REE Recovery from End-of-Life NdFeB Permanent Magnet Scrap: A Critical Review
REE Recovery from End-of-Life NdFeB Permanent Magnet Scrap: A Critical Review
Yongxiang Yang 0 1 2 3 4 5 6
Allan Walton 0 1 2 3 4 5 6
Richard Sheridan 0 1 2 3 4 5 6
Konrad Gu¨ th 0 1 2 3 4 5 6
Roland Gauß 0 1 2 3 4 5 6
Oliver Gutfleisch 0 1 2 3 4 5 6
Matthias Buchert 0 1 2 3 4 5 6
Britt-Marie Steenari 0 1 2 3 4 5 6
Tom Van Gerven 0 1 2 3 4 5 6
Peter Tom Jones 0 1 2 3 4 5 6
Koen Binnemans 0 1 2 3 4 5 6
0 Fraunhofer ISC, Project Group IWKS , Rodenbacher Chaussee 4, 63457 Hanau , Germany
1 School of Metallurgy and Materials, University of Birmingham , Edgbaston, Birmingham B15 2TT , UK
2 Department of Materials Science and Engineering, Delft University of Technology , Mekelweg 2, 2628 CD Delft , The Netherlands
3 Department of Materials Engineering, KU Leuven , Kasteelpark Arenberg 44, Box 2450, 3001 Leuven , Belgium
4 Department of Chemistry and Chemical Engineering, Chalmers University of Technology , 412 96 Go ̈teborg , Sweden
5 Resources & Transport Division, O ̈ ko-Institut e.V. , Rheinstraße 95, 64295 Darmstadt , Germany
6 Institute of Material Science, Technische Universita ̈t Darmstadt , Alarich-Weiss-Str. 16, 64287 Darmstadt , Germany
NdFeB permanent magnets have different life cycles, depending on the applications: from as short as 2-3 years in consumer electronics to 20-30 years in wind turbines. The size of the magnets ranges from less than 1 g in small consumer electronics to about 1 kg in electric vehicles (EVs) and hybrid and electric vehicles (HEVs), and can be as large as 1000-2000 kg in the generators of modern wind turbines. NdFeB permanent magnets contain about 31-32 wt% of rare-earth elements (REEs). Recycling of REEs contained in this type of magnets from the End-of-Life (EOL) products will play an important and complementary role in the total supply of REEs in the future. However, collection and recovery of the magnets from small consumer electronics imposes great social and technological challenges. This paper gives an overview of the sources of NdFeB permanent magnets related to their applications, followed by a summary of the various available technologies to recover the REEs from these magnets, including physical processing and separation, direct alloy production, and metallurgical extraction and recovery. At present, no commercial operation has been identified for recycling the EOL NdFeB permanent magnets and the recovery of the associated REE content. Most of the processing methods are still at various research and development stages. It is estimated that in the coming 10-15 years, the recycled REEs from EOL permanent magnets will play a significant role in the total REE supply in the magnet sector, provided that efficient technologies will be developed and implemented in practice.
Critical raw materials; Neodymium; Rare earths; Rare-earth magnets; Recycling; Urban mining
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Neodymium–iron–boron (Nd2Fe14B, or NdFeB for short)
permanent magnets are considered as the best available
magnets since their introduction on the market in 1984, due
to their superior energy product (with a theoretical
maximum of 512 kJ/m3), which makes them highly efficient and
suitable for lightweight mobile applications [1].
Consequently, they are widely used in wind turbines,
hybrid and electric vehicles (HEVs and EVs), household
electrical appliances, computer hard disk drives (HDDs),
and many small consumer electronic devices.
NdFeB permanent magnets have different life cycles,
depending on the applications: from as short as 2–3 years
in consumer electronics to 20–30 years in wind turbines.
The weights of the magnets range from less than 1 g in
small consumer electronics to over 1 kg in EVs and HEVs,
and can be as large as 1000–2000 kg in the generators of
modern wind turbines. NdFeB magnet contains about
31–32 wt% rare-earth elements (REEs), mainly Nd ? Pr
plus a few minor, but expensive, heavy rare-earth elements
(HREEs) such as Dy, Tb, and Gd, depending on the
applications. Recycling of REEs contained in this type of
magnets from the End-of-Life (EOL) products will play an
important and complementary role for the primary supply
of REEs in the future. However, collection and recovery of
the magnets from small consumer electronics imposes
great social and technological challenges. At present, no
mature and economically feasible technologies have been
identified for recycling the EOL NdFeB permanent
magnets and the recovery of the associated REEs. Most of the
processing methods are still at the research and
development stage. It is estimated that from 2030 on, the recycled
REEs from the EOL permanent magnets will play a
significant role in the total REE supply in the magnet sector
[2]. Moreover, recycling of REEs is also of importance for
the so-called Balance Problem, since it avoids producing
excesses of La or Ce while mining of REE ores for Nd and/
or Dy production [3–5].
To date, no commercial process to recycle these REEs
from EOL products is operational. It is simply cheaper to
buy REE maste (...truncated)