烧结Nd-Fe-B磁体废料回收Nd2O3的方法研究

Research on the Methods of Nd2O3 Recovery from Sintered Nd-Fe-B Magnet Waste

采用硫酸复盐沉淀法、草酸二次沉淀法和磷酸盐沉淀法从烧结Nd-Fe-B废料中回收Nd2O3,先以硫酸或草酸对工业生产的Nd-Fe-B废料进行预处理,钕离子经碱化、酸溶解后,再分别采用草酸或碳酸铵沉淀而与铁分离,最后经煅烧得到Nd2O3粗产品。借助扫描电镜观察Nd2O3粉末形貌,并通过EDTA滴定确定Nd2O3产品的纯度并计算回收率。结果表明,不同方法制取的Nd2O3粗产品纯度和回收率相差较大,Nd2O3纯度为74%~92%,总回收率为24%~29%,粒径为3~200μm,形状不规则,分散性较高,且颗粒表面和内部有很多细孔,多为蓬松状。综合考虑工艺流程的复杂程度以及Nd2O3纯度和回收率,硫酸复盐沉淀法在烧结Nd-Fe-B废料回收Nd2O3的实际应用中较有优势。

Nd2O3 was recovered from the sintered Nd-Fe-B waste with the sulphate double salt precipitation method,the secondary oxalate precipitation method and the phosphate precipitation method.The industrially produced Nd-Fe-B waste was pretreated with sulfuric acid or oxalic acid.After alkalization and acid dissolution,neodymium ions were separated from iron by precipitation with oxalic acid or ammonium carbonate,and finally the crude Nd2O3 product was obtained by calcination.The morphology of Nd2O3 powder was observed by scanning electron microscope,and the purity of Nd2O3 product was determined by EDTA titration and the recovery rate was calculated.The purity and recovery rate of crude Nd2O3 products prepared with different methods are quite different.The purity of Nd2O3 is 74%~92%,the total recovery rate is 24%~29%,and the particle size is 3~200μm.These Nd2O3 products are of irregular shape and relatively high dispersity,and they are multihole and mostly fluffy.Considering the complexity of the process and the purity and recovery rate of Nd2O3,the sulfate double salt precipitation method has advantages in the practical application of Nd2O3 recovery from sintered Nd-Fe-B waste.