Rare earth metals
A look at 17 chemical elements vital for gadgets of today, green technologies of tomorrow
What are they?
Rare earth elements, or REEs, are a group of 16 metals (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, weapons and 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 the energy efficiency of light bulbs, and their ability to store hydrogen makes them a key ingredient 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:
|Flat-screen displays, lasers|
|Gadolinium||Computer memory, CDs, nuclear reactor shields|
|Terbium||Efficient light bulbs|
|Lightweight, high-strength magnets used in electric motors|
|Holmium||Super-strong magnets, nuclear reactor control rods|
|Vanadium steel, fibre optics, amplifiers|
|Thulium||Lasers, portable X-rays|
|Ytterbium||Infrared lasers, earthquake-monitoring equipment|
|Lanthanum||Hybrid car batteries, night vision goggles|
|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 as lead, 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.
Currently, China is the de facto supplier of rare earth metals around the world; it accounts for 50 per cent of the world's rare earth element deposits, but 95 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 cutting its 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 business to the more lucrative market of manufacturing finished products that use the metals.
China was not always the main supplier of REEs. From the mid-1960s to the 1980s, the main source of the minerals was 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 discovered by 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 from dozens of sites in international waters, drilling up to 50 metres below the sea bed, and found particularly high concentrations in the eastern South Pacific, west of Peru and Ecuador, and the central North Pacific, near Hawaii.
The scientists said the deposits are potentially greater than China's reserves and richer in the heavier, more lucrative rare earth metals. They said their samples indicate the presence gadolinium, lutetium, terbium and dysprosium — all heavy REEs.
The find presents new hope for those worried about China's supply drying up, but also poses enormous challenges not only because of the difficulties in extracting the metals from depths of 4,000 to 5,000 metres but also because of potential fights over which country has rights to the deposits.
As Chinese exports of REEs dry up and prices rise, more companies are also looking to recycle rare earth metals from discarded electronics.
Since 2000, global demand for REEs has tripled, from about 40,000 tons to 120,000 tons, and experts estimate it will reach 200,000 tons by 2014.
Japan's electronics and car companies account for about one-third of the global demand for rare earth metals. Toyota is one major client. Each of its hybrid Prius cars uses 15-16 kg of rare earth metals. (The company said in March that it had sold three 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 in Vietnam.
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 experts estimate that it takes about seven to 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, it is about three decades behind China in terms of exploiting them. It has dozens of companies that are exploring for 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 isolate and refine the 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 are released during the extraction process.
When announcing the further scaling back of exports earlier this year, China said it would tighten environmental controls on rare earth mining 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 radioactive elements and phosphorus.