Stepwise chlorination-chemical vapor transport reaction for rare earth oxide mixtures Gd2O3-Tb4O7, Tb4O7-Dy2O3 and Dy2O3-Ho2O3

Abstract Stepwise chlorination–chemical vapor transport (SC–CVT) reaction has been investigated for the rare earth oxide mixtures Gd 2 O 3 –Tb 4 O 7 , Tb 4 O 7 –Dy 2 O 3 and Dy 2 O 3 –Ho 2 O 3 mediated by vapor complexes LnAl n Cl 3 n +3 (where Ln=rare earth elements). The results show selective deposition of lighter elements at higher temperatures. The separation factors are 5.84 for Gd/Tb, 3.72 for Tb/Dy and 3.13 for Ho/Dy when using CO as the CVT carrier gas. A combination of enhanced separation factor with reduced total transport yield is also observed for the Tb 4 O 7 –Dy 2 O 3 system when using argon as the CVT carrier gas.