Above: These are crystals of praesodymium (green) and dysprosium (yellow) fluoride. These rare-earth salts are combined with purified calcium and "reduced" to yield the pure rare-earth metals and calcium fluoride. Courtesy Critical Materials Institute.
Image in slider: Extruded Europium (Eu) Metal. The colors arise from various levels of oxidation. The banding is from surface texture variation arising from the extrusion process. Photo by the Materials Preparation Center. Courtesy Critical Materials Institute.
Research efforts address the United States’ shortage of rare earth metals
April 2013 - At 7 a.m., an average Joe awakes to the hum of his cell phone’s alarm clock. Once dressed, he drives his hybrid car to the train station, cracking open the window to light a cigarette. Upon boarding the train, Joe scans his iPod’s playlists while placing an earbud in each ear. Average Joe is having an average morning with a nonstop use of rare earth metals.
“Everything you do today is totally dependent on rare earth in one way, shape or form,” says Alex King, director of the U.S. Department of Energy’s Ames Laboratory in Ames, Iowa. He rattles off an exhaustive list from the magnets used in a car’s window motors, engine and loudspeakers to the rare earths found in computer screens and in the flint of a lighter.
“The supply of rare earth is kind of critical to our life today,” he says. Recognizing this, the U.S. Department of Energy awarded Ames Laboratory up to $120 million over five years to develop solutions to the domestic shortages of rare earth metals and other critical materials. After negotiating terms, this research center, named the Critical Materials Institute, plans to conduct about 35 individual research projects, some with short-term answers and others with long-term goals. “The idea is to do things that are readily adoptable and transferrable to actual industry,” says King.
The current issue
“Until very recently there was essentially only one source [of rare earths], and that was in China,” says King. As China used rare earths more in its own domestic industries, exports from the country declined, “and so the rest of the world was suffering from a serious rare earth shortage.”
King says the goal of the Critical Materials Institute is to ensure the United States has an adequate supply of materials. “We do that by fundamentally three separate activities. One is trying to ensure there is a more diverse supply for these materials. Mining can be carried out economically in places other than China, so if one source goes offline, other sources can help make up the difference.”
The second strategy is to find alternative materials that deliver the same properties but without using supply-challenged materials like rare earths. The third strategy is to explore ways of using the same sources and technologies available today more efficiently. “That means manufacturing more efficiently so the buy-to-ship ratio goes up,” says King, noting the need to recycle more efficiently.
These three goals of the Critical Materials Institute must be underpinned with solid scientific research and economic analysis. “I think the biggest difference that we have from traditional research efforts is some very advanced and detailed economic analysis that sort of guides where we invest our research dollars,” says King.
Some projects are intended to make the rare earth extraction process more economical. “Rare earths are notoriously difficult to extract because they’re so chemically similar, so separating one from another is not an efficient process,” King explains. Separation produces low enrichment rates, meaning the process must be completed multiple times to get significant amounts of enrichment.
“One of our projects is to seek more selective chemistries so we can reduce the number of process steps,” he says. “That reduces the demand for water in the process, reduces the need for acids, organic compounds, all of which helps to reduce the cost of the project and the environmental impact. So the idea is by reducing cost and reducing environmental impact, you make it possible for corporate America to establish mines in more places.”
King and his research team hope to stabilize the supply chain of rare earths and other critical materials, “which means there’s an adequate supply of materials, the wait time for delivery of materials becomes more acceptable than it is today, and the price becomes stable,” he says, noting price stability as an indicator of success. With a stable price, “Current technologies can go forward and have access to the materials they use today.”
The invention of a new material that can replace an existing material could help stabilize the supply chain. However, King says, “The challenge with that is it’s very rare for a substitute material to exactly replicate the properties of the material it replaces. If you think about a magnet, its strength, shape and weight—all these things matter—and usually, even if you invent a material that’s better than what came before, that’s going to demand some redesign of the motors and other devices that the magnet goes into.”
King says the holy grail of this entire project would be the invention of materials that are close enough in properties to the materials they replace. If material A experiences a shortage because of outside factors like political issues or a natural disaster, material B can act as substitute until material A’s supply is stabilizes. “So if you’ve got two materials that can meet the same need then you’ve really got a solution that industry can use to control its costs and its supply chains,” says King. “That’s kind of rare.”
No news is good news
“One of the hallmarks of success for us will be, apparently, nothing happens,” says King. If there are no price spikes in the materials “for a while, we’ll claim success. If we’re really successful then maybe we’ll be like dentistry. The whole goal of dentistry is to stop tooth decay and if you get successful at that then dentists don’t have a job,” he continues. “We’re kind of like the dentists of the materials business.” MM
WHY CARE ABOUT RARE?
Despite their name, rare earth elements are quite common. They are the 17 elements, including the Lanthanides (and for some, scandium and yttrium) located one row up from the bottom on the periodic table. They are used in a wide range of applications, but magnets get the most attention.
The neodymium in the neodymium-iron-boron magnet is essential to making magnets. Currently this type of magnet is used in generators, wind turbines and in the drive motors of hybrid and electric vehicles.
Rare earths also are seen in high-efficiency lighting. Fluorescent lights operate using phosphors that contain terbium and europium, which glow when they’re hit by electrons. These two elements are used in most color displays of televisions, computers and cell phones. Rare earths are used as catalysts in the petroleum industry, as alloys in aluminum production, in aluminum grain refiners, for the lens on a camera, and more.