Published online by Cambridge University Press: 25 February 2011
Lanthanum chloride was synthesized by reacting La2O3 with CCl4. Purification carried out by zone refining resulted in reduction of Nd and Eu concentrations by at least a factor of 103. Impurity segregation coefficients were calculated from the concentration profiles in the charge measured by neutron activation analysis. Values of 0.85, 0.5, and 0.15 were found for Ce, Nd and Eu while a value of 0.65 was obtained for Pr from a plot of measured distribution coefficient versus ionic radius. These results show the feasibility of removing rare earth impurities to the ppb level from LaCl3. After purification, LaC13 is converted to LaF3