Extractive Metallurgy of Rare Earths

Selection of an appropriate leaching method for light REEs from Esfordi flotation concentrate based on mineral characterization

“…IV). This could be attributed to the complexation of REEs with fluoride (Krishnamurthy and Gupta, 2004;Khawassek et al, 2015). Monazite-xenotime is not attacked by HNO 3 or HCl at low temperatures (Jordens, Cheng, and Waters, 2013).…”

“…REEs and alloys that contain them are used in devices such as computer memory, rechargeable batteries, cell phones, catalytic converters, magnets, fluorescent lighting, and many more (Krishnamurthy and Gupta, 2004). China supplies about 94% of the REE demand, with the remaining 6% coming from Russia and Estonia, the USA, India, Malaysia, and Brazil (Zhanheng, 2011).…”

“…Other rare earth minerals that have been or are now used as REE resources include apatite, brannerite, euxenite, gadolinite, loparite, and uraninite. Allanite, apatite, and other phosphorite sources, eudialyte, fergusonite, floreneite, parisite, perovskite, pyrochlore, zircon, and a few other naturally occurring rare-earth-bearing materials are also considered potential rare earth resources (Krishnamurthy and Gupta, 2004). Ion adsorption clays containing about 0.05-0.2 wt.% REOs are another group of REE deposits (Moldoveanu and Papangelakis, 2012).…”

“…The general formula for apatite is Ca 5 (PO 4 ) 3 X, where X is a fluoride or chloride ion or a hydroxyl group. Apatite, containing an average of 0.1-0.8% REOs, is the main source of phosphate fertilizers and phosphoric acid (Krishnamurthy and Gupta, 2004). The mode of occurrence and distribution of the rare-earth minerals in phosphate concentrates has generally ensured that they could be recovered only as by-products or co-products.…”

“…The mode of occurrence and distribution of the rare-earth minerals in phosphate concentrates has generally ensured that they could be recovered only as by-products or co-products. Chemical beneficiation or chemical processing of the concentrate obtained after physical beneficiation usually involves hydrometallurgical, and sometimes pyrometallurgical, operations (Krishnamurthy and Gupta, 2004).…”