Abstract: The present invention is a method of recovering neodymium (Nd) from waste by-products of rare earth magnet manufacture. Two main waste by-products, NdFeB swarf and NdFeB slag, are treated by two respective chemical schemes as described above. However, the only major consumption of chemical compound in both schemes is hydrofluoric acid (HF). The present invention scheme for NdFeB swarf recovery is characterized by using acetic acid (HC.sub.2 H.sub.3 O.sub.2) having a pK value of approximately 4.7. The present invention scheme for NdFeB slag recovery is characterized by using sulfamic acid electrolyte bath having a pH value of approximately 2.7. The moist neodymium trifluoride (NdF.sub.3) produced by both schemes can be dried by using the same microwave radiation technique to produce dry neodymium trifluoride (NdF.sub.3) which contains less than 3% moisture.

Abstract: The present invention is a method of recovering neodymium (Nd) from waste by-products of rare earth magnet manufacture. Two main waste by-products, NdFeB swarf and NdFeB slag, are treated by two respective chemical schemes as described above. However, the only major consumption of chemical compound in both schemes is hydrofluoric acid (HF). The present invention scheme for NdFeB swarf recovery is characterized by using acetic acid (HC.sub.2 H.sub.3 O.sub.2) having a pK value of approximately 4.7. The present invention scheme for NdFeB slag recovery is characterized by using sulfamic acid electrolyte bath having a pH value of approximately 2.7. The moist neodymium trifluoride (NdF.sub.3) produced by both schemes can be dried by using the same microwave radiation technique to produce dry neodymium trifluoride (NdF.sub.3) which contains less than 3% moisture.