ISSN 1070-4272, 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.
PHYSICOCHEMICAL STUDIES
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 defined by the behavior of TeCl , which is
4
liberated on the decomposition of samples.
DOI: 10.1134/S1070427210080355
The present work is a continuation of the studies
1–3] of mechanisms of the thermal dissociation of hexa-
Crystals of Rb TeC1 were identified by crystal opti-
2 6
[
cal, X-ray, and chemical analyses. The chemical analysis
was fulfilled 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%.
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 defined by the behavior of ТеСl4
evolved on the decomposition of Rb ТеСI crystals.
2
6
Thermal stability of rubidium hexachlorotellurite in
argon atmosphere was studied by thermogravimetric
analysis. The complex thermal analysis was carried out
on a “Netzsch” STA429 CD installation using a DSC+TG
holder of samples and PtPtRh S-type thermocouples (10).
The analysis was carried out in corundum crucibles in
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.
3
–1
an argon flow (30 + 10 = 40 cm min ), the samples were
heated from room temperature up to 650°С with a rate of
–
1
1
0 deg min and cooled from 650 up to 60–100°С with
the same rate.
EXPERIMENTAL
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 Rb2ТеС16 crystals.
2
Crystals of Rb ТеС1 were precipitated by the addi-
2
6
After pressing the tablets were weighed with an accuracy
tion of a precipitating agent obtained by the dissolution
of ±5 μg and placed in corundum crucibles.
of ТеО (analytical grade) in strong hydrochloric acid
2
(
chemically-pure grade) [4] to a solution of rubidium
Products of Rb ТеС1 decomposition in an atmosphere
2
6
chloride. The resulting Rb TeC1 crystals were filtered,
with air access were analyzed by the X-ray fluorescence
and chemical methods. For this purpose weighed samples
of Rb ТеС1 in porcelain crucibles were placed in a muf-
2
6
washed out by ethanol, and dried up at 100°С. Then
Rb TeC1 crystals were recrystallized in 6 N НС1,
2
6
2
6
washed out, and dried up at 100°С.
fle furnace and held at a certain temperature within 1 h.
1
507