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The rare earth blues

At this week’s enormous materials science meeting in Boston, Massachusetts, there are scores of talks and posters dealing with the rare earth metals – the fifteen lanthanides, across the bottom of the periodic table, plus scandium and yttrium – which are used in everything from mobile phones to powerful magnets and lasers. But while scientists like those at the Materials Research Society (MRS) event are busily manipulating these atoms, the world has been fretting over their availability.

Fears over these slightly misnamed and actually quite abundant elements surged earlier this year when China moved to restrict its export quotas. China produces nearly all of the world’s supply of rare earth elements.

These concerns have not escaped the notice of the MRS, which has set up a group to look into what it calls ‘energy critical elements’. Alex King, director of the US Department of Energy’s Ames Laboratory in Iowa, a past president of the MRS and a member of that group, told the meeting that since 2001 the price of lanthanum oxide has increased 3,157% and the price of cerium oxide has seen a 4,493% increase.

These increases in price have led to the same countries that abandoned rare earth mining in the face of environmental and cost concerns to think again, says Yan Wang of the Institute of Rare Earth at Baotou in Mongolia.

“Due to the increasing demand for rare earths there are many companies trying to develop projects in other countries,” Wang told another session at the meeting.

She highlights plans for the Molycorp Minerals company, headquartered in Greenwood Village, Colorado, to restart production of rare earths later this year at its Mountain Pass facility in California, which was mothballed at the start of the century due to falling prices and environmental issues. Other companies are also hoping to capitalise on demand for rare earths, and the concern over China’s dominance. Wang also cites the Lynas Corporation of Sydney, Australia, which is exploiting what it calls the “the richest known deposit of rare earths in the world ” at Mount Weld in Australia and plans to start supplying customers by 2011.

More mining is just one possible method of mitigating the current shortage. Other options include increasing recycling and research into possible replacements for shortage elements, such as new high-power but rare-earth-free magnets.

King and his colleagues are working on a joint MRS and American Physical Society (APS) report into energy critical elements – those where a shortage could impede the deployment of a new energy technology. For example, a hybrid car uses about 3kg of neodymium, while a 3MW wind turbine requires 700kg.

Neither the co-chair of the MRS / APS group Robert Jaffe, nor other members of the group at a briefing on the topic, would be drawn on what the group’s recommendations will be, as these have yet to be ratified by the MRS and the APS.

However Jaffe, a physicist at the Massachusetts Institute of Technology, Cambridge, notes that while the US has an Energy Information Administration to collect and make available statistics on energy, there is no similar group tracking materials. “One of the things that clearly would help everybody involved is high quality information,” he told another session at the meeting.

More research funding could also help, both by leading to techniques that expand the availability of these elements by, for example, allowing extraction of new sources and reducing dependence on them by finding alternatives.

“A lot of the issues here are amenable to concentrated research,” says Jaffe. “A lot of the problem here is recognising the very long lead times. Long lead times are hard for corporations to deal with, it’s normally the purview of government sponsored research.”

When asked by Nature, Jaffe would not be drawn on how much additional funding might be required. He did say that stockpiling rare earth elements does not seem a good option.

The focus of the group looking into energy critical elements includes not just rare earths but also platinum group elements and others such as tellurium, which is used in some thin-film photovoltaic panels. The days when only a small number of elements were important is long over. “In the long run, the whole periodic table of elements is in play in the world of materials,” says Jaffe.

Or, in the words of King, “We have to learn from our experience with rare earths because tomorrow it will be something else.”


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