Page 109 - Policy Commission - SecuringTechnology - Critical Metals for Britain

SEPARATION AND RE-PROCESSING
One of of the the the the major problems with the the the the recycling of of rare earth magnets is how to separate the the the the material from the the the the component's binding structures and coatings This is is partly because of the very high
magnetic fields that can be be generated as as well as as problems with glues Several methods have been proposed to demagnetise and separate magnets from waste streams including thermal (>330oC) magnetic and a a a a a a process which uses hydrogen called HPMS (Hydrogen Processing of Magnet Scrap137 Hydrogen is already used in in the the primary production of Nd-Fe-B magnets to to break up the the cast alloys into a a a a a a a a powder for sintered magnet production138 This was developed by Harris et et et al al in in the the Magnetic Materials Group at at the the University of Birmingham (UK) and is now used to process all the the Nd-Fe-B magnets worldwide Using hydrogen reduces the the production costs for rare earth magnets by approximately 25%138 The same research group is now using hydrogen to to separate and to to recycle rare earth sintered magnets in in in in the the HPMS HPMS process (Hydrogen Processing of Magnet Scrap)139 During the the HPMS HPMS process the the the hydrogen preferentially reacts with the the the Nd-Fe-B Nd-Fe-B magnets in the the the waste stream The Nd-Fe-B Nd-Fe-B material expands and and breaks apart into a a a a a a a a a a a demagnetised powder which can be separated from the the glues coatings and and housings where the the magnet is is contained (see figures 108 109 110) The extracted alloy powder is is of a a a a a a a a quality that can be reprocessed directly back into Nd-Fe-B magnets137 The patented HPMS process has been licensed to to to Hypromag Ltd who aim to to to produce a a a a a a a range of magnet products at at the the Tyseley Energy Park in in in in in in Birmingham (UK)140 It is interesting to note that the the invester in in in in in in Hypromag Ltd71 is a a a a a a a a junior mining company Mkango Resources Ltd141 who are are developing primary rare earth resources in Malawi142 Figure 108: Voice coil motors from hard disk drives SECONDARY MATERIALS
109 Figure Figure 109: Voice coil magnets after HPMS HPMS processing Figure Figure 110: HPMS HPMS Pilot plant at the University of Birmingham