Description
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Scandium is one of the transition metals that is a silvery white solid in its natural state. It is considered to be a rare element, and when it is exposed to the air it develops a yellow or pink type color. Scandium has an atomic weight of 44.955912, a melting point of 2806 °F, and a boiling point of 5126 °F. Some common uses of scandium include: as a component in mercury-vapor lamps and high-intensity lights, in its radioactive isotope form for the use as a tracing agent in oil refineries, and as a component in metallic alloys.
Isolation
Scandium is very rare and has never been found free in nature, and so it is isolated on a small scale for commercial purposes.
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Scandium for isolation purposes is collected from minerals such as euxenite, gadolinite, and thortveitite. Up to 40% of the mineral thortveitite is composed of scandium yttrium silicate; this is the main source for scandium that is used throughout the world. From thortveitite, pure scandium metal can be isolated by reacting scandium fluoride with the metal calcium; this is a reducing type reaction.
Another source of pure scandium is through uranium tailings that are a byproduct of uranium ore processing. Small amounts of pure scandium can also be isolated from tungsten tailings that are produced from tin smelters used to produce cast iron.
Originally, a tiny amount of scandium was isolated by heating a mixture of potassium, lithium, and scandium chlorides to approximately 1472 °F and then performing electrolysis on the heated mixture. Liquid zinc was the medium for the reaction, and tungsten wires were used as the electrodes in a crucible composed of graphite.