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Haunted by 'Specter of Unavailability,' Experts Huddle Over Critical Materials

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Science  17 Dec 2010:
Vol. 330, Issue 6011, pp. 1598
DOI: 10.1126/science.330.6011.1598
Going critical.

A worker pours the rare earth metal lanthanum into molds at a workshop in China.

CREDIT: DAVID GRAY/REUTERS

When shipments of rare earth metals from China to Japan temporarily stopped in the wake of a territorial spat this autumn, high-tech companies around the world got an uncomfortable reminder that China owns a stranglehold on supplies of the coveted commodities. The episode might have attracted more attention than China hoped for. The U.S. Department of Energy (DOE) and counter parts in Japan and Europe have held workshops in recent weeks bringing materials scientists and policymakers together to brainstorm on how to ensure supplies of rare earths and other strategic minerals and to stimulate research on alternatives.

The meetings, at Lawrence Livermore National Laboratory in California in November and at the Massachusetts Institute of Technology in Cambridge, Massachusetts, earlier this month, are expected to help DOE chart a strategy for critical materials, participants say. The quickest fix for restricted supply would be boosting production outside of China. But no one expects breakthroughs on supply or alternative materials overnight.

Rare earths—elements 57 through 71 on the periodic table plus scandium and yttrium—are key components in products such as solar panels and hybrid cars. Around 95% of the current supply comes from China, which is holding back an increasingly large share of production for its own use (Science, 11 September 2009, p. 1336). The recent controversy over shipments to Japan has observers worried about China's willingness to squeeze supplies for political purposes.

“The specter of mineral unavailability” due to geopolitical risks or market imbalances haunts other elements as well, says Roderick Eggert, a mineral resources economist at the Colorado School of Mines in Golden. Most of the world's lithium, a key component in batteries for consumer electronics and electric vehicles, is mined in Bolivia. Congo and Zambia are the main sources of cobalt, used in high-strength alloys and as an industrial catalyst. Indium and tellurium, ingredients of photovoltaic cells and flat panel displays, are byproducts of, respectively, zinc and copper processing. Because availability of indium and tellurium depends on demand for copper and zinc, supplies of the two won't necessarily increase with increasing prices, Eggert says.

Even before China flexed its muscles, experts in other countries were fretting over critical materials. A few years ago, Toru Nakayama, who manages materials research programs for the New Energy and Industrial Technology Development Organization (NEDO) in Kawasaki, Japan, drafted a rare metal substitute development project while at the Ministry of Economy, Trade and Industry. Since 2007, NEDO has organized consortia of researchers from companies, universities, and institutes to work on reducing or replacing indium, dysprosium, platinum group metals, and four other elements in high-tech products. NEDO has provided $82 million over the past 4 years for these efforts. As that effort was getting started, the U.S. National Research Council warned in 2008 that a looming shortage of critical minerals could hinder adoption of emerging clean energy technologies. And last June, the European Commission released a report citing concerns over access to 14 critical raw materials.

On the rare earth supply issue, workshop participants agreed that immediate relief would come from “getting rare earth mines outside of China up to speed as fast as you can,” says Karl Gschneidner Jr., a metallurgist at DOE's Ames Laboratory and Iowa State University. Two rare earth mines—one in the United States and another in Australia—could come on stream in 2011, says Eggert. In the meantime, he says, manufacturers will be working to make more efficient use of the scarce minerals. Several NEDO projects aim to optimize manufacturing processes or tweak materials to get the same performance out of less mineral.

The toughest challenge may be to replace rare elements (Science, 26 March, p. 1597). Some materials have been in use for several decades, and “nobody has found substitutes yet,” says Gschneidner. For example, he says, phosphors in lighting and optics applications have unique properties difficult to find in other materials.

The workshops showcased some progress on replacements. One NEDO-funded group has produced a trial liquid crystal display that uses zinc oxide instead of indium tin oxide for some electrodes, reducing indium use by 45%. Dysprosium, used in the magnets in motors powering electric and hybrid vehicles, is another target. Several groups have developed dysprosium-free magnets, but they weaken at car motor operating temperatures, says Kunihiro Ozaki, a materials scientist at Japan's National Institute of Advanced Industrial Science and Technology. By tweaking grain properties and strictly controlling manufacturing, researchers hope to strengthen these magnets' thermal resistance—but that could take 5 years or more, Ozaki says.

Workshop participants came away with a clearer picture of what colleagues are doing in other countries. “It was very valuable to understand the extent of the program that's ongoing in Japan,” says John Hryn, a materials scientist at Argonne National Laboratory in Illinois. The first cooperative effort is likely to be between the geological surveys of the United States and Japan to assess rare mineral deposits around the world, Eggert says. Beyond that, Hryn says there are a number of ongoing projects at Argonne focused on magnets, phosphors, and catalysts that use rare earths, creating “opportunities for future collaborations.” These will take time to coalesce and bear fruit. In the meantime, China is sitting pretty with most of the rare earth cards.

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