Researchers from the University of Jyväskylä, Finland, have developed a solid-phase extraction process that enables the eco-friendly recovery of critical raw materials from NdFeB magnets. The developed method utilizes organic methanesulfonic acid, which is a greener option for traditional inorganic acids. The developed process proved to be highly effective, and it was also patented.
Rare earth elements are critical raw materials. In particular, the demand for neodymium has significantly increased. Neodymium is utilized in data centers and in permanent magnets for electric vehicles and wind turbines.
China dominates the primary production of rare earth metals, which has increased geopolitical risks related to these raw materials. The geopolitical risks combined with rapidly growing demand and low recycling rates, has encouraged researchers to develop new recovery solutions for rare earth elements from secondary sources, for example, from discarded permanent magnets and magnetic waste.
- Currently, only one percent of the rare earth elements used in the European Union are recycled. The low recycling rate can be partly explained by the fact that current recycling methods are not economically viable. The need for new methods is therefore clear, emphasizes Assistant Professor Jani Moilanen from the University of Jyväskylä, who led the research together with Professor of Chemical Circular Economy Ari Väisänen from the University of Jyväskylä.
A simple and environmentally friendly solution
The recently developed process was designed to be as simple as possible and to be based on benign chemicals.
- We were able to use the same organic methanesulfonic acid in dissolving and recovering steps, which minimized the use of different acids in the recovery process. In addition, the process required only two other low-risk aqueous solutions to recover other raw materials, such as cobalt, from the permanent magnet, explains Postdoctoral Researcher Emilia Virtanen from the University of Jyväskylä, who was involved in the research.
More than 96% recovery and high purity
The developed process proved to be extremely effective in recovering rare earth elements. Over 96% of the rare earth elements in the permanent magnets were recovered, and the purity of the rare earth fraction was over 99%.
In addition to the process development, the 3D-printed filters used in solid-phase extraction were also studied using various methods. The study combined the Department of Chemistry’s strong expertise in spectroscopy with the Department of Physics’ expertise in X-ray tomography. Through this collaboration, it was possible to examine the structure of the filters in detail even at the nanoscale.
- Using tomography, we obtained detailed information on the micro level structures of 3D-printed filters. Based on these results, we were able to determine what kinds of structural changes occur in the filters during extraction processes. Based on the measurements, the filters seem to be very robust and suitable for industrial use, says Postdoctoral Researcher Janne Yliharju from the University of Jyväskylä, who performed the tomography part.
- Measurements using scanning near-field optical microscopy, revealed that the active substance in the filters was clearly separated from the nylon-based host matrix. This structure enables the efficient recovery of critical raw materials, adds Staff Scientist Eero Hulkko from the University of Jyväskylä.
Professor Mika Lastusaari’s research group from the University of Turku also participated in the project. The research group performed additional measurements on the filters. The research was funded by the Technology Industry 100th Anniversary Foundation, the Jane and Aatos Erkko Foundation, and the Academy of Finland.