Wednesday, November 3, 2010

Rare Earth Metals: The Periodic Table’s Undiscovered Country?

Recently gained press attention when the People’s Republic of China planned to reduce its export quota of rare earths back in October 21, 2010, are rare earth metals the periodic table’s “Undiscovered Country”?

By: Ringo Bones

As the only commercial producer of rare earth metals, the global economy got a bit spooked when the Beijing government decided to reduce its export of the valuable metals for its own domestic high tech use back in October 21, 2010. The hybrid car industry and the consumer electronics industry cannot function without rare earth metals, and yet an overwhelming number of us only had passive acquaintance of this quaint group of elements back in high-school chemistry. Does this mean that the rare earth metals or lanthanide metals truly are the periodic table’s “Undiscovered Country”?

Even though it is currently on the commodities traders hotspot du jour, from the perspective of the International Union of Pure and Applied Chemistry or IUPAC, the group of elements commonly referred to as the “rare earths” are neither rare nor earths. The rare earth family or group of elements are composed of soft, malleable metals – and most of them are not at all in short supply. Cerium, the most abundant, is more plentiful than tin or lead – while thulium, the scarcest, is only slightly rarer than iodine. The rare earth misnomer came about because these elements’ oxides not only have earth-like consistency and texture but where at first mistaken for the elements themselves.

All of the 15 rare earth elements have two outer electrons and eight or nine in the second shell in. They only vary in their electron compliment in the third innermost shell. But among the rare earth’s atomic structure, the third-shell electron difference is very slight indeed thus making the 15 elements a very close-knit family. From a mineralogical standpoint, a typical mineral containing a single rare earth element more often than not contains all of the other members.

The rare earth elements are so nearly identical in their chemical properties that separating them can easily involve thousands of steps. Because of this quirk of chemistry, the individual chemically pure rare earth elements did not became available in commercial quantities until the late 1950s – which only added to the group’s reputation as the “Undiscovered Country” of the periodic table of elements.

Nevertheless, the rare earth family in their less than chemically pure form has been used industrially since the early 1900s in the form of their naturally occurring mineralogical mixture. Later on, much purer and refined forms go into the making of powerful ceramic rare earth magnets like the samarium cobalt magnets used in the electric motors of hybrid cars.

For much of the 20th Century, more than a million pounds of low purity rare earth metals still go annually into the manufacture of an alloy called “misch metal” – German for mixed metal. Combined with iron, misch metal products are used in cigarette-lighter flints. But the main use of low purity rare earth metals is in iron and steel-making where it is used to absorb impurities and improve the steel’s texture and workability.

A mixture of rare earths combined with carbon produces the intense carbon arc lights once used to light up Hollywood before being superseded by more energy efficient light sources. And a large number of rare earth compounds go into the making of high-quality glass for computer monitor use by making the glass completely colorless. Or in other applications, by adding deep color depending on the combination used.

Even though the United States has more or less similar amounts of rare earth metals deposits as that of the People’s Republic of China, it has since closed down its mines and related purification facilities back in 1990 due to the fact that it can no longer produce rare earth metals in a way that’s economically competitive with Mainland China while still adhering to OSHA and EPA guidelines and American mine workers – unlike that of Mainland China – won’t work under slave wage conditions; Thus enabling Mainland China as of late to use its rare earth metals industry as geopolitical leverage.


  1. The "strangeness" of the rare-earth elements - i.e. The Rare-Earth Kingdom - is most appropriately summed up by Sir William Crookes during his 1887 address to the British Association in which he quoted: "These elements (rare earths) perplex us in our researches, baffle us in our speculations and haunt us in our dreams. They stretch like an unknown sea before us - mocking, mystifying and murmuring strange revelations and possibilities."

  2. Things might get more interesting in the rare earth front during the UN-sponsored 2011 International Year of Chemistry.