ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 7, pp. 1140!1143. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + V.V. Vol
khin, I.S. Glushankova, S.A. Kolesova, E.A. Shul
ga, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81,
No. 7, pp. 1062!1065.
AND INDUSTRIAL INORGANIC CHEMISTRY
Sorption Recovery of Rubidium Ions from Highly Mineralized
Solutions to Obtain Rubidium Chloride of Reagent Grade
V. V. Vol
khin, I. S. Glushankova, S. A. Kolesova, andE. A. Shul
Perm State Technical University, Perm, Russia
Received June 7, 2007
Abstract-Recovery of Rb
ions from highly mineralized solutions with a granulated composite sorbent of
the composition K
in the multiple-cycle mode was studied.
Rubidium salts are obtained in industrial practice
as a by-product in processing of potassium and
magnesium salts by multiple fractionated crystalliza-
tion, and metallic rubidium, by reduction of rubidi-
um chloride with calcium at 7003800oC in a vacuum
. The high production cost of rubidium and its
salts hinders wide use of the metal in technology.
The techniques employed to obtain rare-earth
(REE) and scattered elements widely use extraction
and sorption methods [2, 3]. REEs are recovered
from solutions formed in processing of mineral raw
materials with selective inorganic ion-exchange ma-
terials or organic polymeric resins. To isolate REEs,
the sorbent is dissolved or subjected to thermal
degradation (ashing) .
It is advisable to use sorption methods to recover
rubidium from industrial brines (spent electrolytes,
aqueous solutions of chlorides of alkali and alkaline-
earth metals) formed in production of magnesium.
It is known that ferrocyanides [hexacyanofer-
rates(II)]of transition metals (copper, nickel, zinc)
can selectively absorb ions of rubidium, cesium, and
thallium(I) from solutions of various compositions,
with high separation coefficients achieved for ion
) [4, 7]. Granulated
sorbents are commonly used in sorption techniques.
To improve their mechanical properties, ferrocya-
nide sorbents are synthesized as composites, e.g.,
with silica gel .
Use of granulated composite ferrocyanide sorb-
ents makes it possible to organize the process by the
sorption3desorption3regeneration scheme, but the
lack of an efficient method for Rb
the sorbent hinders application of the sorption
technique to production of rubidium salts.
Ion-exchange and redox methods for desorption
of alkali metal ions from the ferrocyanide phase are
known. The ion-exchange techniques use concen-
trated solutions of ammonium chloride or nitrate,
with ammonium ions substituting alkali metal ions
in the solid phase. The desorption yields solutions
of alkali metal chlorides or nitrates with a large ex-
cess of ammonium ions, which hinders their further
The redox methods for desorption of alkali metal
ions are based on the reaction
stands for the ion of an alkali metal (Rb
), and M
, for Cu
The oxidation of a ferrocyanide is accompanied
by release of alkali metal ions from the sorbent
phase. In [4, 5, 7], 12 M H
and 6 M HNO
used as oxidizing agents for desorption of Rb
ions from the ferrocyanide sorbent. The dif-
ficulty of further processing of highly concentrated
acid solutions with a low content of the target com-
ponent hinders application of this technique.
The goal of the study was to develop a sorption
method for recovery of rubidium ions from highly
mineralized solutions to obtain a rubidium salt of