Scandium, a silvery-white metallic element with atomic number 21, has a relatively low density and high melting point (around 1541 degrees Celsius). Though a transition metal, it is often grouped with rare earth elements like yttrium and the lanthanides due to their similar chemical behaviors and geological occurrences. Scandium is widely distributed across the Earth’s crust but rarely found in concentrated deposits, making its economic extraction challenging despite its valuable properties.
Scandium’s Natural Presence in Earth’s Crust
Scandium is broadly distributed throughout the Earth’s crust, found in minute quantities across more than 800 different mineral species. Its crustal abundance ranges from 18 to 25 parts per million, comparable to elements like cobalt and even surpassing the abundance of lead. Scandium seldom forms its own dedicated minerals in significant concentrations, instead existing as a trace impurity substituting for elements such as iron, aluminum, or titanium within various mineral crystal structures.
Minerals known to contain trace scandium include thortveitite (which can contain up to 45% scandium oxide), euxenite, gadolinite, bazzite, and kolbeckite. These scandium-bearing minerals are found globally, with notable occurrences in Scandinavia, Madagascar, China, Russia, Australia, and North America. Geologically, scandium can be present in mafic to ultramafic intrusions, lateritic clays formed by weathering, and certain pegmatite formations.
Commercial Recovery of Scandium
Commercial scandium is almost exclusively obtained as a byproduct from processing other ores or industrial materials, rather than from dedicated scandium mines. A significant source is bauxite processing for aluminum production, where scandium concentrates in bauxite residue (red mud).
Other primary byproduct sources include:
Processing of uranium, tungsten, and rare earth elements
Titanium dioxide production waste streams
Nickel and cobalt mining operations, particularly from laterite ores
Iron ore and zirconium processing
Leading countries in scandium byproduct recovery include China, which accounts for a substantial portion of global production, alongside Russia, Ukraine, Kazakhstan, and the Philippines. Canada and Australia are also emerging as significant contributors. Specialized hydrometallurgical techniques, such as solvent extraction and ion exchange, are employed to isolate and purify scandium. Commercial availability of scandium is directly dependent on the production volumes of these main commodities from which it is co-extracted.