Recycling of rare earth earth materials

Recycling of rare earth earth materials
Dr Allan Walton
Magnetic materials group (MMG),
University of Birmingham
Rex Harris, John Speight, Vicky Mann, Richard Sheridan, Malik Degri, Andy
Bradshaw, Jonathan Meakin, Matthew Farr, Enrique Lalana, Christian Jonsson,
Oliver Brooks, Wei Zhou, Alex Campbell, Tarrence Bhatti

ERECON – European Rare Earth
Competency Network
80 European rare earths experts from industry, academia,
and the policy world
Under the guidance of a high-level Steering Committee,
three working groups have examined challenges and
solutions for -
(1) Mining rare earths in Europe,
(2) Recycling and substituting rare earths
(3) Fostering new business models for creating a more
resilient, competitive, and sustainable European rare
earths supply chain

Working group 2 - Recycling
of Rare Earths
The aims for working group 2 were as follows –
• To identify the potential for recycling of rare earths in the EU.
• To identify barriers to recycling of rare earths.
• To prioritise rare earth sectors where recycling should be
targeted.
• To identify products within these sectors where recycling
could be applied more easily.
• To identify technology gaps for recycling of rare earths within
the EU.
• To produce a list of recommendations for the EU to promote
recycling of rare earth materials .

What are the advantages
of a recycled source of rare earths
• It would be possible to target the most critical rare earths and
address the balance problem.
• A recycled source will not contain radioactive material
• The time to market for a recycled source is likely to be shorter
than a primary mined source in the EU.
• A lower environmental footprint.
• The potential for all the steps to be performed in the EU
• The EU has one of if not the most advanced recycling industries
in the world. Huge potential to innovate

Magnets and Phosphors were
identified as a priority.
Priority list for
rare earth
magnets
1) Hard disk drives, DVD and CD players
2) Automotive applications
3) Motors in industrial applications
4) Loudspeakers
5) Air conditioning compressors
6) Magnetic separators
7) Mixed electronics
8) Electric bicycles
9) Wind turbines

Examples of barriers for recycling
• The urban mine is not fully understood for rare earths
• Insufficient and non targeted collection
• Separation of rare earths from the waste stream is often
difficult due to small amounts of material, coatings,
complicated architectures etc…
• Re-processing technologies have to be optimised for a
recycled source with a range of compositions and impurities.
• In the current policy framework a recycled source has
to be cheaper than primary production from China

Examples of technical barriers
to recycling of rare earth
magnets

Separation of NdFeB from
the waste stream
screw
Spindle motor
containing resin
bonded NdFeB
magnet
Disk
Casing
Voice
Coil
Motor
Photograph of
shredded hard disk
drives. Walton et al.
HDD
Screws
Voice Coil
Assembly
Computer hard disk drive
Sintered
NdFeB
Magnet

Barriers – Compositional variations
of magnets in scrap
Dy content (wt%) of sintered NdFeB magnets from HDDs (voice coil) as a
function of year and manufacturer (each symbol type represents one
manufacturer).
HDD’s provided by Stena Technoworld AB, ICP analysis performed at Leitat
Technology Centre Barcelona as part of the EU Framework 7 project Remanence.

The use of hydrogen to process HDDs

Separation of NdFeB from VCM
Ni electroplate
Soft magnetic
Fe casing
Hydrided
NdFeB
powder
Voice coil assembly
extracted from hard
drive
Voice coil assembly after
Hydrogen processing.
Ni electroless plated
voice coil magnet

Prototype reactor for separating NdFeB magnets from WEEE
Hard disk drives loaded into porous drum
Figure . Hard disk drives loaded within the tumbling
stage
Hydrogen vessel
Valve set
Collection
vessel
Porous rotating stage inside vessel

Extracted powders
Material extracted from
tumbling stage (10
sectioned HDDs).
Optical micrograph of a
cross section through a
HD processed sintered
NdFeB magnet particle
The Ni content of the extracted powders for
5kg of material was around 400ppm after
sieving to 90 microns
Sieving with ball
bearings has been used
to preferentially break
down the NdFeB
compared to the Ni and
other impurities

Options for re-processing

Re-processing routes for
rare earth magnets
Source: Roland Gauß, Oliver Diehl, Oliver Gutfleisch,
Fraunhofer Project Group IWKS.

Key recommendations
• Map the urban mine to assess the potential for recycling
• Design for recycle
• Modify waste directives to take into account the critical materials
• Schemes to improve collection rates eg – incentives.
• R&D and pilot plant development to improve the detection,
separation and purification of rare earth materials from waste
streams.
• R&D and pilot plant development on re-processing technologies –
eg- hydrometallurgy, pyrometallurgy,re-sintering, HDDR etc….

(Rare Earth Magnet Recovery for Environmental and Resource Protection)
The organisations involved in the consortium are:
• C-Tech Innovation Ltd,
• The University of Birmingham,
• Stena Technoworld AB,
• ACREO Swedish ICT AB,
• Leitat Technological Centre,
• OptiSort AB,
• Chalmers Industriteknik,
• Magneti Ljubljana,
• Kolektor Magnet Technology GMBH.
Partner in an ITN Training network EREAN run by Koen Binnemans
(Leuven).

Acknowledgements
HyProMS (TSB project in the UK (2008-2010)) : Hydrogen Processed Magnet Scrap
Partners - PowdermatriX (Project Managers),Secure IT Recycling Ltd, Less Common Metals
Ltd, Magnet Applications Ltd, Precision Magnetics Ltd, Birmag Ltd, Arnold Magnetics.
Publications –
A.walton, I.R.Harris, A.J.Williams – REPM 2012
R.S. Sheridan, A.J. Williams, I.R. Harris, A. Walton – REPM 2012.
A.Walton, A.J.Williams – Materials World – August 2011
A.Walton, A.J.Williams – Recycling International, May 2011
M. Zakotnik et al, I.R.Harris, A.J.Wiliams. - Journal of Alloys and Compounds 469 (2009)
314–321.
M. Zakotnik, I.R.Harris, A.J.Williams - Proceedings of 19th International Workshop on Rare
Earth Permanent Magnets & Their Applications (2006)
M. Zakotnik, A.J. Williams and I.R. Harris - Proceedings of 18th International Workshop on
Rare Earth Permanent Magnets & Their Applications (2004)
US patent – No.13/169839
Contact details –
Dr Allan Walton a.walton@bham.ac.uk , 0121 414 5195, www.magnets.bham.ac.uk

Mining
Refining
Hydrogen
Decrepitation
Cast Alloy
HD Powder
Hydrogen Recycled
NdFeB
powder
Jet Milling
HDDR
Processing
Mix with
epoxy
resin and
press into
bonded
magnets
Mix with
epoxy
resin and
press into
bonded
magnets
Degas /
Press
Melt Spin
Aligning & Pressing
Vacuum Sintering
Mix with resin and press into
bonded magnets