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have been described in previous quarterly re-
ports.21 Equilibrium data have been shown for
the case in which the pure metals have served as
the reducing agents and the solvent was NaZrF,.
By application of identical techniques, ad-
ditional data have been obtained on the UF,-Fe"
reaction, for reduction of tiF, by Inconel, and
for reactions of UF, with the pure metals in the
NaF-KF-LiF eutectic.
The results of some additional studies on the
system
Fe" + 2UF, = 2UF3 + FeF,
in KaF-ZrF, at 600 and 8OOOC are given in Table
5.3. In these experiments, 2 g of hydrogen-fired
iron wire was reacted with UF, in about 40 g of
NaF-ZrF,. The values for Kx reported are defined
as
'6F- 'FeF,
J L
Kx = I
C:F4
where the concen tions are given in mole frac-
tions with the NaF-ZrF, content considered as
equal to 2 moles. The values for the UF, concen-
,lJ. D. Redman and C. F. Weaver, ANP Qua7. Prog.
Rep. Sept. 10, 19 -1771, p 60.
TABLE 5.3. EQUILIBRIUM DATA FOR THE SYSTEM
Fe" + 2UF4 = 2UF3 + FeFZ IN MOLTEN NaF-ZrF,
AT 600 AND 8OO0C
UF, Added: 0.360 mole/kg of melt
C
Fett in Filtrote
*Blank of 100 ppm to be subtracted from determined
values in calculations.
PERIOD ENDING DECEMBER 'IO, 7954
trations have been calculated from the Fett
values found for the filtrates, since a reliable
method for determining UF, in this mixture is not
available.
It will be noted that the values given for Kx
at 600°C are larger than those at 8OO0C,. which
is in agreement with all previous measurements.
The values at the respective temperatures are
also in fair agreement with those given earlier.
The reaction between UF, and chromium in
lnconel with NaF-ZrF, as solvent has been in-
vestigated at 800°C. In these experiments, 2 g
of lnconel (hydrogen fired at 1200°C) WIJS con-
tacted with the melt for 5 hr prior to filtration.
The results are given in Table 5.4.
The values given in Table 5.4 for the equi-
librium constant are lower by about a iivefold
factor than those obtained when chromium metal
was used. It is possible that the activity of
chromium metal in lncanel is appreciably less
than its mole fraction. It appears more likely,
however, that these experiments represent "equi-
librium" with lnconel whose surface layer is
depleted of chromium metal. Additional data will
be obtained by using longer equilibration times
and varying surface-to-volume ratios.
A study of equilibria for reactions of Fe" and
Cr" with UF, in the NaF-KF-LiF eutectic has
been started. It has been observed that when
Fe" is equilibrated with the NaF-KF-LiF mixture
alone about 100 ppm of Fe (presumably Fe") is
found in the filtrate. This is very close to the
TABLE 5.4. DATA FBF! THE REACTION
Cr (INCONEL) + 2UF4 = 2UF3 + CrFz AT 800°C IN
MOLTEN NaF-ZrF,
UF, Added: 0.360 mole/kg of melt
**Activity of chromium in lnconel assumed to be equal
to mole fraction (0.2).
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