Rare-earth elements (REEs) are also known as the lanthanide series in the periodic table of elements. They are not particularly rare in terms of abundance, but for many years remained rarely separated from each other due to their similar chemical characteristics.
Rare earth elements are widely used in mature markets (such as catalysts, glassmaking, lighting, and metallurgy) and in newer high-growth markets (such as battery alloys, ceramics, and permanent magnets. In mature market segments, lanthanum and cerium constitute about 80% of rare earth elements used, and in new market segments, Dysprosium, Neodymium and Praseodymium account for about 8% of rare earth elements used.
World mine production of rare earth oxides (REOs) grew rapidly (about 7% per year) from 1990 to 2006 and increased at a slower pace from 2008 till now with a break in 2007 due to the worldwide economic conditions. The growth in REO production directly correlates to the growth in REO consumption, which, in turn, has been tied to the general economic growth for the historic uses of REOs (catalysts for fluid cracking and catalytic converters for automobiles, glass and metallurgical industries, and phosphors) and the increase of high-technology uses tied mainly to alternative energy systems (such as batteries for hybrid cars) and permanent magnet applications for electric motors, stereo speakers, and wind turbine generators.
In 2008, 129,000 metric tons of REOs was consumed worldwide (Cordier and Hedrick, 2010). Mature applications accounted for about 60% of the total and the developing, high-growth sectors, the remaining 40%. (Bade, 2010).
The distribution of REO consumption by type is not homogeneous among market sectors. However, REO consumption is split rather evenly among the following applications: glass industry (polishing, 68%; additives, 42%), 28,400t; catalysts (fluid cracking, 72%; catalytic converters, 28%), 27,400t; Neodymium-Iron-Boron magnets, 26,300t; metallurgy and alloys, 23,600t; and other uses, 23,500t.
Due to their superior magnetic flux density, Neodymium-Iron-Boron magnets are in high demand for small and large motors and generators. Small (servo) motors power disc drives in computers, windows in automobiles, and multitudes of other everyday applications. Larger motors, such as those in electric cars, can use up to 200g of Neodymium and 30g of Dysprosium per motor (Keane, 2009). Wind turbine generators can contain 1t of Neodymium per megawatt of electric capacity generated (Barton, 2009).
In 2008, 26,300 t of REOs was used in this category, of which Neodymium oxide accounted for 69%; Praseodymium oxide, 23%; Dysprosium oxide, 5.0%; Gadolinium oxide, 2.0%; and Terbium oxide, 0.2%.