1068
YURTOV, MURASHOVA
determined for pure and commercial HDEHP.
2) The gelation region in the di(2-ethylhexyl) hy-
(
a)
(
drogen phosphate Cu(OH) (decane, hexane or tolu-
2
ene) water systems was determined at 20 C. A three-
dimensional network of organogels is built up by
copper(II) mono(2-ethylhexyl) phosphate crystals.
(3) Organogels based on copper(II) mono(2-etyl-
hexyl) phosphate or basic neodymium(III) di(2-ethyl-
hexyl) phosphate promote emulsification in extraction
systems.
(b)
(4) Different approaches to elimination of the
detrimental effect of structure formation in extrac-
tion systems containing copper(II) or lanthanide(III)
di(2-ethylhexyl) phosphates (e.g., meduse formation)
are analyzed.
Fig. 5. Photomicrographs of (a) emulsified HDEHP
ACKNOWLEDGMENTS
(
[
(
[
commercial) Cu(OH) decane water
system
with
2
HDEHP]/[Cu(OH) ] = 1.0 and (b) emulsified HDEHP
2
commercial) Nd(OH) decane water
system
with
This work was financially supported in part by
the Integration Special Federal Program (project
no. A0078/3,5).
3
HDEHP]/[Nd(OH) ] = 1.0. Scale: 16 mm = 100 m.
3
sharply narrows the gelation region in the extraction
systems containing copper(II) alkyl phosphates. As
a result, purification of the extractant to remove
REFERENCES
H MEHP decreases the probability of meduse forma-
2
1
2
3
4
. Rice, N.M., Hydrometallugy, 1981, vol. 7, pp. 177
99.
. Ritcey, G.M., Hydrometallugy, 1980, vol. 5, pp. 97
07.
. Rozen, A.M., Zakharkin, B.S., Nenarokomov, E.A.,
et al., At. Energ., 1992, vol. 72, vol. 5, pp. 436 440.
tion in the extraction. Under the industrial conditions,
the meduse formation is prevented by scrubbing a
commercial extractant with Na CO aqueous solution.
1
2
3
1
In going from commercial to pure HDEHP, the gela-
tion region of basic neodymium(III) di(2-ethylhexyl)
phosphates expands (Fig. 1). Therefore, unlike the
cases when, in extraction of metals with commercial
HDEHP, gel formation is promoted by organic im-
purities and, therefore, can be prevented by their re-
moval, in extraction of lanthanides(III) with HDEHP,
its purification to remove impurities does not prevent
the structure formation.
. Trifonov, Yu.I., Legin, E.K., and Suglobov, D.N.,
Proc. ISEC’90, Sekine, T., Ed., Tokyo: Elsevier,
1
992, pp. 279 284.
5
6
. Yurtov, E.V. and Murashova, N.M., Proc. Int. Symp.
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Our experiments showed that gel formation in the
organic phase is caused by basic alkyl phosphates
formed at HDEHP deficiency. At sufficiently high
acidity suppressing the metal hydrolysis, the meduse
formation can be prevented. At low metal concentra-
tion and large excess of the extractant, the probability
of meduse formation also decreases.
7
8
CONCLUSIONS
9. Peppard, D.F., Ferraro, J.R., and Mason, G.W.,
J. Inorg. Nucl. Chem., 1958, vol, 7, pp. 231 232.
(
1) Conditions of gelation in the basic neodymium
10. McDowell, W.J., Perdue, P.T., and Case, G.N.,
di(2-ethylhexyl) phosphate decane water system were
J. Inorg. Nucl. Chem., 1976, vol. 38, pp. 2127 2129.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 75 No. 7 2002