Even though there are other minerals that contain a significant amount of rare earth metals, is monazite the only mineral that is a commercially source of rare earths?
By: Ringo Bones
Ever since the People’s Republic of China’s rare earth metals industry gained widespread press notice back in October 21, 2010, the global commodities markets has since set their eyes on – which just a few weeks ago - the least discussed part of the Periodic Table, namely the rare earth element - not only the elements but their source minerals too. Given that there are a number of minerals that became important sources of rare earth elements since the end of World War II, is monazite truly the only economically viable source of rare earths for use in the consumer electronics industry and other high tech pursuits of the 21st Century?
The mineral monazite is a phosphate of cerium and other metals: like sister rare earth metals lanthanum, dysprosium, praseodymium and others of commercial importance like thorium. Monazite is a yellowish, reddish, or yellowish brown usually formless mineral with a hardness of 5 on the Mohs’ Scale. It occurs as an accessory mineral scattered in small grains through continental granites and granite gneisses and very rarely in larger masses in granite pegmatites.
The only commercial occurrence of this mineral is in rolled placer grains in river and beach sands which have been derived from granite terrains. The principal uses of monazite have been as a source of thorium for making incandescent gas mantles and the thoriated tungsten filaments of vacuum tubes; and also of cerium for pyrophoric cigarette lighter flint / misch metal alloys.
Monazite, as a sole ore of thorium, became of paramount importance in World War II as a raw material for the development of atomic energy. The Travancore Coast of India at the time was the principal source of monazite sand. This mineral has also been mined on the coasts of Brazil and Florida before the People’s Republic of China began developing their own monazite deposits.
The post World War II scientific and academic interest on the chemistry and properties of rare earth metals had made methods of purifying this now indispensible commodity more or less a freely shared scientific knowledge. It is somewhat of a no brainer that Mainland China eventually cornered the rare earth metals market by default since miners there work for slave’s wages and rare earth purification knowledge is already akin to a genie that’s already out of the bottle. In Mainland China, the monazite is as if it is there for the picking – commercially viable picking for rare earths.