. Dissolve ash in concentrated HCl, and filter to remove insolubles.
.
.
.
9.
step 6.
10.
Discard solid.
Precipitate, CaCO, by addition of concentrated Na.CO,; solution with mechanicalstirring.
Filter and check filtrate for completeness of precipitation by addition of Na.CO, solution.
Dry and weigh precipitate.
Redissolve precipitate in 50% HC! solution, filter and re-precipitate the carbonate as in
Filter off, dry, and weigh precipitate.
This procedure of re-crystallization should be re-
;y%
%
‘
j
:
t
peated until a constant weight of CaCO,is achieved, to insure maximum purity.
*
>
SIS oe 6 DD
b. Procedure for the determination of Sr~—90 in soil:
1. Sample in 2 pound batches is leached with twice the volume of 50% HCl with stirring
for five minutes.
. Filter off liquid, and save solid portion for further testing.
. Filtrate is evaporated to dryness.
. Ignite dry filtrate to remove organic material.
:
:
tteee fear
2. Add saturated solution of Na,CO, (with mechanical stirring) until precipitation is complete. After a short time has been allowed for the precipitate to settle, test supernatant liquid
for completeness of precipitation with a few drops of the carbonate.
3. Gently digest for fifteen minutes on hot plate.
4, Suction filter. Wash with distilled water.
5. Check filtrate for completeness of precipitation, with a few drops of saturated Na:CO;
solution. If clear, filtrate may be stored in can for other analyses.
6. Redissolve precipitate in 50% HCl solution keeping the volume to a minimum.
7. Filter to remove solid material.
8. Re-precipitate the SrCO;, following steps 3 through 6, except that the filtrate may be
discarded when precipitation is complete.
9. Dry and weigh precipitate.
10. Calculate yield.
11. Repeat steps 6 through 10 if yield indicates appreciable impurity.
12. Store sample in clean bottle until ready for milking as described on p. 29.
11. Store samples as the solid CaCO, ready for milking in the procedure described on p. 29.
c. Procedure for the determination of Sr—90 in bone and cheese:
OU WWM A
. Procedure for Sr-90 determination of shell samples:
. Dissolve sample in HCl.
Filter to remove insolubles,
Evaporate filtrate to dryness and ignite to remove organic debris.
Dissolve ash in concentrated HCl.
Filter off insolubles,
Precipitate CaCO; from the filtrate by addition of concentrated Na,CO, with mechanical
stirring.
28
8
RM
at
3. Precipitate Ca;(POQ,). by addition of a few ml. of H,PO, and raising pH with NH,OH, with
mechanical stirring.
4, Filter and check filtrate for completeness of precipitation by addition of NH,OH.
5. Dry and weigh precipitate.
6. Dissolve the weighed solid in hot concentrated HCl and repeat steps 3 through 5 until
a constant weight of precipitate is obtained.
7. Store sample as solid Ca, (PO,)2, ready for phosphate milking procedure described on p. 29.
be
ad
Discard solid.
ay
1. Ignite sample in oven at about 900°C until completely ashed.
2. Dissolve ash in concentrated HCI, and filter to remove insolubles.
‘a
708 AR@HIVES