Rare Earth Exchanges

Green and Sustainable Rare Earth Element Recycling and Reuse from End-of-Life Permanent Magnets

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Highlights

  • Novel microwave and mechanochemical methods offer more efficient and environmentally friendly rare earth element recycling from permanent magnets.
  • Emerging techniques demonstrate lower energy consumption, reduced chemical use, and improved REE recovery rates compared to traditional extraction methods.
  • Potential applications include renewable energy, electronics, and sustainable manufacturing, with promising environmental and technological benefits.

Research and development scientists from Bulgaria and Romania hypothesize that novel, environmentally friendly methods like microwave processing and mechanochemistry can significantly improve the recycling efficiency of rare earth elements (REEs) from end-of-life (EoL) permanent magnets, offering a sustainable alternative to traditional extraction techniques.

The study was designed to evaluate and propose advanced recycling methods, focusing on microwave treatment and mechanochemical processes for recovering REEs from NdFeB magnets.

The study methodology employed several elements, starting with a comparison of conventional recycling methods (hydrometallurgical and pyrometallurgical) with emerging techniques.

Next, the team used laboratory experiments to assess energy efficiency, environmental impact, and recovery rates of REEs. In addition, the team analyzed microwave absorption and mechanochemical activation for recycling efficiency.

Finally, they examined reuse and redesign possibilities for REE-based magnets, including additive manufacturing.

Findings

The Eastern European-based team reports first that microwave technology efficiently removes coatings and recovers REEs by utilizing concentrated energy and reducing processing times.

Particularly effective for oxidized EoL magnets due to their better microwave absorption properties, this process based on this preliminary laboratory work significantly lowers energy consumption and reduces environmental impact compared to traditional methods.

What about the mechanochemistry arm of the study?  It turns out this method achieves high recovery rates of REEs with solvent-free processing, reducing chemical use and emissions. Enabling one-pot or one-step processing, simplifying the recycling workflow. Produces fine NdFeB powders suitable for redesign and reuse in new magnets.

Environmental benefits are reported by the authors. Recycling has a significantly lower carbon footprint than primary REE extraction, an important data point. Also recycled magnets often exhibit better magnetic performance and microstructure than virgin materials.

What were some challenges and assumptions?

While the above outcomes are promising, the authors did encounter some challenges. For example, they report oxidation of REE materials during processing. Additionally, they struggled with the standardization of recycling methods for diverse magnet shapes and compositions.

Will  Microwave and mechanochemical techniques scale efficiently without major losses in recovery rates?  Are present results representative of broader applications across different types of NdFeB magnets?

Limitations

Rare Earth Exchanges summarizes a few of the top limitations to this study:

  • Scale: Most processes are still in the experimental or pilot stages, requiring further validation for industrial-scale implementation.
  • Complexity: Magnet designs vary widely, complicating the standardization of recycling techniques.
  • Economic Viability: While environmentally superior, some methods may face higher initial costs or logistical challenges compared to conventional methods.

Assumptions and Biases

Focus on emerging methods may overlook improvements in conventional recycling technologies.  Additionally, there has been limited evaluation of potential economic barriers and industrial adoption.

Real-World Applications

  • Renewable Energy: Recycled magnets can support wind turbines and electric vehicles, essential for achieving climate neutrality.
  • Electronics and Defense: Recovered REEs can be reused in high-tech applications like aerospace equipment and electronic devices.
  • Sustainable Manufacturing: Recycled NdFeB powders can be integrated into additive manufacturing, reducing waste and resource dependency.

Lead Authors and Academic Organizations

  • Zara Cherkezova-Zheleva (Institute of Catalysis, Bulgarian Academy of Sciences, Bulgaria) – Lead researcher in material recycling and catalysis.
  • Marian Burada, Anca Elena Sobetkii, Sabina Andreea Fironda, Radu-Robert Piticescu (National R&D Institute for Non-Ferrous and Rare Metals, Romania) – Focus on rare earth metals and sustainable technologies.
  • Daniela Paneva (Institute of Catalysis, Bulgarian Academy of Sciences, Bulgaria) – Expert in green chemistry and environmental impact assessment.

Conclusion

This paper highlights microwave processing and mechanochemistry as promising, sustainable alternatives for recycling REEs from EoL magnets. These methods offer potential for scalable, eco-friendly applications in renewable energy and electronics, but further research is required to address challenges related to industrial adoption and economic feasibility.

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