Journal of Sustainable Metallurgy

, Volume 4, Issue 2, pp 163–175 | Cite as

Towards an Alloy Recycling of Nd–Fe–B Permanent Magnets in a Circular Economy

  • Oliver DiehlEmail author
  • Mario Schönfeldt
  • Eva Brouwer
  • Almut Dirks
  • Karsten Rachut
  • Jürgen Gassmann
  • Konrad Güth
  • Alexander Buckow
  • Roland Gauß
  • Rudolf Stauber
  • Oliver Gutfleisch
Innovations in WEEE Recycling
Part of the following topical collections:
  1. Innovations in WEEE Recycling


Rare earth permanent magnets are an integral part of many electrical and electronic devices as well as numerous other applications, including emerging technologies like wind power, electric vehicles, fully automized industrial machines, and robots. Due to their outstanding properties, magnets based on Nd–Fe–B alloys are often not substitutable by employing less critical material systems. Today, WEEE (Waste Electrical and Electronic Equipment) take-back systems for a variety of products containing Nd–Fe–B magnets are well established. They form an ideal basis for a systematic provision of scrap magnets that can be recycled. Hydrometallurgical approaches that aim at completely dissolving the material to regain elements or oxides are energy and time consuming. Thus, they are costly and come with a large environmental footprint. Recycled rare earth elements and oxides would have to compete with virgin materials from China and can hardly be processed in Europe, due to the lack of respective industries. This paper presents material-to-material recycling approaches, which would maintain the magnet alloys and use them directly for a new magnet production loop. The recycled magnets compete well with those made from primary materials, that is, in terms of magnetic properties as well as in terms of production costs. They excel by far rare earth permanent magnets made from primary materials regarding the environmental footprint. Regarding the shift towards a Green Economy, humanity will consume less fuels in combustion processes but rather exploit functional materials in renewable energy and mobility technologies in the future. This shift fundamentally depends on a circular economy of noble as well as less-noble technology metals.


Nd–Fe–B Permanent magnet Rare earth recycling Hydrogen decrepitation Melt-spinning 



The authors would like to thank the Federal Country Hessen for financial support in setting up the Fraunhofer Project Group IWKS. In addition, the authors are thankful to the German Ministry of Education and Research for financial support for project RECVAL-HPM (Innovative Reuse and Recycling Value Chain for High Power Magnets). The authors are grateful to the Fraunhofer Gesellschaft which supports this research by a major project: Lighthouse Project Criticality of Rare Earths. The authors thank David Kennedy for his support and discussion on the cost estimation.The authors also thank Siam Rummel and Konrad Opelt for their experimental assistance and discussion.


Funding was provided by Hessisches Ministerium für Wissenschaft und Kunst, Bundesministerium für Bildung und Forschung and Fraunhofer-Gesellschaft.


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Copyright information

© The Minerals, Metals & Materials Society 2018

Authors and Affiliations

  • Oliver Diehl
    • 1
    Email author
  • Mario Schönfeldt
    • 1
  • Eva Brouwer
    • 1
  • Almut Dirks
    • 1
  • Karsten Rachut
    • 1
  • Jürgen Gassmann
    • 1
  • Konrad Güth
    • 1
  • Alexander Buckow
    • 1
  • Roland Gauß
    • 2
    • 1
  • Rudolf Stauber
    • 1
  • Oliver Gutfleisch
    • 1
    • 3
  1. 1.Fraunhofer ISC, Project Group Materials Recycling and Resource Strategies IWKSHanauGermany
  2. 2.EIT RawMaterials GmbHBerlinGermany
  3. 3.Technische Universität Darmstadt, Materials ScienceDarmstadtGermany

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