1070-4272/03/7606-0859 $25.00 C 2003 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 76, No. 6, 2003, pp. 859!862. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 6, 2003,
Original Russian Text Copyright + 2003 by Tikhomirov, Orlov, Vidyaev.
AND INDUSTRIAL INORGANIC CHEMISTRY
Separation of Alkali Metals
I. A. Tikhomirov, A. A. Orlov, and D. G. Vidyaev
Tomsk Polytechnic University, Tomsk, Russia
Received April 26, 2002
Abstract-A new gallam-exchange technique for separation of alkali metals was developed. The alkali metal
separation factors were determined for the gallam-exchange systems LiGa3NaOH, LiGa3KOH, and KGa3
NaOH. The effect of temperature and concentration of the exchanging phases on the separation factors were
studied for the systems LiGa3NaOH and LiGa3KOH. Kinetic parameters of lithium, sodium, and potassium
element exchanges were determined. The properties of gallam-exchange and amalgam-exchange systems were
At present, special-purity materials find increasing
use in technology; the requirements to these materials
are growing steadily. Special purity is necessary in
certain cases for alkali metals.
In practice, alkali metals are separated and purified
by the amalgam-exchange technique [1, 2]. Its main
disadvantage consists in that it uses large amounts of
highly toxic mercury, which results in environment
contamination and makes more complicated the equip-
ment and safety measures in the separation industry.
In this context, studies aimed to develop high-per-
formance and environmentally safe methods for sep-
aration of alkali metals become topical.
An environmentally safe gallam-exchange tech-
nique for purification and separation of alkali metals,
in which an intermetallic compound of gallium and
alkali metal, gallam, is used instead of amalgam, was
developed in .
The present study is concerned with separation of
alkali metal pairs, Li and Na, Li and K, Na and K, in
exchange between a gallam and a hydroxide solution
of one of these metals.
Typical parameters of the efficiency of one or
another separation technique and, in particular, of
the gallam exchange, are the separation factor a and
kinetic parameters of the exchange and decomposition
of an intermetallic compound (gallam) brought in con-
tact with aqueous solutions of an alkali metal hydrox-
ide. The exchange rate depends on the rate of inter-
facial electrochemical reactions and on the rate of re-
agent supply from the bulk of the phases to the inter-
face. Therefore, the aim of the study was to determine
the separation factors for the indicated pairs of alkali
metals and the kinetic parameters of the exchange
process and thus to evaluate the efficiency of gallam-
exchange systems in separation and purification of
The gallam used in the experiments was obtained
by direct dissolution of metallic lithium of LE-1 brand
in chemically pure gallium (99.99% of the main sub-
stance) . Hydroxide solutions were prepared from
chemically pure NaOH and KOH and distilled water.
The experimental laboratory installation is shown
schematically in Fig. 1. The exchange was studied in
Fig. 1. Schematic of experimental laboratory installation.