Fundamental Study on Multistage Extraction Using TDdDGA for Separation of Lanthanides Present in Nd Magnets

The separation of Dy from Nd has been studied from the viewpoint of recycling Dy from Nd magnets. N,N,N′,N′-tetradodecyl-DGA (TDdDGA) has a relatively high separation factor between Dy and Nd (above 10) in HNO3 medium. After basic research on batchwise multistage extractions using eight extraction stages with 0.1 M TDdDGA in n-dodecane as organic phase, ten stages with an aqueous phase (0.7 M HNO3 with metals), and six stages with another aqueous phase (0.7 M HNO3 without metals), approximately 99% of Dy was recovered into the organic phase with 1% coextraction of Nd.