Description
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Lanthanum is a lanthanide that is a silvery white solid in its natural state. It is soft enough to be cut with a knife, and oxidizes quickly when exposed to air. Lanthanum has an atomic weight of 138.9054, a melting point of 1688 °F, and a boiling point of 6267 °. Some common uses of lanthanum include: as a component in carbon lighting, in the manufacture of special optical glasses, as a component in cast iron, and as a catalyst for petroleum cracking.
Isolation
Lanthanum is only found in nature along with other minerals, and it is particularly present with minerals which contain rare earth elements. Isolation of lanthanum is highly complex.
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Lanthanum is more commonly found in such mineral ores as monazite and bastnasite; both of these minerals can be composed of more than ¼ of lanthanum in the form of LnPO4 and LnCO3F. Lanthanum extraction and isolation is complex because it is difficult to separate it from the other compounds it occurs with; monazite also contains radioactive elements so it must be handled with caution. The isolation process of lanthanum begins with extracting the metal out in salt form from the ores with sulphuric acid, hydrochloric acid, and sodium hydroxide. Further isolation procedures involve complex techniques including solvent extractions and ion exchange chromatography.
Lanthanum can also be extracted from its fluoride by reacting it with metal calcium. Lanthanum fluoride undergoes a reduction reaction with pure calcium metal to form lanthanum and calcium fluoride. The isolation of lanthanum is rarely carried out on a small scale laboratory basis as the isolation process is just too complex.