-12-
Zr95_ p99,
In the subsequent ion-exchange separation based on Kraus
and Moore's method for divalent transition elements, almost all of the
radioactivity was eluted in the 0.5 M HCl fraction, which is known to
contain iron (Fig. 4).
Recount of two 0.5 M HCl fractions with 4.7
mg/cm? aluminum absorber reduced the count essentially to background, indicating that all of the activity was due to Fe.
of zr®5.Nb
Only a trace
95 was found in the ignited resin.
Secondary lon-exchange Separation of the pH 4. 1 Fraction
with Dowex 50
The pH 4. 1 fractions from the original ion-exchange separation
contained at least four radioisotopes.
These isotopes were almost
completely separated when the sample was passed through a second
Dowex 50 resin column and 5 per cent ammonium citrate solution at
pH's ranging from 2.8 to 6.1.
Figure 5 shows the elution pattern for
this separation and the radionuclides which were determined by gamma
spectrum analyses.
The major portion of the radioactivity was con-
tributed by Ce!44-pr!44 which was collected in the final 30 ml of the
pH 2.8 and the first 10 ml of the pH 3. 1 fractions.
Cs137 was collected
in the first part of the 2.8 and in the 3.3 fractions, but in neither of
these was it contaminated with other radioisotopes.
Mn*4 was present
in small amounts and was eluted with the pH 3. 1 ammonium citrate.
small amountof Co®° was found to contaminate the
lected in one of the 2.8 fractions.
A
Ce!44-pr144 ¢o}-
A portion of the radioactivity was