Transcript of "Nations Move to Head Off Shortages of Rare Earths"
Section Name D ownloaded from www.sciencem ag.org on M arch 27, 2010 PICTURE THE PERIODIC TABLE AS A CITY. ber is expected to grow to 200,000 which are heavily concentrated in particular You’ve got your ﬂashy downtown: gold, metric tons. ore deposits, rare earths are sparse. The world’s silver, and the like. You’ve got your China’s production of REEs has been richest veins of REEs contain only 4% to 9% of industrial sector: iron and nickel. There growing steadily over the past decade. the elements. Most deposits have 1% or less of are parks: carbon, oxygen, and nitrogen. But because its domestic demand for the elements—too little to make their process- And of course the “troubled” section: the elements has been growing even ing economical, says Mark Smith, chief exec- radionuclides. Then there are the forgot- faster, the country’s REE exports have utive ofﬁcer of Molycorp Minerals in Green- CREDITS (LEFT TO RIGHT): ISTOCK PHOTO; IZMOSTOCK/ALAMY ten, distant exurbs: the rare earth elements dropped from 75% of the total produced wood Village, Colorado, the only remaining (REEs), lanthanum (element 57) through to 25% (see ﬁgure, p. 1597). For a handful rare-earth mining company in the Western lutetium (element 71) along with scandium of elements—neodymium, dysprosium, Hemisphere. and yttrium. Sleepy no more, the exurbs have terbium, and yttrium—China is expected to In some cases, mining companies are turned very desirable. In recent decades, REEs use all it can produce sometime between 2012 responding. For example, in the United States, have become vital to a host of novel electron- and 2014, leaving the rest of the world out in the Molycorp plans to reopen a mine in Mountain ics and green-energy technologies. The trouble cold (Science, 11 September 2009, p. 1336). Pass, California, expected to produce up to is that, while researchers are steadily invent- “We are going to have to start acting 20,000 metric tons of rare earth oxides by 2012. ing new applications for rare earths, the supply quickly, or we will be in big trouble,” says Ed In Canada, Great Western Minerals Group and isn’t keeping up—and users of REEs are feel- Richardson, the sales and marketing manager Avalon Rare Metals hope to tap vast rare-earth ing the pinch. for Thomas & Skinner in Indianapolis, one of deposits in Saskatchewan and the Northwest Today, China supplies more than 97% the few makers of high-intensity magnets left Territories. However, rare-earth mining con- of all REEs, and increasingly the products in the United States, which relies on REEs to sultant Jack Lifton notes that these compa- from which they are made. Those products make its products. And with ever more appli- nies have not been able to secure all the funds span a wide swath, ranging from phosphors cations on the horizon, Richardson says, “the they’ll need to start in electronic displays, to magnets in disk problems we are seeing today are only going operations. drives, cell phones, to get worse over time.” REEs aren’t the only and MRI machines, concern. Supplies of other metals vital to and motors in missile electronics and green technologies—such as guidance systems. In indium and lithium—are also tightening 2000, about 60,000 as industrial uses for these materials metric tons of rare skyrockets. earth oxide ores were Rare earths are not rare. They mined worldwide. are ubiquitous in soils around the By 2014, that num- globe. But unlike gold and silver, Rare talent. The unique electronic structure of rare earths makes them vital for electronic displays, hybrid cars, and many other products.1596 26 MARCH 2010 VOL 327 SCIENCE www.sciencemag.org Published by AAAS
SPECIALSECTION 160 Prius, Toyota uses a kilogram of neodymium Losing ground. China produces nearly all the A Widening Gap for its electric engine and 10 kilograms of lan- 140 world’s rare earths. But as uses for the elements Metric tons (thousands) 120 increase, China’s exports of them are declining. thanum for its nickel metal hydride battery. In 100 January, a Toyota supplier also formed a part- 80 agencies to back REE mining and stockpiles, nership with a mine in Argentina to supply lith- 60 says Gareth Hatch, director of technology at ium for batteries for its next generation of plug- 40 Dexter Magnetic Technologies in suburban in hybrid vehicles. Production 20 Exports: oxides and compounds Chicago and editor of the RealMetalBlog. Lifton says other Western companies and Some manufacturing companies aren’t wait- governments need to act decisively, or they will 2002 2003 2004 2005 2006 2007 2008 ing for U.S. and Canadian mining companies to ﬁnd themselves frozen out of the market. “We New mining efforts are just the ﬁrst step. take action. Toyota recently made a deal with have 3 to 5 years to get it done,” he says. “AndCREDITS (TOP TO BOTTOM): ADAPTED FROM M. SMITH, MOLYCORP MINERALS; TEODOR TODOROV AT THE IBM T. J. WATSON CENTER; IZMOSTOCK/ALAMY Numerous rare earth oxides are invariably a rare-earth mine in Vietnam, securing sup- we haven’t even started yet.” mixed together in ores. They must be separated plies of neodymium and lanthanum. In a single –ROBERT F. SERVICE and puriﬁed, reduced to metallic form, and then alloyed, cast, and shaped. All the Western busi- D ownloaded from www.sciencem ag.org on M arch 27, 2010 nesses that used to do these extra jobs are gone Mission: Irreplaceable? and will need to be restarted. Setting up this full suite can cost hundreds SCIENTISTS ARE SCRAMBLING TO DEVELOP SUBSTITUTES FOR SCARCE ELEMENTS of millions of dollars and take up to a decade critical to industry. But the myriad uses of the elements make the effort an uphill struggle. “It’s worth- to accomplish, Lifton says. That’s enough to while to try and ﬁnd replacements,” says Peter Dent, vice president for business development at Elec- scare away most investors, who are interested tron Energy in Landisville, Pennsylvania. “But it won’t be easy.” in shorter term payoff. Investors also worry Dent’s company makes high-powered magnets used in electrical generators. Magnets have about a business that can be so easily manipu- increased in strength more than 100-fold over the past century—most dramatically in the 1970s lated by a single government, says Jeff Green, and 1980s, when researchers added samarium and neodymium to magnet alloys. The rare earths for- president of J.A. Green and Co., a government tify the alloys against outside magnetic ﬁelds, says Bill McCallum, a materials scientist at Iowa State relations ﬁrm in Washington, D.C., special- University and Ames Laboratory in Ames, Iowa. Such ﬁelds can easily depolarize (demagnetize) a izing in rare earths. China seems unlikely to magnetic material such as iron, McCallum notes, because iron lacks strong “anisotropy,” or preferred ﬂood the market today, but it did just that in orientation of its north and south magnetic poles. the 1980s and 1990s, driving most Western Adding neodymium, which has a strong anisotropy producers out of business. “It creates a really thanks to its electron structure, creates a much more unstable investment situation,” Green adds. powerful alloy. That property will be hard to replace, Green, Lifton, and others say plenty can says Jack Lifton, a rare earths consultant in suburban be done to get over such hurdles. Last month, Chicago, Illinois. magnet industry leaders in the United States Nevertheless, researchers are trying. George sent a letter to John Holdren, director of the Hadjipanayis, a physicist at the University of Del- U.S. Ofﬁce of Science and Technology Policy aware, Newark, says he and colleagues recently in Washington, D.C., calling on the Obama received funding to develop high-strength mag- Administration to take prompt action to restore netic materials made from neodymium, iron, and rare-earth mining and processing in the United boron nanoparticles that they developed in 2007. New recipe. Experimental CTZS solar cells States and other Western countries. The recom- Neodymium-iron-boron magnets are the stron- at IBM are rare-earth–free. mendations included establishing short-term gest conventional magnetic materials; mixing the stockpiles of rare earths critical for defense elements at the nano-scale should yield at least as much magnetization with less neodymium, needs and having the U.S. Department of Hadjipanayis says. First, though, the team must make large three-dimensional collections of such Energy set up a $2 billion loan-guarantee pro- nanoparticles and align their crystallographic axes—so far, a tall order. gram to help Western mining companies build Other efforts are further along. Solar cell makers have been working for years to perfect semi- new mining and processing facilities. Con- conductor alloys made from ultrathin ﬁlms. The most successful use indium, the price of which has gress has already drawn up a bill to push spiked to more than $1000 a kilogram in recent years. Researchers have made alternative versions such efforts, though it has yet to be from abundant elements, such as copper, zinc, tin, and sulfur (CZTS). And last month, researchers at introduced. IBM reported in Advanced Materials that they had increased the sunlight-to-electricity efﬁciency of Such efforts could get a boost CZTS cells by 40%, to 9.6%—less efﬁcient than indium-containing cells but close to the threshold early next month when the Gov- of 10% considered critical for commercialization. ernment Accountability Ofﬁce Researchers around the globe have also been toiling to replace indium used in transparent con- (GAO) is scheduled to release ductors in electronic displays. Last year, a team led by materials scientist Yang Yang of the University an interim report on the vulner- of California, Los Angeles, reported in Nano Letters that it had developed highly conductive transpar- ability of defense applications to ent ﬁlms by layering graphene (single-atom-thick sheets of carbon) and carbon nanotubes. The ﬁlms rare-earth shortages. If GAO deter- aren’t as good as ITO yet. But an analysis last year by Nano Markets, a market research ﬁrm in Glen mines that particular rare earths are Allen, Virginia, suggests that novel transparent conductors could soon ﬁnd widespread use. vital to national security, it “could really –R.F.S. get the ball rolling” in prompting government www.sciencemag.org SCIENCE VOL 327 26 MARCH 2010 1597 Published by AAAS