摘要: The optimum conditions for extraction chromatography using 2ethyl-hexyl 2-ethylhexylphosphonate resin to separate thulium, yetterbium and luticium were studied. According to the proposed procedure, several grams of yetterbium oxide （purity = 99.95%） and luticium oxide （purity = 99.90%） were separated from the mixed heavy rare earth oxides on laboratory scale. Their relatively high recoveries （99% and 95% for Yb₂O₃ and Lu₂O₃ respectively） may be satisfactory.