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.