A chemical approach to recycling is enabling a WPI professor to extract rare-earth elements from electric and gas hybrid vehicles that have outlived their usefulness.

Rare-earth elements - the 17 elements which are plentiful in the earth but difficult to mine because they are generally not found in large concentrations - must be separated from one another before they can be used for commercial applications such as electric motors, wind turbines and medical imaging devices.

While the United States had done significant work in mining rare-earth elements, China has become the world leader in mining these elements and provides 97 percent of the global supply for manufacturing.

These elements, which include neodymium, dysprosium and praseodymium, have become an integral part of the modern technology. They are the primary reason that technology devices continue to be smaller and lighter than previous models.

Marion Emmert, an assistant professor of chemistry and chemical engineering at WPI, has developed the methodology to recover rare-earth elements from the drive unit of electric cars. She said these elements are valuable to technology: “Because they have a high magnetic density, they are very light, which is great for fuel efficiency.”

Ms. Emmert said the two elements she is most interested in recovering are neodymium and dysprosium.

“The neodymium holds the magnetism, while the dysprosium keeps the magnet stable at high temperatures,” she said.

Ms. Emmert said she was presented with the real-world problem by a General Motors development engineer several years ago.

“There is no way to deal with these motors at the end of their useful life,” Ms. Emmert said. “We were asked to develop a commercially feasible solution.”

She has partnered with WPI’s Center for Resource, Recovery and Recycling and postdoctoral fellow H.M. Dhammika Bandara in researching ways to extract the rare-earth elements from the car’s drive unit.

By demagnetizing the elements, the engine components could be run through a traditional auto shredder. Had the elements not been demagnetized, they would have stuck to the shredder and not been recoverable.

“That was our first innovation,” Ms. Emmert said. “We ended up with a mix of elements, but all we wanted was the rare-earth elements, so we used a mild acid to extract them.”

Once the elements were in the acid solution, Ms. Emmert developed a second reagent that would make the rare-earth elements fall out of the solution as a solid.

“It’s a white powder, with all the elements together,” she said. “Before they can be used, they need to be separated from one another.”

A regular gasoline-powered car has approximately half a kilogram of rare earth elements, she said, while a hybrid electric car has five kilograms, with about half of them in the car’s battery.

“So that’s about five pounds of recoverable material,” she said. “The way we’ve dealt with this is very chemistry-based, which is not often done with recycling, which is probably why it worked.”

WPI has filed a provisional patent on Ms. Emmert’s recovery technology, and the school has begun searching for an investor who will commercialize the process.

“We have developed a commercialization plan and have determined that it can be commercially feasible," she said.