Rare earths are a set of related metals close together on the Periodic Table of the Elements. The lightest of these is scandium. The creator of the periodic table, Russian Dmitri Mendeleev, had in 1869 predicted the existence of such an element below boron in the table.
Now, euxenite, ytterbite, and gadolinite are uncommon minerals found in Norway and Sweden. In the space of several decades ending around 1850, many new elements were found in these minerals. The elements became known as rare earths. Some time later, in 1879, a team at the university in Uppsala, Sweden, led by Lars Fredrik Nilson, examined his own samples of euxenite and gadolinite. He found yet another element and named it scandium after Scandinavia. Although we arrange the periodic table differently now, scandium had the properties predicted by Mendeleev.
Mining and Production
Scandium is not that uncommon in the earth's crust, but it is known as a rare earth because is seldom forms concentrated ore bodies. Two of the only concentrated sources are the minerals gadolinite and thortveitite. Actual mining of scandium, though, is a byproduct of other efforts, such as iron and uranium mining. Less than one tonne per year is produced.
Properties and Uses
Scandium is a soft, silvery metal that tarnishes in air. It is moderately reactive. Scandium has a low density and a rather high melting point.
The lanthanide series of rare earths is infamous for all having very similar chemical properties and thus being difficult to separate. Scandium is considerably lighter than the other rare earths, though, and its chemical properties are reasonably distinct. Reasonable chemical efforts will isolate it from the other rare earths that occur in the same minerals.
Scandium is primarily used as a minor alloy with aluminum. The scandium prevents large aluminum crystal forming, which can create weaknesses in the metal. Scandium aluminum is sometimes used in aircraft and also in sports equipment such as baseball bats and lacrosse sticks (right), similar to titanium.