Rare Earth Elements: A Beginner’s Guide

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Rare earth elements consist of a group of 15 metals. In most cases and usage patterns in the modern economy, these 15 elements are oxides. The names of the elements are Cerium, Dysprosium, Erbium, Europium, Gadolinium, Holmium, Lanthanum, Lutetium, Neodymium, Praseodymium, Samarium, Terbium, Thulium, Ytterbium, and Yttrium.

The bulk of the world’s supply of rare earth elements comes from the mineral bastnasite. Bastnasite is a mixed lanthanide fluoro-carbonate mineral (Ln F CO3) that is found in rocks called carbonatites.

Carbonatites are igneous carbonate rocks. Specifically, this means that the rock masses contain more than 50% carbonate minerals, and cooled from a melt. Despite extensive research, no one is entirely certain about the origins of carbonatites. The general viewpoint is that carbonatites are carbonate rocks that were buried deep enough to melt via metamorphic processes or in the presence of igneous intrusions. Some geochemists have speculated that carbonatites can form when mantle rocks melt in the presence of carbon dioxide. There is almost always significant calcite in carbonatites.

Most carbonatites are intrusive igneous rocks. Structurally, they occur as volcanic plugs, dikes and cone sheets. Carbonatites often occur as smaller components of large igneous intrusions of silicate rocks, such as nepheline syenite. In these cases the general term is to refer to a “carbonatite complex.”

According to the geological literature, there are about 330 known occurrences of carbonatites worldwide, but almost all are small and noncommercial. There are only a few carbonatite deposits of commercial significance in the world.

Currently there are two deposits that are up and running. One is at Mountain Pass, California and operated by Molycorp, a subsidiary of Chevron (formerly owned by Unocal). The other major deposit is at Baiyun Ebo in Inner Mongolia, China. Mount Weld, Australia is also a large commercial body in development stages.

Major Uses of Rare Earth Elements

Lanthanum comes from the mineral bastnasite, and is extracted via a method called “solvent extraction.” Lanthanum is a strategically important rare earth element due to its activity in catalysts that are critical in petroleum refining. By one estimate, lanthanum “cracking-agents” increase refinery yield by as much as 10%, while reducing overall refinery power consumption.

Cerium is the most abundant of the rare earth elements. Cerium is critical in the manufacture of environmental protection and pollution-control systems, from automobiles to oil refineries. Cerium oxides, and other cerium compounds, go into catalytic converters and larger-scale equipment to reduce the sulfur oxide emissions. Cerium is a diesel fuel additive for micro-filtration of pollutants, and promotes more complete fuel combustion for more energy efficiency.

Neodymium is a critical component of strong permanent magnets. Cell phones, portable CD players, computers and most modern sound systems would not exist in their current form without using neodymium magnets. Neodymium-Iron- Boron (NdFeB) permanent magnets are essential for miniaturizing a variety of technologies. These magnets maximize the power/cost ratio, and are used in a large variety of motors and mechanical systems.

Europium offers exceptional properties of photon emission. When it absorbs electrons or UV radiation, the europium atom changes energy levels to create a visible, luminescent emission. This emission creates the perfect red phosphors used in color televisions and computer screens around the world. Europium is also used in fluorescent lighting, which cuts energy use by 75% compared to incandescent lighting. In the medical field, europium is used to tag complex biochemical agents which helps to trace these materials during tissue research.

Praseodymium comprises just 4% of the lanthanide content of bastnasite, but is used as a common coloring pigment. Along with neodymium, praseodymium is used to filter certain wavelengths of light. So praseodymium finds specific uses in photographic filters, airport signal lenses, welder’s glasses, as well as broad uses in ceramic tile and glass (usually yellow). When used in an alloy, praseodymium is a component of permanent magnet systems designed for small motors. Praseodymium also has applications in internal combustion engines, as a catalyst for pollution control.

Yttrium is rare in bastnasite, so is usually recovered from even more obscure minerals and ores. Still, almost every vehicle on the road contains yttriumbased materials that improve the fuel efficiency of the engine. Another important use of yttrium is in microwave communication devices. Yttrium- Iron-Garnets (YIG) are used as resonators in frequency meters, magnetic field measurement devices, tunable transistors and Gunn oscillators. Yttrium goes into laser crystals specific to spectral characteristics for high-performance communication systems.

Other Rare Earth Elements

Most of the remaining lanthanides fall into the group known as the “heavies” and include: Samarium, Gadolinium, Dysprosium, Terbium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium.

Samarium has properties of spectral absorption that make it useful in filter glasses that surround neodymium laser rods.

Gadolinium offers unique magnetic behavior. Thus this element is at the heart of magneto-optic recording technology, and other technology used in handling computer data.

Dysprosium is a widely used rare earth element that helps to make electronic components smaller and faster.

Terbium is used in energy efficient fluorescent lamps. There are various terbium metal alloys that provide metallic films for magnetooptic data recording.

Holmium is exceedingly rare and expensive. Hence it has few commercial uses.

Erbium has remarkable optical properties that make it essential for use in long-range fiber optic data transmission.

Thulium is the rarest of the rare earth elements. Its chemistry is similar to that of Yttrium. Due to its unique photographic properties, Thulium is used in sensitive X-ray phosphors to reduce X-ray exposure.

Ytterbium resembles Yttrium in broad chemical behavior. When subject to high stresses, the electrical resistance of the metal increases by an order of magnitude. So ytterbium is used in stress gauges to monitor ground deformations caused, for example, by earthquakes or underground explosions.

Lutetium, the last member of the Lanthanide series is, along with thulium, the least abundant. It is recovered, by ion-exchange routines, in small quantities from yttrium-concentrates and is available as a high-purity oxide. Cerium-doped lutetium oxyorthosilicate (LSO) is currently used in detectors in positron emission tomography (PET).

Byron King
for The Daily Reckoning Australia

Byron King
Byron King currently serves as an attorney in Pittsburgh, Pennsylvania. He received his Juris Doctor from the University of Pittsburgh School of Law in 1981 and is a cum laude graduate of Harvard University. Byron is also co-editor of Outstanding Investments.
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Comments

  1. Zzzz… Zzzz… Zzzz…

    Reply
  2. The world is just as addicated to Rare Earths as we are to oil – we just don’t know it…

    so what I hear you say… well China controls approximately 98% of the world’s production – and they understand the strategic nature of the position they have.

    Reply
  3. Hi, all,

    Is there anyone here know what is the import duty rate for Lanthanum Oxide (4N or 5N) in the US? What is its tariff code?

    Thank you for your help.

    Best regards,

    Nina Lu

    Reply
  4. Hello:

    The import duty into the US for La2O3 is 3.69%.

    Michael

    Michael Roche
    July 16, 2008
    Reply
  5. […] this place, come to think of it. Copper, gold, LNG, lithium, tantalum, coal, molybdenum, bauxite, rare earth elements…the list is very long. If Australia ever developed the capacity to build finished goods, it […]

    Reply
  6. Hi, just a simple question; what is so important about rare earth elements? why we do research about these REE? thanks

    Reply
  7. If Interested in a large green-field prospect of a variety of rare earths drop me a line.

    Reply
  8. Today the world leaders arrive in Kobnhaven… i saw how disgustingly pollutive the extraction of REEs are.. ammonia, strong acids etc and that China is considering restricting export of these elements (currently supplying 95% of the world market). I live in Australia and wonder how aussies would feel about Aus going into production of REEs considering how pulluting they are to the local envirinment/watertable, on which Australia is heavily dependent – our continent being so dry! Yet these elements are so strtegic to modern thechnologies! I am surprised the debate over them is not more out in the public arena!

    Reply
  9. This is such an oxymoron: destroy and pollute the atmosphere to make more ‘green’ commodities! The process of extracting the elements, negates the benefits of them! Can we not create a better solution?

    Reply
  10. There is only one answer – reduce the demand, cap the population, effcetive recycling of what we have already got

    Reply
  11. Maybe you could edit the post name Rare Earth Elements: A Beginner’s Guide to more better for your webpage you make. I enjoyed the post nevertheless.

    Reply
  12. You cant fool all the people all the time. Rare-earth is also used is the composites of stealth technology, like unmanned drones and other Eco opponents.

    Reply
  13. To answer Damon Blake’s question, Australia is doing something about it, Lynas Corp is mining and concentrating its rare earths at its Mt Weld mine and sending it on a nice long journey to a backwater country (Malaysia) for processing. Apparently to be sent in unmarked trucks by road through to Fremantle instead of the originally earmarked Esperance. Interesting how the nice folk will have to immediately slap radioactive material stickers on the concentrates once they hit Malaysian shores…..

    Reply

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