IN PERMANENT MAGNETS; CERIUM OXIDE POLISHES GLASS AND IS USED IN CATALYTIC CONVERTERS NEODYMIUM (ND) 60 USED IN PERMANENT MAGNETS USED FOR MICROPHONES, LOUDSPEAKERS, IN-EAR HEADPHONE, ELECTRIC MOTORS, COMPUTER HARD DISKS AND WIND TURBINE ELECTRIC GENERATORS PROMETHIUM (PM) 61 PROMETHIUM-147 CAN BE USED IN LUMINOUS PAINT AND ATOMIC BATTERIES AND CAN ALSO MEASURE THICKNESS SAMARIUM (SM) 62 USED IN HIGH-TEMPERATURE PERMANENT MAGNETS EUROPEUM (EU) 63 CAN BE PHOSPHORESCENT AND IS RELATIVELY NONTOXIC GADOLINIUM (GD) 64 USED INTRAVENOUSLY IN MRI CONTRAST AGENTS TERBIUM (TB) 65 PART OF PERMANENT MAGNETS USED IN ACTUATORS, NAVAL SONAR SYSTEMS AND SENSORS DYSPROSIUM (DY) 66 PART OF PERMANENT MAGNETS USED FOR DATA STORAGE HOLMIUM (HO) 67 USED IN POLEPIECES IN THE STRONGEST STATIC MAGNETS ERBIUM (ER) 68 HAS LASER SURGERY AND DENTAL LASER APPLICATIONS THULIUM (TM) 69 PROVIDES RADIATION IN X-RAY DEVICES AND SOME SOLID-STATE LASERS YTTERBIUM (YB) 70 USED IN LASER MEDIA AND STAINLESS STEEL LUTETIUM (LU) 71 USED IN METAL ALLOYS AND AS A CATALYST FOR SOME CHEMICAL REACTIONS MINING 14