A facile process to optimize performance of regenerated Nd-Fe-B sintered magnets:Chemo-selective dissolution washing  

作　　者：Haibo Xu Qingmei Lu Lichao Yu Liying Cong Haowen Tian Weiqiang Liu Youhao Liu Yunqiao Wang Jingwu Chen Xiaofei Yi Qiong Wu Ming Yue 

机构地区：[1]College of Materials Science&Engineering,Key Lab of Advanced Functional Materials,Beijing University of Technology,Beijing,100124,China [2]Ganjiang Innovation Academy,Chinese Academy of Sciences,Ganzhou,341119,China [3]State Key Laboratory of Rare Earth Permanent Magnetic Materials,Hefei,231500,China [4]Earth-Panda Advanced Magnetic Materials Co.,Ltd.,Hefei,231500,China [5]Beijing Zhong Ke San Huan Research,Beijing,102200,China

出　　处：《Journal of Rare Earths》2023年第12期1976-1983,I0006,共9页稀土学报（英文版）

基　　金：Project supported by the National Key R&D Program of China (2021YFB3500801);the National Natural Science Foundation of China(52271161);the Science and Technology Program of Anhui Province(201903a07020002);General Program of Science and Technology Development Project of Beijing Municipal Education Commission (KM202010005009);"QiHang Programme"for Faculty of Materials and Manufacturing,BJUT (QH202211);Program of Top Disciplines Construction in Beijing (PXM2019_014204_500031);Key Laboratory of Ionic Rare Earth Resources and Environment,Ministry of Natural Resources of the People’s Republic of China (2022IRERE302);the State Key Laboratory of Rare Earth Permanent Magnetic Materials Opening Foundation(SKLREPM170F02)。

摘　　要：In this work,the recycled Nd-Fe-B powders and regenerated Nd-Fe-B sintered magnets with low impurity content were successfully prepared from Nd-Fe-B magnet sludge via reduction diffusion(RD)method followed by a chemo-selective dissolution washing proc ess.The chemo-selective dissolution effect of various solution(deionized water,dilute acetic acid solution,NH_(4)Cl-methanol solution) was evaluated by impurity content and magnetic properties of the recycled Nd-Fe-B powder.The NH_(4)Cl-methanol solution can selectively remove impurities with minimal damage to the magnetic phase.Besides,the optimal NH_(4)Cl concentration and liquid-to-solid ratio were investigated.As a consequence,the contents of Ca,O,and H after optimal washing process are reduced to 0.07 wt%,0.31 wt% and 0.22 wt%,respectively.Hence,M_(3) Tis increased to 146.72 emu/g,which is 33% higher than that of the initial sludge.Then,the regenerated Nd-Fe-B sintered magnets with properties of B_(r)=11.66 kG,H_(cj)=16.49 kOe,and(BH)_(m)=31.78 MGOe were successfully prepared by mixing with 40 wt% Nd4Fe14B alloy powders.Compared with the corresponding regenerated magnets washed with deionized water,the remanence and coercivity are increased by 18% and 59%,respectively.

关 键 词：Recycling Nd-Fe-B magnet Sludge Chemo-selective dissolution Washing process Magnetic properties Reduction diffusion Rare earths 

分 类 号：TB34[一般工业技术—材料科学与工程]