Re: REM Stream Log - Rare earth metals are absolutely...

Rare earth metals are absolutely critical to modern life. Fiber optic communications require erbium. Neodymium is a critical component in modern permanent magnets. Without a steady supply of rare earth metals, we would find ourselves in some difficulty, and things may get even more critical in the future—quantum memory may lie in the hands of praseodymium. Despite this need for rare earth metals, pretty much the entire supply comes from one country: China. In 2010, politicians finally noticed this, as China started restricting its export. In response, a team of researchers from the Netherlands and the United Kingdom have been investigating our ability to recyclerare earth metals. China's open-pit mines In an apparent response to environmental pressure, China began to restrict the exportation of rare earth metals in 2010. At the time, China controlled 95 percent of the market. Manufacturers were rocked by the price fluctuations, eventually complaining to the World Trade Organization in an effort to stabilize supply. Even if you're suspicious of China's true motives, mining rare earths is a dirty job, involving some pretty vicious acids, bases, solvents—and the whole process raises the risk of miners breathing in a serious amount of radioactive dust. So whatever China's underlying motive was, cleaning up the mining industry is a good thing. At the time, rare earth mining and refining was performed by companies ranging in size from tiny backyard operations, right up to very large companies. The technologies used also spanned the range from primitive and inefficient to the modern and efficient. ("Efficient" is a relative term here; I mean more efficient than the low-technology scenarios.) But the plain fact is that mining rare earths (and mining in general) is a messy and damaging process. Not just in local damage to the environment—poor labor conditions can make for a shortened life expectancy. So even if new mines were opened (or old ones were re-opened), the lower concentration of rare earths in the ore would make it difficult to operate in a clean manner and to compete with Chinese mining operations. But quantifying those difficulties is not simple. To evaluate the environmental impact of a magnet's production, the researchers turned to the literature to figure out things like the contents of the ore, the strength and volume of solvents used, the amount of acid used, the amount of energy used, and (since the ore has radioactive products in it) the expected radiation dose that workers would be exposed to. Since every mine, refinery, and magnet manufacturer uses a slightly different process, the researchers broke their data up into a high-technology version of the process, a low-technology version, and a middle-of-the-road process. These represent low, high, and medium environmental impacts. For the mining operations, the main difference between high-technology and low-technology scenarios is human exposure to toxic elements. Although the main hazard is hydrogen fluoride, to provide a consistent measure of toxicity, the researchers expressed the total exposure as an equivalent dose of 1,4-dichlorobenzene. Under their units, one kilogram of neodymium oxide results in an exposure of between 36 and 320kg of 1,4-dichlorobenzene. To put this figure in perspective, the amount of 1,4-dichlorobenzene allowed in water is 75 micrograms per liter, and the LD50 (the dose that will kill half the specimens in a study) in rats is 500mg/kg. Extrapolating this to humans—always a risky business—we can say that about 40g will kill a person. All of this means that even the clean process is quite dirty, while the dirty process has the potential to be quite hazardous. Making the magnets and their protective coatings is also rather messy, but it's generally less so than the mining. Even if the neodymium were to be recycled, the initial costs of mining and the recurring cost of forming it into magnets stay with the magnet—but if the neodymium can be recycled many times, the mining contribution becomes small compared to the magnet manufacturing.