Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 8, pp. 1507−1509.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
S.I. Lyakh, V.M. Sizyakov, Yu.A. Zaitsev, E.V. Pigova, V.L. Ugolkov, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83,
No. 8, pp. 1400−1402.
OF SYSTEMS AND PROCESSES
Study of the Temperature Effect on the Process
of Rubidium Hexachlorotellurite Decomposition
S. I. Lyakh, V. M. Sizyakov, Yu. A. Zaitsev, E. V. Pigova, and V. L. Ugolkov
St. Petersburg State Mining Institute, St. Petersburg, Russia
Institute of Chemistry of Silicates, Russian Academy of Sciences, St. Petersburg, Russia
Received May 11, 2010
Abstract—Thermal dissociation of rubidium hexachlorotellurite in inert atmosphere (argon) and in atmosphere
with air access was studied. The DTG and DTA curves for the process of rubidium hexachlorotellurite thermal
dissociation in the argon atmosphere are given. Their character is deﬁ ned by the behavior of TeCl
, which is
liberated on the decomposition of samples.
The present work is a continuation of the studies
[1–3] of mechanisms of the thermal dissociation of hexa-
chlorotellurates of alkaline elements. The mechanism of
complicated transformations proceeding on the rubidium
hexachlorotellurite thermal dissociation is shown in the
works [1, 2]. It is mainly deﬁ ned by the behavior of ТеСl
evolved on the decomposition of Rb
The main aim of this work was to study the behavior of
rubidium hexachlorotellurite at its thermal decomposition
in various conditions (atmosphere and temperature) and
to analyze decomposition products for the determination
of their phase and chemical compositions. These data
can be useful for the development of pyrometallurgical
procedures of obtaining rubidium salts free from potas-
sium, and for the analytical chemistry of these metals.
Crystals of Rb
were precipitated by the addi-
tion of a precipitating agent obtained by the dissolution
(analytical grade) in strong hydrochloric acid
(chemically-pure grade)  to a solution of rubidium
chloride. The resulting Rb
crystals were ﬁ ltered,
washed out by ethanol, and dried up at 100°С. Then
crystals were recrystallized in 6 N НС1,
washed out, and dried up at 100°С.
Crystals of Rb
were identiﬁ ed by crystal opti-
cal, X-ray, and chemical analyses. The chemical analysis
was fulﬁ lled by the methods of iodometry and bichro-
matometry (tellurium), potentiometry (chloride ions), and
gravimetry (rubidium). Calculated: Те 24.94, Сl 41.63%.
Found: Те 24.84, Сl 41.86%.
Thermal stability of rubidium hexachlorotellurite in
argon atmosphere was studied by thermogravimetric
analysis. The complex thermal analysis was carried out
on a “Netzsch” STA 429 CD installation using a DSC+TG
holder of samples and PtPtRh S-type thermocouples (10).
The analysis was carried out in corundum crucibles in
an argon ﬂ ow (30 + 10 = 40 cm
), the samples were
heated from room temperature up to 650°С with a rate of
10 deg min
and cooled from 650 up to 60–100°С with
the same rate.
Tablets of 5.1 mm in diameter and 0.5 mm in height
weighing about 20 mg were molded under a pressure of
about 1 kg mm
from synthesized Rb
After pressing the tablets were weighed with an accuracy
of ±5 μg and placed in corundum crucibles.
Products of Rb
decomposition in an atmosphere
with air access were analyzed by the X-ray ﬂ uorescence
and chemical methods. For this purpose weighed samples
in porcelain crucibles were placed in a muf-
ﬂ e furnace and held at a certain temperature within 1 h.