Recycling of rare earth sintered magnets as isotropic bonded magnets by melt-spinning

Multiple recycling of NdFeB-type sintered magnets

“…Burns et al used the HD process and out-gassing to produce coercive powders from hot deformed ingot material [3]. Sintered magnets were recycled by Itoh et al using Ca metal reduction followed by a melt spinning technique and this material was used to produce isotropic bonded magnets [4,5]. These workers also made a microwave absorber by converting a sludge powder (generated by cutting and polishing NdFeB magnets) by means of a hydrogenation and disproportionation process followed by oxidation to give an ␣-Fe/rare earth oxide.…”

Recycling of scrap sintered Nd–Fe–B magnets as anisotropic bonded magnets via hydrogen decrepitation process

“…Takeda [3] investigated the possibility of extracting Nd metal directly from magnet scrap. Itoh [4] recycled rare earth containing sintered magnets to make isotropic bonded magnets by melt spinning, and the values of recycling magnets were nearly comparable to the commercially available MQPB bonded magnet. Kwon [5] studied on recycling sintered magnet scrap to prepare bonded magnet powders by adding several rare earth oxide and fluoride after HD process.…”

Verfahren zum Recycling von seltenerdhaltigen Permanentmagneten

“…Kunststoffgebundene Magnete bieten den Vorteil, dass sie in nahezu beliebiger Form erzeugt werden können, liegen allerdings mit Energieprodukten zwischen 5 und 10 MGOe (~40 -80 kJ m -3 ) (bei typischen Pulveranteilen von 60 -80 Vol.-%) in der Energiedichte weit ab von gesinterten Magneten [11]. Auch aus mit Nickel beschichteten Sintermagneten wurden bereits via Melt-Spinning kunststoffgebundene Magnete hergestellt, die Energiedichten bis 11 MGOe (~88 kJ m -3 ) erreichten [28].…”