THE RADIOCHEMISTRY OF PLUTONIUM - Sciencemadness.org

Procedure 2. Separation and determination of Pu by TTA extraction. F. L. Moore
and J. E. Hudgens, Jr. (Ref. 287).
Outline of Method
The sample is pre-treated if necessary, with either HN03 or by precipita-
ting LaF3 and dissolving in Al(No3) 3-HN03. The pre -treatment destroys any polymer
which may be present and assures the proper valence state (IV) for the TTA extraction.
Pu(IV) is extracted from 2 ~ HN03 and stripped into 10 ~ HN’03 , evaporated onto a
plate, and counted. Yield is quantitative.
Reagents
Hydroxylamine hydrochloride, 1 ~, is prepared by dissolving 69.5 grams
of C.P. grade and diluting it to 1 liter.
Sodium nitrite, 1 Ll, is prepared by dissolving 69 grams of C. P. grade and
diluting it to 1 liter.
2-Thenoyltrifluoroacetone -xylene O. 5~, is prepared by dissolving 111 grams of
the ketone and diluting it to 1 liter with C. P. xylene. (2 -Thenoyltrifluoro acetone
may be obtained from Graham, Crowley, and Associates, Inc., 5465 West Division
St., Chicago 51, D1. )
Pr etr eatrnent
Nitric acid method. A suitable a.liquot of the sample solution is pipetted
into a 100-ml volumetric flask containing 13 ml of concentrated nitric acid. The solu-
tion is heated carefully to a low boil on a hot plate and the temperature is held just
under boiling for 5 min. The solution is then made to a known volume with distilled
water. The nitric acid concentration of this solution should be approximately 2~.
~luoride method. A suitable aliquot ( 1 ml) of the sample solution is
pipetted into a 5-ml centrifuge cone. After addition of 0.4 ml of concentrated
hydrochloric acid and O. 1 ml of lanthanum carrier (5 mg per ml) the solution is
mixed well. Then 0.3 ml of hydroxylamine hydrochloride ( 5~) and 0.4 ml of hydro -
fluoric acid (27 ~) are added and the solution is stirred with a platinum stirrer.
After a 5-rein digestion at room temperature, the aoiution is centrifuged for 3 min.
Next, 0.1 ml of lanthanum carrier (5 mg per ml) is added and the supernatant is
stirred, care being taken not to disturb the precipitate. After another 5-rein digestion
at room temperature, the solution is centrifuged for 3 min and the supernatant is
removed with mild suction. The precipitate is washed twice with 0.5 -ml portions of
1~ nitric acid — 1 ~ hydrofluoric acid, centrifuging each time for 3 min. The
lanthanum fluoride precipitate containing tbe Pu is then dissolved in 0.3 ml of 2 ~
aluminum nitrate and 1 ml of 2 M nitric acid.
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This treatment not only aids in depolymerizing Pu(IV) but offers a method of
removing the Pu from interferences, as sulfuric acid, before performing the extrac-
tion. The liquid-liquid extraction technique described in this paper has been applied
successfully for several years to the purification and isolation of Pu isotopes.
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