K. Kinoshita et al., Separation of uranium and transuranic elements from rare earth elements bymeans of multistage extraction in LiCl-KCl/Bi system, J NUC SCI T, 36(2), 1999, pp. 189-197
A pyrometallurgical partitioning process is being developed for recovering
transuranic elements (TRUs) from high-level liquid waste. For estimating th
e separation efficiencies of TRUs from rare earth elements (REs), prelimina
ry measurements mere made of the distribution coefficients of TRUs in an Li
Cl-KCl/Bi system at 773 K. Actual separation of TRUs from REs was experimen
ted by multiple-batch extraction in LiCl-KCl/Bi system. The experimental re
sults agreed well with estimates obtained from measured separation factors
for single-step reductive extraction. A simulation study was performed in c
ounter-current extraction, for which the TRU recovery yields and separation
efficiencies were derived from the measured distribution coefficients. The
results indicated that counter-current extraction should permit recovering
more than 99% of every actinide contained in the high-level liquid waste,
while ensuring a mass ratio of TRUs to REs high enough for deriving metalli
c fuels for FBR.