Dysprosium is a member of the lanthanide series of elements, or rare-earths. Like the other rare-earths it is never found as a free element in nature. Although many of the rare-earths are highly reactive, dysprosium is less so and the surface of the metal does not oxidize rapidly in air, unless it is in a highly-divided form like powder.
Derivation: Dysprosium is obtained as a by-product in the commercial removal of yttrium and other metals, primarily from carbonatite or ion-absorption clay deposits. To isolate dysprosium, the majority of the unwanted metals are first removed magnetically or by flotation process. Dysprosium is then separated from other rare-earth metals by solvent extraction and ion exchange processes.
Dysprosium is useful in the manufacture of control rods for nuclear reactors for its high thermal neutron absorption cross-section, and in data storage applications for its high magnetic susceptibility. Dysprosium may also be used, along with vanadium and other elements, in making laser materials and in commercial lighting.
Hazards: Soluble dysprosium salts, such as dysprosium chloride and dysprosium nitrate, are mildly toxic when ingested. Dysprosium powder may present a fire or explosion hazard when mixed with air and in the presence of an ignition source. Very thin foils of dysprosium may be ignited by sparks or by static electricity. Dysprosium fires must be put out using class D dry powder extinguishing agents. Water should not be used as the metal may react with water under fire conditions to evolve flammable hydrogen gas.