Zr?>-Nb??,
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?”
95
Only a trace
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_p, 144 which was collected in the final 30 ml of the
pH 2.8 and the first 10 ml of the pH 3.1 fractions.
C137 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 wag eluted with the pH 3.1 ammonium citrate.
small amount of Co®°° was found to contaminate the
lected in one of the 2.8 fractions.
A
Cel44-prl44 col-
A portion of the radioactivity was