THE RADIOCHEMISTRY OF PLUTONIUM - Sciencemadness.org

‘“’m!r=% ‘“”EsFF?E
D
1.0
lo-.17F%%F1
I I I I 1 I
I I [ 1 I
,O-LLLLLLU
0 2 4 6 B 1“ 12 14
Aqueous HN03 Concentrotlon, ~
Fig. 20. The extraction of the hexavalent
actinide nitrates by 10 v/o TOA
in xylene.219
Io+
I I 1 I I I
I f [ a
AP I
D
,“* .
1
i ~ .x
APa X Ref.(13)
■ Pa (X)
r A
r~[
* I
/
vNPCZ)
● PU (m)
o Am (~
10-3
7 I -
0 I I
I I
O 2 4 6 8 10 12 14
Aqueous HN03 Concentration, ~
Fig. 21. The extraction of pentavalent
and trivalent actinide nitrates by 10 v/o
‘roA in xylene. 219
Keder et al. 218 determined that the extracted complex is M(N03 )62- for
quadrivalent actinides and M02 (N03 )3- for hexavalent actinides by spectrophotometric
measurements.
Homer and Coleman
187 420
and Weaver and Homer have determined the dis-
tribution coefficients of Pu(IV), Pu(III), and Pu(VI) for a number of amines from HN03
solutions, with results shown in Figs. 22, 23, and 24. Their Pu(IV) results for unsalted
tri-n-octylamine (TOA ) agree qualitatively with Keder et al. 219 and Baroncelli ~.~’
reach the maximum at a lower HN03 concentration. The other classes of amines reach
a maximum at around 9 M HN03. The effect of salting with NaN03 at a constant nitrate
—
concentration is to increase the distribution coefficient at lower acidities. Pu(III) and
Pu(VI) show very much lower distribution coefficients with all classes of amines (Fig.
23) although A1(N03)3 salting raises the D ~u(lll) to a relatively high value with tertiary
amines (Fig. 24).
Baroncelli et al. 36 measured the distribution of Pu(17J) between HN03 solutions and
“tricaprylamine” (TCA, sold as “Alamine 336, ” a mixture of n-octyl and n-decyl-amines),
with similar results. The amine was diluted in “Solvesso 100, ” an aromatic naphtha.
The extraction reached a maximum of approximately D = 140 at 4 ~ HN03, and was
strongly depressed by the presence of macro uranyl ion, which saturates the extractant.
In experiments varying the concentration of the TCA the formation of the hexanitrato
Pu(IV) complex is confirmed, but the slope of the log D Pu vs log TCA curve is 1.4 in the
presence of 1.5 ~ uranyl ion. The corresponding slope for U is 1, indicating the for-
mation of a uranyl trinitrate complex.
49
but