How to recycle the giant magnets inside wind turbines? These scientists have a few ideas.

Every year, hundreds to thousands of megawatts of wind turbines across the United States receive an overhaul. These aging turbines’ rotors are being swapped out, their blades are being replaced and key components such as the generator are being upgraded to improve the machines’ ability to produce electricity from wind. This process is known as “repowering.” Included among the components that are sometimes replaced are magnets made with rare-earth elements such as neodymium and dysprosium, which also play essential roles in smartphones, laptops and electric car motors.

The wide range of applications for rare-earth minerals translates into many possible ways to reuse the constituents of used wind turbine magnets. But today, most of these magnets end up in landfills. It is estimated that less than 1 percent of rare earths is recycled worldwide – from wind turbines, dead hard drivesand everything else.

The US government, fearing a future rare-earth supply crisis what can hold back the energy transition wants to change it. In January, the Department of Energy, or DOE, 20 winners announced of the first phase of its $5.1 million “Wind Turbine Material Recycling Prize.” Funded by the 2021 Bipartisan Infrastructure Act, the prize seeks to develop “a cost-effective and sustainable recycling industry” for wind turbine components that are not commercially recycled today. including wind turbine blades and the super-sized magnets inside some generators. Each of the winning groups receives a $75,000 cash prize to help promote its recycling idea. If a team’s initial results are promising, it could win an additional half-million dollars in cash, as well as a $100,000 voucher for technical assistance from a DOE national laboratory.

The end goal, says Tyler Christoffel, technology manager in the DOE’s Office of Wind Energy Technology, is to bring promising recycling ideas closer to commercialization “on a timeline that will impact the deployment of clean energy and our decarbonization goals.”

Rare earth magnets are the strongest commercial magnets available today. They have a variety of uses, including electric vehicle motors and various types of wind turbine generators. Despite their importance for clean energy, extraction and refining of rare-earth elements is everything but green. Large volumes of earth must be moved to excavate these metals, and harsh chemicals are needed to concentrate and separate them. The environmental impacts of rare-earth mining, along with the expectation that global demand for rare earth minerals will skyrocket in the coming decades, suggests that we should do everything possible to recover rare earths from old technology so that they can be used again. Considering that the generators can contain wind turbines inside hundreds of pounds of rare-earth metals, it seems like a no-brainer for the wind industry to start recycling rare-earth magnets as soon as possible.

But that’s not what happens.

“Right now, to our understanding, essentially no rare earth elements are being recovered from wind,” Christoffel told Grist, citing the immaturity of rare earth recovery technology, the economic challenges associated with scaling up new recycling processes, and the limited amount of used turbine magnets that require recycling today. As the US continues to expand its land-based wind fleet and move offshore, where rare-earth-intensive generators are favoredwill the lack of magnet recycling options “become a much more pressing issue,” he said.

The DOE hopes to prevent this problem through its new recycling price.

Of the 20 teams that won an initial share of prize money last month, four were expressly focused on magnet recovery. Christoffel said these teams were chosen because their recycling solutions seemed novel and promising, and because they demonstrated that they were “capable of advancing the technologies to commercialization.” In addition, most of these groups have proposed cleaner and less energy-intensive alternatives to traditional metal recycling approaches.

“What this prize really helps to do is promote some of these recycling technologies that can provide lower emissions, lower resource use [path] to a magnet,” Christoffel said.

For example, in one process for the recovery of rare-earth magnets it is previously studied, magnet waste is placed in a furnace at elevated temperatures and exposed to hydrogen gas to extract the metals. If the waste has become highly corroded, or oxidizedcalled an additional, emissions-intensive step molten salt electrolysis may be necessary to convert those elements back into a metallic form. A Phase One award-winning team from the University of Utah is pioneering a new approach that relies on chemical reactions involving both hydrogen and magnesium at elevated temperatures to separate neodymium from magnet waste and convert it back into a high- pure metal. This process allows recyclers to bypass molten salt electrolysis, significantly reducing both carbon emissions and energy consumption.

“We showed the response, the concept, work” on a very small scale, project leader Zhigang Fang, a metallurgist at the University of Utah, told Grist. Over the next six months, the team plans to “scale up to a larger quantity so that we can demonstrate … that this is a robust process that has the potential to be scaled up to a production scale.”

In another popular metal recovery approach, hydrometallurgy, recoveries often use strong acids to extract metals from waste. Phase One Award Winner Critical Materials Recycling, Inc. takes a greener spin on this approach with acid-free decomposition recyclinga method developed at Ames National Laboratory in which rare earths are extracted from magnets using a water-based solution.

Critical Materials Recycling’s parent company, TdVib, signed a license agreement for the technology in 2021 and is setting up a pilot plant that uses it to recover rare earth metals from electronic waste. With the DOE’s support, Critical Materials Recycling will now investigate the logistics and economics of establishing a domestic wind turbine magnet recycling industry. Eventually, with additional funding, the company hopes to actually start recycling magnets from turbines on a pilot scale using its technology.

Partnering with the wind industry “seemed like a natural fit” for Critical Materials Recycling, company CEO Daniel Bina said to Grist. Bina noted that Iowa, where the company is headquartered, the second largest wind producer in the nation. “We obviously have to work with those people in our backyard to recover rare earth from materials we have here,” he said.

With phase one of the competition over, teams are now working on theirs phase-two submissions, which includes a prototype demonstration of their technology and a detailed plan to scale it up further. Up to six teams will be eligible to win $500,000 phase two prizes, which the DOE expects to announce in late summer or early fall, Christoffel said.

While the prize competition itself will not result in a brand new recycling industry, the DOE hopes to produce a range of technologies that could serve as the foundation for commercial rare-earth magnet recycling from wind turbines. Currently, there are not a large number of wind turbines that have reached the end of their rating 30 year lifespan. But that will change in the coming decades. Meanwhile, there are some magnets that can be recovered from turbines after repowering, plus additional waste produced during magnet manufacturing.

“Hopefully this kind of competition will bring more attention” to the fact that there are ways to recycle rare-earth magnets from wind turbines, said Linda Wang, who leads another prize-winning team at Purdue University that is developing a low-carbon fabric. , hydrogen-powered rare-earth recycling process. “We have the technology. … The companies that own the wind turbines need to do some long-term planning to take them down, instead of skipping[ping] them to landfills.”