THE RADIOCHEMISTRY OF PLUTONIUM - Sciencemadness.org
THE RADIOCHEMISTRY OF PLUTONIUM - Sciencemadness.org
THE RADIOCHEMISTRY OF PLUTONIUM - Sciencemadness.org
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Procedure 9b. Separation of Plutonium from Uranium Metal. J. Rydberg (Ref. 341)<br />
Outline of Method<br />
This procedure makes use of the co-precipitation properties of the different<br />
oxidation states of Pu on BiP04. The Pu is first oxidized to Pu(VI) which does not<br />
carry on BiP04, and then reduced to Pu(IV) which carries. An additional purification<br />
step is provided by extraction into TTA. Yield is greater than 60~0.<br />
Procedure<br />
1. The U sample is dissolved in hot cone, HN03 and kept at 90”C for 30<br />
rein, giving a soItition of U(VI) and Pu(IV).<br />
2. The solution is diluted to 5 ~ in HN03 and solid NaBi03 is added to<br />
oxidize Pu to the +6 valency state.<br />
3. The solution is made 0.1 ~ in HN03 (if it becomes turbid, HN03 is<br />
added until the solution is clear) and 0.1 ~ in phosphate. The BiP04<br />
precipitate is centrifuged off. This precipitate carries most of the<br />
fission products, and especially those with a chemistry similar to<br />
Pu(rv).<br />
4. The supernatant solution containing Pu(VI) is made 1 ~ in HN03 ,<br />
0.05 ~ in N2H4 and 0.005 ~ in FeH. In this solution Pu is rapidly<br />
reduced to Pu(III).<br />
5. The solution is diluted to 0.1 ~ in HN03 and made 0.1 ~ in phosphate.<br />
Bi+H M then added (1 drop O. 1 M Bi+H for each ml solution) to<br />
precipitate BiP04 , which carries all the Pu. The precipitate, which<br />
is usually contaminated with some U is centrifuged off and washed.<br />
6. The phosphates in the precipitate are converted into hydroxides by<br />
treating with warm -10 ~ KOH. After centrifuging the solution is<br />
drawn off, and the precipitate is washed and dissolved in hot cone.<br />
HN03.<br />
7. After some hours at room temperature, the solution is diluted to 1<br />
LMHY03, and extracted with an equal volume of 0.3 ~ thenoyltrifluoro-<br />
—<br />
acetone in benzene. This gives a pure Pu(IV) solution in the benzene<br />
phase, leaving the rest of the U and the fission products in the aqueous<br />
phase.<br />
8. If desired, the Pu(IV) can be back- etiracted in to the aqueous phase<br />
with 10 ~ HN03 or HC104 after a two-fold dilution of the <strong>org</strong>anic<br />
phase with benzene.<br />
130
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