Note 13
If a gravimetric technique is to be used for yield determination,
Bll of the calcium must be separated from strontium.
It is important
therefore, that a sufficient number of nitric acid separations be
performed to insure removal of calcium.
lead and barium also precipitate
under these conditions but are removed in the subsequent hydroxide and
chromate scavenging steps.
First Milk
1.
Add Ll ml of yttrium carrier solution.
2.
Heat in a water bath regulated at approximately 90 degrees C.
3. Adjust pH to & with NH),OH.
4,
Cool to room temperature and allow the precipitate to settle.
5.
Centrifuge for 5 minutes.
Decant, pouring the supernatant liquid
into another 40 mi centrifuge tube.
6.
Dissolve the precipitate with a minimum amount of concentrated EC1,
dilute to 5 mi and repeat steps 2 through 5.
‘solutions.
Combine the supernatant
Discard the precipitate.
{o
Add 1 ml barium carrier solution.
8.
Add 1 mi 6M acetic acid and 2 ml of 6M ammonium acetate solution.
The pH should be 5.5 (use narrow range pH paper).
9. Heat in a water bath regulated at approximately 90°C.
10. Add dropwise with stirring, 1 ml of 0.3M NapCr0; solution.
supernatant should have e chromate color.
more NapCrO), solution.
The
If it does not, then add
Ali the barium must be removed.
its Stir vigorously until precipitation is complete.
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