Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 8, pp. 1370−1374.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
D.E. Chirkst, O.L. Lobacheva, I.V. Berlinskii, M.A. Sulimova, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 8,
INORGANIC SYNTHESIS AND INDUSTRIAL
The ion ﬂ otation is a method for recovery of inactive,
as a rule, inorganic ions with the use of surfactants.
Surfactants are molecules containing a hydrophobic
and a hydrophilic parts, commonly represented by an
ionogenic group and an organic radical with a large
number of carbon atoms. In the course of ﬂ otation, the
surfactant interacts with the inorganic ion and can be
removed from the solution together with the foam.
The goal of this study was to examine the distribution
of rare-earth metal (REM) ions in the system constituted
by an aqueous phase and a foam phase, formed by
model solutions of Ce
nitrates and sodium
dodecyl sulfate, and to ﬁ nd the dissociation constant of
dodecylsulfuric acid, for which published data are rather
The dependence of the distribution coefﬁ cient of
rare-earth metals among the aqueous and organic phases
on the solution pH was studied to ﬁ nd conditions for
the most complete recovery of REM and determine
whether cerium(III) and yttrium(III) can be separated.
As model solutions were used 0.001 M aqueous
solutions of cerium(III) and yttrium(III) nitrates; as
a surfactant served sodium dodecyl sulfate (SDS) whose
concentration corresponded to the stoichiometry of the
i.e., it was 0.003 mol kg
, which constitutes 0.864 g kg
is the dodecyl sulfate ion).
The volume of the aqueous phase was varied from
100 to 200 ml, and the pH value, from 0 to 11 with a step
of 0.5 by addition of a nitric acid or sodium hydroxide
The ion ﬂ otation was performed during 10 min on
a 137 V-FL ﬂ otation machine of the mechanical type,
with a chamber volume of 1.0 dm
In solution, REM ions form strong complexes with
surfactants, and these complexes pass into the foam
phase because of the hydrophobicity of alkyl radicals.
The sampled foam was disintegrated by addition of
30 ml of a 1 mol kg
sulfuric acid solution. The resulting
solution (foam product) and the solution remaining in the
cuvette on performing the ﬂ otation (chamber residue)
were analyzed for the content of a rare-earth element by
the procedure described in : to an aliquot amount of
a solution under study (20 ml) were successively added
20 ml of a 5% solution of ascorbic acid, 5 drops of α-di-
nitrophenol indicator, a solution of sodium hydroxide or
nitric acid until the solution pH became about 4.5 (which
was judged from appearance of a yellow coloration), 5 ml
of an acetate buffer solution, 50 ml of distilled water, and
5 drops of Arsenazo-III indicator. The solution was titrated
with Trilon-B with a concentration of 0.05 mol kg
Recovery and Separation of Ce
Ions from Aqueous
Solutions by Ion Flotation
D. E. Chirkst, O. L. Lobacheva, I. V. Berlinskii, and M. A. Sulimova
St. Petersburg State Mining Institute, St. Petersburg, Russia
Received July 22, 2008
Abstract—Experimental dependences of the distribution coefficients of cerium(III) and yttrium(III) dodecyl
sulfates on the pH value of the equilibrium aqueous phase in the course of ion flotation are reported. Conditions
for separation of cerium(III) and yttrium(III) are discussed. A value of the dissociation constant found from
experimental results of potentiometric titration of dodecylsulfuric acid with sodium hydroxide is presented.