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Science

Rare earth metals

An in-depth look at rare earth metals, vital components of everything from cellphones to hybrid car batteries, wind turbines and precision-guided weapons.

A look at 17 chemical elements vital for gadgets of today, green technologies of tomorrow

A labourer works at the site of a rare earth metals mine in Nancheng county in China's Jiangxi province on Oct. 31, 2010. China provides almost all of the global supply of the metals, which are key components of many electronics and green technologies. (Stringer Shanghai/Reuters)

What are they?

Rare earth elements, or REEs, are a group of 16metals (or 17 if scandium is included) that share particular chemical and physical properties that make them indispensable to the manufacture of countless electronics, appliances, green technologies, weaponsand medical devices. They are valued for their properties of luminescence, thermal and electrical conductivity, magnetism and ability to act as catalysts and polishing compounds.

They are considered vital not just for the many gadgets of today, such as cellphones, computers, stereos, flat-screen TVs and MRI machines but, perhaps more importantly, for the green technologies that many expect will define our future. They are a key component of manufacturers' efforts to produce more efficient, less-polluting versions of their products, such as cars and light bulbs, and of the global fight to reduce greenhouse gas emissions.

One of the areas where REEs have made the greatest contribution is in the miniaturization of magnets used in the motors and generators that power electronics, electric cars and wind turbines. REE alloys reduce the weight of such magnets by up to 90 per cent and allow them to function at high temperatures.

They also greatly improve theenergy efficiency of light bulbs,and their ability to store hydrogen makes them a keyingredient of hybrid car batteries.

REEs are divided into light and heavy elements, the latter being the more valuable.

Below is a list of REEs and some of their most common applications:

Element

Uses

HEAVY
Yttrium TV screens

Europium

Flat-screen displays, lasers
Gadolinium Computer memory, CDs,nuclear reactor shields
Terbium Efficient light bulbs

Dysprosium

Lightweight,high-strength magnets used in electric motors
Holmium Super-strong magnets, nuclear reactor control rods

Erbium

Vanadium steel, fibre optics, amplifiers
Thulium Lasers, portable X-rays
Ytterbium Infrared lasers, earthquake-monitoring equipment
Lutetium Petroleum refining
LIGHT
Lanthanum Hybrid car batteries, night vision goggles
Cerium Catalytic converters
Praseodymium Lasers, ceramic materials, aircraft engines
Neodymium Efficient motor magnets, disc drives, missile guidance systems, laser range-finders
Promethium Portable X-rays, nuclear batteries
Samarium Lasers, nuclear reactors, lighting, precision-guided weapons
*Scandium Efficient lights, metallic baseball bats (scandium is found in most deposits of REEs but is not always classified as a rare earth element)

How rare are they?

Rare earth elements are actually no rarer than common metals such aslead, tin, nickel or zinc. Even some of the scarcer REEs, such as thulium and lutetium, are still about 200 times more abundant than gold, for example.However, they are difficult to extract because they do not often occur in concentrations high enough to be mined efficiently and are hard to separate and refine.

Supply

Currently, China isthe defactosupplier of rare earth metals around the world; it accounts for 50 per cent of the world's rare earthelement deposits,but95 to 97 per cent of the global supply. Other minor suppliers include:Brazil, India, the Commonwealth of Independent States (Kyrgyzstan, for example) and Malaysia. Countries such as Canada, the U.S., Australia and South Africa have deposits of rare earth metals and are home to companies that are exploring how to extract them, but are years away from having functional mining operations.

In 2010, China announced it would be drastically cuttingits REE exports, causing a panic among the manufacturers that rely on the metals. It cut exports by more than 70 per cent in the second half of 2010 and announced it would cut exports by about 35 per cent in the second half of 2011. Since the early 2000s, it has reduced its supply from about 40,000-50,000 tons a year to roughly 31,000 tons a year today. Industry experts speculate that China will eventually focus its REE operations entirely on domestic production and move from the exporting businessto the more lucrativemarket of manufacturing finished products that use the metals.

As China curbs its exports of rare earth metals, the recovery of the metals from discarded electronics is becoming a growing industry. Here, a worker holds a scrap mobile phone at a recycling facility in Tokyo owned by Re-Tem Corp. (Toru Hanai/Reuters)

China was not always the main supplier of REEs. From the mid-1960s to the 1980s, themain source of the mineralswas a mine in Mountain Pass, Calif. The U.S. is looking at reviving its REE mining operations. A bill, called the Rare Earths Supply-Chain Technology and Resources Transformation Act, which aims to"reestablish a competitive domestic rare earth supply chain," is currently before several House committees.

Recently,a new source of REEs was discoveredby Japanese scientists. Researchers led by Yasuhiro Kato at the University of Tokyo said they discovered 100 billion tonnes of rare earth minerals in the deep-sea mud of the Pacific Ocean. They took samples fromdozens ofsites in international waters, drilling up to 50 metres below the sea bed, andfound particularly high concentrationsin the eastern South Pacific, west of Peru and Ecuador, and the central North Pacific, near Hawaii.

The scientists said the deposits arepotentially greater than China's reserves and richer in the heavier, more lucrative rare earth metals. They said their samples indicate the presencegadolinium, lutetium, terbium and dysprosium all heavy REEs.

The find presents new hope for those worried about China's supply drying up, but also poses enormouschallenges not only because of the difficulties in extracting the metalsfrom depths of 4,000 to 5,000 metresbut also because of potential fights over which country has rights to the deposits.

As Chineseexports of REEs dry up and prices rise, more companies are also looking torecycle rare earth metalsfrom discarded electronics.

Demand

Since 2000, global demand for REEs has tripled, from about40,000 tons to 120,000 tons, and experts estimate it will reach 200,000 tonsby 2014.

Japan's electronics and car companiesaccount for about one-third of the global demand for rare earth metals.Toyota is one major client.Each of itshybrid Prius cars uses 15-16 kg of rare earth metals. (The company said in March that it had soldthree million of the hybrids worldwide since it first went on sale in 1997.) Toyota Tsusho, a trading house affiliated with Toyota Motor Corp., is currently negotiating to secure exclusive mining rights to extract and refine rare earth metals inVietnam.

Mining

The majority of rare earth metals are currently mined at a huge open-pit mine near the city of Baotou in inner Mongolia called the Baiyunebo mine.There are also some smaller illegal mines in the southern part of the country.

Industry expertsestimate that it takes about sevento 15 years to make a mine operational. This is why China's reduction of exports has caused such concern, since there is no quick way to supplement the supply, and most countries that are exploring mining are still years off from functional operations.

Canada has about 56 per cent of the REE deposits outside China, but according to experts, itis about three decades behind Chinain terms of exploiting them. It has dozens of companies that are exploringfor rare earth metals, mainly in Quebec and Ontario,but no mining operations as yet.

The mining of rare earth metals poses environmental concerns, especially when waste is not properly disposed of, as has been the case in China. The acids and other chemicals used to isolateand refinethe elements pollute waterways and leach into the surrounding environment. Rare earth elements are also often found together with radioactive elements, mainly uranium and thorium,which arereleased during the extraction process.

When announcing the further scaling back of exports earlier this year, China said itwould tighten environmental controlson rare earthmining operations and clamp down on illegal mines. It said it would set new limits on the amount of pollutants used, such as ammonia nitrogen, and reduce the emission of radioactiveelements and phosphorus.