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.
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)。