ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 8, pp. 1266!1270. C Pleiades Publishing, Inc., 2006.
Original Russian Text C A.K. Pyartman, V.V. Lishchuk, V.A. Keskinov, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 8,
AND ION-EXCHANGE PROCESSES
Extraction of Thorium(IV), Lantanum(III), and Yttrium(III)
Nitrates with a Composite Solid Extractant Based
on a Polymeric Support Impregnated with Trialkylamine
A. K. Pyartman, V. V. Lishchuk, and V. A. Keskinov
St. Petersburg State Technological Institute (Technical University), St. Petersburg, Russia
Received March 23, 2006
Abstract-Extraction of Th(IV), La(III), and Y(III) from aqueous solutions containing 034 M sodium nitrate
with a composite solid extractant based on a polymeric support impregnated with trialkylamine (Alamine-336)
was studied. The extraction isotherms were analyzed assuming that lanthanides and thorium are extracted
with the solid extractant in the form of complexes (R
] and (R
The extraction constants were calculated. The joint extraction of Th(IV) and La(III) [Y(III)] with the solid
extractant from aqueous salt solutions was studied.
Russian loparite, orthite, and monazite, along with
rare-earth metals, usually also contain thorium and
uranium as natural radioactive impurity metals. There-
fore, the separation of thorium and uranium from rare-
earth metals is a topical technological problem. This
problem is usually solved by solvent extraction .
Another approach to solution of this problem is the use
of composite solid extractants based on a porous sup-
port impregnated with a liquid extractant. This tech-
nique eliminates certain drawbacks characteristic of
common solvent extraction procedures.
The extraction of rare-earth metals(III) [REM(III)]
from aqueous solutions containing sodium nitrate (13
5 M ) with a composite solid extractant (SE) based on
a polymeric support impregnated with trialkylamine
(Alamine-336) was studied in . The extraction iso-
therms were processed assuming that the extractable
] is formed in the solid
extractant. No data have been reported on the joint
extraction of La
, and Y
from aqueous solu-
tions with the composite solid extractant. Since ex-
traction of these metals with solid extractants is im-
portant from both scientific and practical viewpoints,
we tried to fill this gap in this study.
We used a granulated composite solid extractant
(Purolite Company) based on super cross-linked, poly-
(styrene3divinylbenzene) matrix impregnated with
trialkylamine [TAA, (Alamine-336), general formula
N]. Its specific volume was 2.50 +
0.02 mol dm
. The Alamine-336 concentration in
the composite solid extractant was 0.97+0.01 mol dm
The REM(III) concentration in the solid extractant and
aqueous phase was determined by a technique similar
to that reported in . The metal nitrate concentra-
tion in SE (mol kg
) was recalculated to mol dm
taking into account the density of the composite solid
The relative errors were within + 0.5 % in prepar-
ing the solutions, and + (133) and + (135) rel. %, re-
spectively, in determining REM(III) [Th(IV)] concen-
tration in the liquid phase and SE. As a rule, each
final result was the average of the results of no less
than three experiments. The errors in parameter de-
termination are given as standard deviations.
Figure 1 shows the extraction isotherm of nitric
acid from aqueous solutions with SE at 298.15 K.
Fig. 1. Extraction isotherm of nitric acid with SE(TAA).
content in SE.