The structural and magnetic properties were studied for recycling Nd-Fe-B powders from Nd-Fe-B sintered magnets sludge via reduction diffusion(RD)with calcium hydride(CaH2)particles.For com-parison,traditional reducing agent calcium granules were applied to prepare recycled Nd-Fe-B pow-ders.Finer particle size and better size distribution as well as lower impurity content are achieved by using CaH2 instead of Ca.In detail,the average particle size of the recycled Nd-Fe-B powder is reduced from 4.66 to 3.43 pm,and the bimodal distribution disappears.Moreover,the residual calcium content and oxygen content are reduced to about 0.080 wt％and 0.32 wt％.As a consequence,the room-temperature magnetization of the CaH2-recycled Nd-Fe-B powder is increased to 146.30 emu/g,6.8％and 33％,respectively,higher than that of Ca-reduced powder and the initial sludge.Further analysis indicates that CaH2 is able to reduce the sludge at lower temperature to fabricate well-dispersed,uniform recycled powder with high magnetization arising from a combination factors of its low melting point,low thermodynamic behavior,and the release of hydrogen during the reaction.

Haibo Xu;Qingmei Lu;Liying Cong;Haowen Tian;Weiqiang Liu;Youhao Liu;Yunqiao Wang;Jingwu Chen;Xiaofei Yi;Ming Yue

Key Lab of Advanced Functional Materials,Ministry of Education,Faculty of Materials and Manufacturing.Beijing University of Technology,Beijing 100124,China;State Key Laboratory of Rare Earth Permanent Magnetic Materials,Hefei 231500,China;Earth-Panda Advanced Magnetic Materials Co.,Ltd.,Hefei 231500,China;Beijing Zhong Ke San Huan Research,Beijing 102200,China

稀土学报（英文版）

[1]Haibo Xu;Qingmei Lu;Liying Cong;Haowen Tian;Weiqiang Liu;Youhao Liu;Yunqiao Wang;Jingwu Chen;Xiaofei Yi;Ming Yue-.Calcium hydride reduced high-quality Nd-Fe-B powder from Nd-Fe-B sintered magnet sludge)[J].稀土学报（英文版）,2022(12):1905-1912

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