Researchers at the US-based Critical Materials Institute (CMI) at Iowa State University are commercialising an innovative method of recycling rare earth metals by extracting them directly from scrap magnetic batteries.
A big advantage compared to other approaches is that the solution used to dissolve the magnet waste using water rather than acid so it is said to be eco-friendlier and more efficient. The technology developed at CMI, a US Department of Energy innovation hub led by the Ames Laboratory, is being licensed to Iowa-based TdVib, a specialist in magnetically activated smart materials and electromagnetic technologies.
‘We take that shredded mix and we put it in solution that targets the magnets that contain the rare earths and leaves the rest of the components undissolved,’ says Ikenna Nlebedim, CMI’s lead researcher on the recycling project. ‘With the rare earth in solution, we filter off the rest of the e-waste and later pull the rare earths out of the solution. And that’s how we do our recycling. It’s a very efficient and robust process.’
Dan Bina, president and ceo of TdVib, is optimistic that upscaling the process from the lab to a commercial operation will be successful. ‘It is typical for efficiency to decrease during scaling of new processes but we have observed the opposite with the acid-free dissolution process without compromising the purity,’ he says.
‘We have increased the leaching efficiency from around 70% obtained during laboratory research to 90% in our facility. For pre-concentrated magnets the dissolution efficiency can exceed 98%.’
The process begins without acids and by-products are treated to eliminate acid-contaminated wastes, making it friendlier for the environment. Unlike other recycling which involves heating the e-waste to 315 Celsius to demagnetise the magnets, the CMI process does not require pre-heating, meaning lower energy use and less pollution.
‘Acid-free dissolution has all the critical features for sustainable recycling,’ says Denis Prodius, co-inventor of the technology. ‘It is environmentally friendly, has demonstrated its economic potential and efficiently recovers high purity products suitable for commercial applications.’
Since the solution used in this process is copper based, the processed e-scrap ends up infused with copper. This copper can be recovered or reused in other operations. By leaving other materials in the e-scrap intact, it is possible for others to extract metals such as gold and platinum from the leftover materials.