Information relevant to the environmental aspects of REE mining is limited. Alkaline igneous complexes have recently been targeted for exploration because of their enrichments in the heavy REEs. In recent years, REEs have been produced from large carbonatite bodies mined at the Mountain Pass deposit in California and, in China, at the Bayan Obo deposit in Nei Mongol Autonomous Region, the Maoniuping deposit in Sichuan Province, the Daluxiang deposit in Sichuan Province, and the Weishan deposit in Anhui Province. Monazite-bearing placer deposits were important sources of REEs before the mid-1960s and may be again in the future. Ion-adsorption clay deposits in southern China are the world’s primary source of the heavy REEs. ![]() ![]() Carbonatites have been the world’s main source for the light REEs since the 1960s. Economic or potentially economic REE deposits have been found in (a) carbonatites, (b) peralkaline igneous systems, (c) magmatic magnetite-hematite bodies, (d) iron oxide-copper-gold (IOCG) deposits, (e) xenotime-monazite accumulations in mafic gneiss, (f) ion-absorption clay deposits, and (g) monazite-xenotime-bearing placer deposits. The systematic geologic and chemical processes that explain these observations are not well understood. The REEs also have a strong genetic association with alkaline magmatism. Many of the world’s significant REE deposits occur in carbonatites, which are carbonate igneous rocks. At least 245 individual REE-bearing minerals are recognized they are mainly carbonates, fluorocarbonates, and hydroxylcarbonates (n = 42) oxides (n = 59) silicates (n = 85) and phosphates (n = 26). The REE-bearing minerals are diverse and often complex in composition. ![]() New mine production began at Mount Weld in Western Australia, and numerous other exploration and development projects noted in this chapter are ongoing throughout the world. As a result, the global rare-earth industry has increased its stockpiling of REEs explored for deposits outside of China and promoted new efforts to conserve, recycle, and substitute for REEs. Citing a need to retain its limited REE resources to meet domestic requirements as well as concerns about the environmental effects of mining, China began placing restrictions on the supply of REEs in 2010 through the imposition of quotas, licenses, and taxes. Nickel-metal hydride batteries use anodes made of a lanthanum-based alloys.Ĭhina, which has led the world production of REEs for decades, accounted for more than 90 percent of global production and supply, on average, during the past decade. Neodymium-iron-boron magnets, which are the strongest known type of magnets, are used when space and weight are restrictions. The use of REEs in magnets is a rapidly increasing application. Lanthanum-based catalysts are used in petroleum refining, and cerium-based catalysts are used in automotive catalytic converters. ![]() The glass industry is the leading consumer of REE raw materials, which are used for glass polishing and as additives that provide color and special optical properties to the glass. Although REEs are not rare in terms of average crustal abundance, the concentrated deposits of REEs are limited in number.īecause of their unusual physical and chemical properties, the REEs have diverse defense, energy, industrial, and military technology applications. Email: rare-earth elements (REEs) are 15 elements that range in atomic number from 57 (lanthanum) to 71 (lutetium) they are commonly referred to as the “lanthanides.” Yttrium (atomic number 39) is also commonly regarded as an REE because it shares chemical and physical similarities and has affinities with the lanthanides.
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