ORNL-4191 - the Molten Salt Energy Technologies Web Site

as functions of temperature and metal-phase com-
position. Experimental procedures will essentially
duplicate those developed for the primary program.
'The results presented here on the reductive extrac-
tion of cerium from LiF-BeF, (66-34 mole %) into
the Bi-Pb eutectic mixture (56.3 at. % Si) are the
first of this experimental program.
As in previous related experiments, the distribu-
tion of cerium between the two liquid phases was
followed as a function of the lithium concentration
in the metal phase. However, only small fractions
of lithium added incrementally to the metal phase
remained in solution under equilibrium conditions.
Typical results obtained at 700°C (Fig. 12.6) show
that only 32% of the cerium could be removed from
the salt phase. In addition, analysis of the metal
phase could account for no more than 1 to 2% of
the cerium activity. Variations in temperature from
500 to 700T had little or no effect on either the
distribution of cerium between the two phases or on
the lithium concentration of the metal phase.
Attempts were made initially to measure the
electrical potential between a beryllium metal
electrode inserted in the salt phase and the molten
metal pool. Despite short contact periods of the
Beo rod with the salt mixture, substantial quanti-
ties of cerium activity accumulated on the beryl-
lium electrode. A large fraction of cerium activity
inissing from the two liquid phases collected on
the bery Ilium electrode during its accidental over-
night exposure to the salt mixture.
157
0 ANALYSES OF SAL1- PHASE
ORNL-WG G7-11826
0 ANAlYSES 01: MFTAL PHASE
WEiGHT OF SALT PHASE: 2.336 kg __
WEIGHT OF biETAL PHASF: 1.57.6 kg Bi
ti71 kg Pb
rre_L -4- .......______.._ I . . .I
Fig. 12.6. Reductive Extraction of Cerium from LiF-
BeFZ (66-34 mole %) into Molten Lead-Bismuth Eutectic
Mixture at 7OO0C.
Although the results of this experiment are some-
what inconclusive, they indicate that solid rare-
earth beryllides might be stable in this extraction
system. Because of this rather pronounced effect
of lead, the system Ph-Ki can probably be excluded
from use in the liquid-liquid extraction process for
rare-earth removal from the MSBR fuel solvent.