ORNL-1771 - Oak Ridge National Laboratory

ANP QUARTERLY PROGRESS REPORT
cathode was found to be about 8 amp,/cm2 of
nominal gauze area.
In all runs under hydrogen, the effluent gas was
bubbled through KOH solution to remove HF. A
sample of the gas after removal of HF was analyzed
by mass spectrometry and found to contain 3.17%
CH, 1.25% H,O (from the KQH solution), 0.73%
N, and only about 0.02% CF,. Evidently the
predominant anode product is HF. The anodes
disappeared at a rate corresponding to Q life ex-
pectancy longer than 50 ump-hr. The cathode de-
posits were expected to contain zirconium metal,
and this was qualitatively confirmed by the high
zirconium analysis (53.9 wt 5% for the cathode that
gained 0.2 g of iron) in the scrapings sf mixed
metal and salt from the cathode, However, the
zirconium metal could not be distinguished by x-ray
diffraction.
76
The conclusion was reached that electrolysis
with removable cathodes wus a practical and effi-
cient means of purifying fluoride melts containing
structural metal impurities. Experiments to investi-
gate the removal of sulfates and oxides by elec-
trolysis and an attempt to electralytical Iy reduce
UF, to UF, are in progress.
A typical set of current-voltage curves is shown
in Fig, 5.9. These curves apply to the experiment
with ternovable cathodes wnd illustrate the churac-
teristic “knees” or breaks in the current-voltage
curves as the voltage is increased or decreased.
The “knees” are apparently due to a polarization
phenora-ienon and show considerable hysteresis.
A correlation between the current at which breaks
occur and the ornpere-hours passed is presented in
Fig, 5.10.