Description
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Samarium is a lanthanide that has a bright silvery white color in its natural solid state. It oxidizes quickly in air and will even ignite in air at heated temperatures. Samarium has an atomic weight of 150.36, a melting point of 1962 °F, and a boiling point of 3261 °F. Some common uses of samarium include: as a component with other rare earth metals for carbon arc lighting, as a component in alloys used in headphones, as a chemical reagent for some reactions, and as a neutron absorber used in nuclear reactors.
Isolation
Samarium is never found free in nature; it occurs in minerals which also contain other lanthanides and rare earth metals. Extraction processes can be used to isolated samarium from these other elements.
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The isolation process of samarium, as with other lanthanides, is extremely complicated. Samarium occurs in such minerals as bastnasite, monazite, samarskite, and Mish metal; these minerals also contain many other rare earth elements and lanthanides that have similar chemical properties further complicate the extraction and isolation process. The procedures that are used to isolate samarium from the minerals it occurs in involve ion exchange, solvent extraction, and electrochemical deposition. Further isolation with increased purity uses electrolysis procedures. As the isolation process is highly complex, samarium is never isolated on a small laboratory basis.
The first step to samarium isolation involves separating the lanthanides and rare earth metals by treating the minerals with sulfuric acid, hydrochloric acid, and sodium hydroxide. Once samarium is reduced using the procedures listed above, it is in its chloride form. Electrolysis of heated, melted, samarium chloride and sodium chloride in a graphite cell separates the chloride from the samarium yielding pure samarium.