The environmental and economic recovery of rare-earth (RE) from NdFeB magnet waste is becoming increasingly important. In this study, the sulfurization possibility of two main RE-bearing phases of Nd₂O₃ and NdFeO₃ in the fully oxidized NdFeB waste by ferric sulfate was evaluated. TG-DTA curves of the Nd₂O₃ and NdFeO₃ sulfurization with 1.5 times of the theoretical Fe₂(SO₄)₃·5H₂O dosage showed that the temperatures range of Nd₂(SO₄)₃ formation were 873 K to 963 K, and the starting temperature of Nd₂(SO₄)₃ decomposition was ~ 1070 K. Specific experiments revealed by XRD and SEM-EDS analysis that Nd₂O₃ and NdFeO₃ phases were successfully sulfated by Fe₂(SO₄)₃·5H₂O. The optimum roasting temperature was determined to be 973 K corresponding to the highest Nd leaching efficiency by the sulfurization of Nd₂O₃. At above 973 K, the decomposition of Nd₂(SO₄)₃ resulted in the decrease of Nd leaching efficiency. Furthermore, the required roasting time and Fe₂(SO₄)₃·5H₂O dosage to obtain the same Nd leaching efficiency were different for the sulfurization of Nd₂O₃ and NdFeO₃ at 973 K, and the sulfurization of NdFeO₃ was more difficult than that of Nd₂O₃. Based on the results, an innovative method for recovering RE from NdFeB magnet waste was proposed.

从NdFeB磁铁废料中回收稀土（RE）的环境和经济问题变得越来越重要。在这项研究中，评估了被硫酸铁完全氧化的NdFeB废料中Nd ₂ O ₃和NdFeO ₃的两个主要含稀土相的硫化可能性。用理论Fe ₂（SO ₄）₃ ·5H ₂ O理论用量的1.5倍硫化Nd ₂ O ₃和NdFeO _3的TG-DTA曲线表明，Nd ₂（SO ₄）₃形成的温度范围为873K。 963 K，Nd的起始温度₂（SO ₄）₃分解约为1070K。XRD和SEM-EDS分析表明，通过Fe ₂（SO ₄）₃ ·5H ₂ O成功地硫酸化了Nd ₂ O ₃和NdFeO ₃相。通过Nd ₂ O ₃的硫化确定最高温度为973 K，对应于最高的Nd浸出效率。在973 K以上，Nd ₂（SO ₄）₃的分解导致Nd浸出效率降低。此外，所需的焙烧时间和铁₂（SO ₄）₃ ·5H ₂ ö剂量获得相同的Nd浸出效率为Nd组成的硫化是不同的₂ ö ₃和NdFeO ₃在973 K，和NdFeO的硫化₃比的钕更难₂ ö ₃。在此基础上，提出了一种从钕铁硼磁体废料中回收稀土的创新方法。