Effect of oxide ions on separation factors of actinides from lanthanides in reductive extraction

Moriyama, Hirotake*; Moritani, Kimikazu*; Toda, Taro*; Hayashi, Hirokazu 

The distribution coefficients of Am, Ce, and Eu between the salt and metal phases were measured at 1073 K in a reductive extraction system of equimolar NaCl-KCl melt and liquid Ga, which were expected to be higher from a thermodynamic point of view. By changing some solute concentrations, it was observed that the distribution coefficients were much dependent on the oxide ion concentration in the system, possibly due to the formation of such compounds as AmO and CeO. Also, in some runs, the mass balance of Am was affected possibly by the formation and precipitation of its oxychloride and/or oxide. By taking the observations into consideration, the separation factor between Am and Ce was obtained to be about 30 as a lower limit in the present system.