Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 12, pp. 1862−1866.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © О.L. Lobacheva, D.E. Chirkst, N.V. Dzhevaga, V.Yu. Bazhin, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 12,
Ion Flotation of Cations of Cerium Group
О. L. Lobacheva, D. E. Chirkst, N. V. Dzhevaga, and V. Yu. Bazhin
National Mineral Resources University (University of Mines), St. Petersburg, Russia
Received December 10, 2013
Abstract—The results of experimental investigation of ion ﬂ otation in solution of cerium, samarium, and europium
nitrates as well as of sodium dodecyl sulfate, which was used as ﬂ otation reagent, were reported. The dependences
of the distribution coefﬁ cients of rare earth ions in the ion ﬂ otation on pH of an equilibrium aqueous phase were
obtained. Comparison of an extraction pH with a pH of hydrate formation allows making a conclusion on the
ﬂ otation form of cerium, samarium, and europium cations.
Methods of surface separations of substances now
are widely used for the extraction and separation of ions
of rare earth metals (REM) [1–3]. For the production of
a concentrate containing 60–80% of a mixed REM in the
form of oxides ore is processed mainly with the use of
ﬂ otation technology . Surfactants used in the ﬂ otation
are the molecules usually with ionic functional group
and organic radical with a large number of carbon atoms.
In the course of ﬂ otation the surfactant reacted with an
inorganic ion (in this case, metal cation) thereby formed
sublat can be removed from the solution.
In the study a distribution of rare earth ions of cerium
was examined in systems of
aqueous solution–organic phase (foam) formed by model
solutions of their nitrates and sodium dodecyl sulfate .
First ion ﬂ otation of cerium and samarium was performed
using dodecylbenzyl-diethylene triamine of tetraacetic
acid as a collector of sodium salt . Europium ions with
the content in the efﬂ uent from 110 to 210 mg L
extracted using cetylpyridinium bromide. Extraction was
about 96% .
For determining the conditions of the most complete
extraction of REM the dependence of the distribution
coefﬁ cient of REM between aqueous and organic phases
on the pH of solution was examined. Aqueous solutions
of nitrates of Ce
of concentration of
0.001 mol kg
were used as model and sodium dodecyl
sulfate, as a flotation reagent, whose concentration
corresponded to stoichiometry of the reaction М
, i.e., 0.003 mol kg
, that is 0.864 g kg
is dodecyl sulfate ion).
The pH was adjusted using nitric acid or sodium
hydroxide. The volume of ﬂ oated solution varied from
100 to 200 mL.
The process of foam ﬂ otation was carried out for
10 min in a high performance device: a mechanical
laboratory ﬂ otation machine V-FL 137 of a 1.0 dm
volume of the chamber, requiring small operating space.
REM ions in a solution form strong complexes with
a surfactant, which pass into the foam phase due to
hydrophobicity of alkyl radicals.
Destruction of probed foam was performed using
30 mL solution of sulfuric acid at a concentration of
1 mol L
. The resulting solution (foam ) and the solution
remained in the cell after ﬂ otation (chamber residue) were
analyzed for the content of the rare earth elements [6, 7];
20 mL of a solution of ascorbic acid at a 5% concentration,
5 drops of indicator α-dinitrophenol, sodium hydroxide
solution to pH of about 4.5, which was monitored by the
appearance of a yellow coloration, 5 mL of acetate buffer
solution, 50 mL of distilled water, and 5 drops of 0.1%
aqueous solution of the indicator arsenazo-III were added
to an aliquot of solution under study (20 mL). The solution
was titrated by Trilon B of a 0.05 mol kg
The distribution coefﬁ cients of cations Ce
in the ﬂ otation process and the pH of the equilibrium