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Rare earth elements and global energy strategy

12/6/10

Economic and geopolitical trends suggest the supply of rare earth elements (REEs) will not be able to keep up with global demand. A concern is growing as China, which controls about 95 percent of the world's REE exports, has indicated that it might reduce its international trade in the metals. These elements are critical components in the development of clean energy products and have applications in defense and high-technology manufacturing.

Laura Lewis, the Cabot Professor and chair of the Chemical Engineering Department at Northeastern University, leads the nanomagnetism research group. She is working to produce magnets that are not reliant upon REEs but have the same strength. In 2008, she was also part of a breakthrough research team that discovered a way to reduce the cost of rare earth-based, high-strength magnets in an environmentally friendly way.

Here Lewis explains how the global market and demand for REEs has changed over time and how these elements will affect the future of engineering.

What are rare earth elements (REEs)? Why are they so important?

Rare earth elements are a family of 17 chemical elements in the periodic table, namely scandium, yttrium and the 15 lanthanides. Despite their name, they are not particularly rare in the Earth's crust. However, their global distribution is very uneven, with the proven reserves largely distributed in China (43 percent), the Commonwealth of Independent States (19 percent), the United States (13 percent) and Australia (5 percent). Most of the global REE production, however, is in China, with estimates ranging from 93 to 97 percent.

These elements have a unique arrangement of electrons that lends special properties to materials containing REEs. Among these properties is one that lends incredible magnetic strength to magnets made with REEs.

What are REEs used for, and what are some potential solutions to supply concerns?

The electronic properties of REEs provide the functionality to a variety of important technological applications, including light alloys for aerospace components, battery electrodes, catalysts and lasers.

In particular, perhaps the greatest vulnerability lies in the risk to the production of very strong magnets, sometimes known as "supermagnets."

Magnets are integral to motors, actuators and generators; they provide the mechanism to turn mechanical energy to electrical energy, and vice versa. The stronger the magnet, the more energy-efficient the device can be, so these rare earth-containing supermagnets are utilized in computers, automobiles and other vehicles (including hybrid vehicles), consumer electronic products, medical products and systems and motors of all kinds. They add functionality to jet fighter engines, electronic countermeasure systems, missile systems and satellite communication systems. Magnets are also integral parts of alternative energy systems, such as those that harvest wind, wave and tidal power.

One potential solution to the challenge of creating ultra-strong, ultra-efficient magnets that do not contain REEs is that scientists revisit the fundamental magnetic properties and interactions in metals and alloys and attempt to recover the magnetic strength from other mechanisms in the materials. This is a very significant challenge.

How has the global market and demand for REEs changed over time, and what does it mean for the industry with China in control of the majority of global REE exports?

One expert estimates that the overall permanent market will average growth of at least 4 to 6 percent per year, with the total market for permanent magnets to grow to more than $20 billion by 2020. While there is much activity to revitalize domestic sources of REEs, it will take years before the United States has a reliable supply. Those facts have prompted the United States (in particular, the Departments of Defense and Energy) and European Union to fund basic research on reduced-REE content magnets, in attempts to come up with alternatives that are competitive with the supermagnets.

How would a shortage of rare earth metals affect the future of engineering? How will it affect global efforts to address climate change?

It would most certainly spur new creativity and new strategies to engineer and optimize rare earth-free compounds and alloys that can provide the same functionality as those that contain REEs. Partially due to the exodus of the rare earth-magnet processing industry in the mid-1990s to China, due to the sale of the United States' largest magnet manufacturer, little rare earth expertise remains in this country. It will be necessary to train future scientists and engineers in the field of advanced magnetic materials.

Efforts to address global climate change by developing alternative energy sources and increasing energy efficiency are reliant upon super-strong magnets, in order to efficiently convert mechanical energy to electrical energy. Thus, plans for the integration of wind turbines, wave and tidal energy harvesters and hybrid or electric vehicles into an overall alternative energy strategy are severely impacted by potential shortages of rare earth magnets. It is possible, but not ideal, to substitute existing lower energy-product magnets, such as ferrite or alnico magnets, into these technologies. The sacrifices in performance would be significant.

What is Northeastern's role in researching REEs or their alternatives?

Professor Vincent Harris of the Electrical and Computer Engineering Department is a participant in a Department of Energy program, "High Energy Permanent Magnets for Hybrid Vehicles and Alternative Energy," and I am principal investigator on an Office of Naval Research project, "Rare Earth-Free Permanent Magnets for Advanced Applications." It is anticipated that such efforts will continue in the future.

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