THE RADIOCHEMISTRY OF PLUTONIUM - Sciencemadness.org

n2
w
:
G
.
4
3
I
c
-1
-2
\
\
1 I
z 4 6 8 10 12
~ HCI
Fig. 18. Extraction of some actinide
cations into 0.48 F H2MEHP in toluene
as a function of H~l concentration.313
Pu(VI) + Pu(IIf) = Pu(IV) + Pu(V)
Am(III), Pu, and U, ax-e extracted from 0.01
~ HN03 after stabilization of the Np in the
pentavalent state with NaN02. Np(V ) is then
oxidized to Np(VI) by an oxidizing agent and
extracted by HDEHP, and recovered from the
organic phase by reduction to Np(V) and
washing with O. 1 M HN03. Am(III) is back-
—
extracted from the HDEHP by 3 ~ HN03,
and the Pu recovered by reduction to Pu(HI)
and back extraction with 3 M HN03. Finally,
—
the U(VI) is returned to the aqueous phase by
back extraction with -1 ~ ammonium
carbonate.
Chudinov and Yakovlev
89 extracted U
and Pu away from Ifp(V ) with HDEHP as a
preliminary step in the calorimetric
determination of Np(lY ) with arsenazo (Il_f).
They state a Np sensitivity y of 0.04 ?/ml by
this method.
DBP was used by Markin and McKay 268
to prepare a pure Pu(V) solution in 0.2
—
M
HN03 . The method was ta extract Pu(IV )
from a mixture of Pu(IIf) and Pu(VI). The
reaction
is thus driven to completion leaving a pure Pu(V) solution in the aqueous phase.
Peppard et al. 311 used H MEHP in various diluents, and tri-n-octyl phosphine
2
oxide to effect a sequential separation of various tri-, tetra-, and hexavalent ions from
urine.
Peppard et al. 314 used HDEHP to separate Bk from other tripositive actinides
and from Pu. The Bk is oxidized to Bk(lY) in 10 M HN03 by 1 M KBr03 and extracted
— —
away from tripositive actinides. The Bk(lY) is then back extracted into 8 ~ HN03 by
‘eduction ‘ith ‘2°2 “
in the organic phase.
Amine Extractants
Pu is not reduced to Pu(III) under these conditions and remains
These compounds are long- chain alkyl or aryl primary, secondary, and
tertiary amines, and quaternary amine salts. Moore286 and Coleman
95
et al. have
given general reviews of the extraction of inorganic species by these compounds. The
amines react with acids to form an ion-association complex which is soluble in the
organic phase, illustrated by a tertiary amine
R3N(0)
+H++A-=R3NH+...A-
47
(0)
(1)