Dysprosium

Dysprosium (Dy, atomic number 66) is a lanthanide and is classed as a ‘heavy rare earth’ element.

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It is a soft metal with a silver lustre and extremely high magnetic strength. Dysprosium has recently gained a lot of attention in international affairs because of its growing importance in the clean energy industry (NdFeB alloy for wind turbine generators) and its extremely limited supply.

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Dysprosium occurs in the Earth’s crust at an average concentration of 6 ppm (parts per million), which makes it the 42nd most abundant element and, surprisingly, more than twice as abundant as tin. It is primarily extracted from monazite sand through ion exchange displacement processes. Although relatively abundant in the earth’s crust, commercial production is supply constrained. With production of rare earths concentrated in China (and to a lesser extent Russia) new mines in Australia and the United States scheduled for 2015 have failed to develop to end-product. Adding to this scarcity, the Chinese government sets export quotas. It is estimated that 1,702 tonnes of Dysprosium oxide was produced in 2013-2014, with 1,350 tonnes of this coming from China and a 35% shortfall in demand. This, along with a lack of suitable replacements, led the United States Energy Department to recently call it the single most critical element for emerging clean energy technologies.

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Dysprosium is in high demand primarily because of its application in neodymium magnets in electric motors and in rechargeable NiMH batteries. Neodymium-based magnets have recently led to an explosion in new electric and hybrid vehicle technologies because of their unparalleled magnetic power. Adding dysprosium to magnets, improves coercivity and temperature tolerance in them, allowing the magnets to maintain strength at much higher temperatures.

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Dysprosium’s magnetic qualities also make it useful in a new generation of gearless wind turbines. Wind power has become one of the most significant methods of sustainable energy sources and neodymium-based magnets, with small amounts of dysprosium, are central to this new and growing technology.

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Dysprosium has various other applications. Because of its high thermal neutron absorption cross-section, it is used in neutron-absorbing control rods in nuclear reactors. It is also a valuable addition to laser materials and strong commercial lights. Furthermore, it is sometimes used in hard disk storage devices.

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When Dysprosium was first identified by the French chemist Paul Emile Lecoq de Boisbaudran in 1886, he named it dysprosium from the Greek word dysprositos meaning ‘hard to get’ because it took him so many attempts to isolate. Given Dysprosium’s precarious supply and high demand, this name remains particularly fitting!

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