Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 1, pp. 25−28.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © D.E. Chirkst, O.L. Lobacheva, N.V. Dzhevaga, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 1, pp. 28−31.
INORGANIC SYNTHESIS AND INDUSTRIAL
Ion Flotation of Lanthanum(III) and Holmium(III)
from Nitrate and Nitrate-Chloride Media
D. E. Chirkst, O. L. Lobacheva, and N. V. Dzhevaga
St. Petersburg State Mining Institute, St. Petersburg, Russia
Received February 25, 2011
Abstract—Ion ﬂ otation of lanthanum(III) and holmium(III) from nitrate and nitrate-chloride solutions with
sodium dodecyl sulfate was studied. The distribution coefﬁ cients and their dependence on pH were determined.
The development of modern technologies requires
an even growing number of new materials. Rare earth
metals (REMs) play an important role in metallurgy,
glass and ceramic manufacturing, and other industries.
Cerium lanthanides (lanthanum, cerium, and neodymium)
and some yttrium lanthanides (holmium, samarium, and
europium) are the most widely used individual REMs.
Misch metal containing 50% cerium, 30% lanthanum,
15% neodymium, and 5% praseodymium is extensively
used in steel treatment to remove free oxygen and sulfur
and the impurities of lead and antimony. Lanthanum oxide
is an important component of the optical glass used in the
manufacture of laboratory glassware with high thermal
stability and acid resistance. Holmium is a component of
some magnetic alloys; its compounds have found limited
application in the preparation of special glass, phosphors,
and some materials for microelectronics.
Individual REMs are most in demand in the global
market. The difﬁ culties consist in separating the certain
element from their sum and a small number of viable
REM deposits. In Russia, the main source of rare metal
raw is loparite ore of the Lovozerskoe deposit [1, 2].
Therefore, it is necessary to develop a technology for
obtaining a wide assortment of individual rare earth ele-
ments. Ion ﬂ otation, ensuring production of a concentrate
containing 60–70% of REM oxides, is the promising
The removal of lanthanides with naphthenic acid on
addition of chlorides to the concentration 0.1–0.15 M de-
creases the distribution coefﬁ cient due to the formation of
nonextractable chloro complexes . Because the chloro
complexes have the different strengths, this decrease is
different for each lanthanide, and, consequently, the fac-
tor of the Ce/Y separation increases from 1.5 to 14. In
ion ﬂ otation of REMs, the separation factors are low .
Therefore, it is of interest to study the effect of chloride
ions on the ion ﬂ otation process.
The ion ﬂotation was performed during 5 min on
a 137 V-FL laboratory ﬂotation machine with a cham-
ber volume of 1.0 dm
. As model solutions were used
0.001 M solutions of lanthanum and holmium nitrates
(both chemical purity grade). The volume of the solution
was 200 ml. As surfactant served dry sodium dodecyl
sulfate (SDS) whose concentration corresponded to the
stoichiometry of the reaction
i.e., it was 0.003 M (DS
is the dodecyl sulfate ion).
To initial solution, sodium chloride was also added in
amount corresponding to the concentrations 0.01 and
0.05 M. At 0.1 M NaCl the lanthanide ﬂ otation is inhib-
ited virtually completely. The resulting solution (foam
product) and the solution remaining in the chamber
(chamber residue) were separated and analyzed. The
foam was disintegrated by addition of 1 M sulfuric acid.
The concentration of REMs was determined photometri-
cally with Arsenazo-III indicator, the concentration of