Recycle for Sludge Scrap of Nd-Fe-B Sintered Magnet as Isotropic Bonded Magnet
来源期刊：JOURNAL OF RARE EARTHS2004年第1期
论文作者：Masahiro Masuda Shunji Suzuki Masahiro Itoh Ken-ichi Machida
Key words：Nd-Fe-B sintered magnet; recycling; isotropic Nd-Fe-B bonded magnet; melt-spinning method; sludge scrap; rare earths;
Abstract: The reduction diffusion method was performed for the sludge scrap of Nd-Fe-B sintered magnets with adding Ca metal to recover the oxidized Nd-Fe-B phase. After washing the resultant powders to remove Ca metal component, the powders obtained were recycled as an isotropic magnetic powder by the melt spinning method. The magnetic properties of powders as recycled were inferior, especially for the coercivity value, due to the deletion of rare earth metals during the washing process. The adjustment of metal composition, i.e., the addition of Nd metal, at the melt spinning process improved the magnetic properties to be Br=～0.75 T, Hcj=～0.93 mA·m-1, and(BH)max=～91 kJ·m-3. The magnetic properties of the bonded magnets prepared from the composition-adjusted powders were Br=～0.66 T, Hcj=～0.92 mA·m-1, and(BH)max=～70 kJ·m-3, which are approximately comparable to the commercially available MQPB boned one(Br=～0.73 T, Hcj=～0.79 mA·m-1, and(BH)max=～86 kJ·m-3).
Masahiro Masuda1，Shunji Suzuki1，Masahiro Itoh1，Ken-ichi Machida1
(1.Collaborative Research Center for Advanced Science and Technology, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871)
Abstract:The reduction diffusion method was performed for the sludge scrap of Nd-Fe-B sintered magnets with adding Ca metal to recover the oxidized Nd-Fe-B phase. After washing the resultant powders to remove Ca metal component, the powders obtained were recycled as an isotropic magnetic powder by the melt spinning method. The magnetic properties of powders as recycled were inferior, especially for the coercivity value, due to the deletion of rare earth metals during the washing process. The adjustment of metal composition, i.e., the addition of Nd metal, at the melt spinning process improved the magnetic properties to be Br=～0.75 T, Hcj=～0.93 mA·m-1, and(BH)max=～91 kJ·m-3. The magnetic properties of the bonded magnets prepared from the composition-adjusted powders were Br=～0.66 T, Hcj=～0.92 mA·m-1, and(BH)max=～70 kJ·m-3, which are approximately comparable to the commercially available MQPB boned one(Br=～0.73 T, Hcj=～0.79 mA·m-1, and(BH)max=～86 kJ·m-3).
Key words:Nd-Fe-B sintered magnet; recycling; isotropic Nd-Fe-B bonded magnet; melt-spinning method; sludge scrap; rare earths;
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