A method for comparing the thermochemical properties of high- boiling fractions and residues has been developed. The thermal effects vary in intensity and range, depending on the fractional and structure group compositions of the studied samples. Good agreement between DTA and TG data is observed. The thermal analysis of samples, obtained by liquid adsorption chromatography, reveals the specific differences of the individual structure group fractions in the processes of evaporation, thermal decomposition and coke formation. The observed effects are interpreted from the point of view of the different thermal stabilities and reactivities of the compounds contained in the Chromatographic fractions. The results show that the TG-DTA method allows the quick determination of some characteristics depending on the group compositions of the high-boiling fractions and residues from West Siberian crude oiL.
Theβ →γ transformation of Ca2SiO4 was investigated with regard to the disintegration of the sinter in alumina manufacturing. DTA was applied to study the effect of the reducing atmosphere upon the course of the polymorphic transitions of Ca2SiO4, and particularly the self-disintegration process. Pure synthetic dicalcium orthosilicate and blends of pure components from the system CaO-Al2O3-SiO2-Fe2O3 were compared with technological mixtures of limestone and fly ash. Data obtained from the DTA runs allowed the specification of technical parameter for both firing and cooling of the sinter.
This research was aimed
to investigate the role of clay on the combustion and kinetic behavior of
crude oils in limestone matrix. For this purpose, simultaneous TG (thermogravimetry)
and DTA (differential thermal analysis) experiments were performed at three
different heating rates as 10–15 and 20C min–1,
respectively. A uniform trend of decreasing activation energies was observed
with the addition of clay. It was concluded that clays surface area affects
the values of Arrhenius constant, while it is the catalytic properties of
clay, which lower the activation energies of all the reactions, involved in
the combustion process.
Authors:P. Pasierb, R. Gajerski, S. Komornicki, and M. Rękas
The binary system Li2CO3–BaCO3 was studied by means of differential thermal analysis (DTA), thermogravimetry (TG) and X-ray phase analysis. The composition
of carbonate and CO2 partial pressure influence on the thermal behavior of carbonate were examined. It was shown that lithium carbonate does not
form the substitutional solid solution with barium carbonate, however the possible formation of diluted interstitial solid
solutions is discussed. Above the melting temperature the mass loss is observed on TG curves. This loss is the result of both
decomposition of lithium carbonate and evaporation of lithium in Li2CO3–BaCO3 system. Increase of CO2 concentration in surrounding gas atmosphere leads to slower decomposition of lithium carbonate and to increase the melting
Authors:S. Marinković, A. Kostić-Pulek, S. Durić, V. Logar, and M. Logar
Selenite was boiled in KCl solutions of different concentrations at the respective boiling temperatures and atmospheric pressure. The products were subjected to X-ray diffraction analysis, qualitative infrared analysis, differential thermal analysis and microscopic examination. The product obtained in 1.0 M KCl solution was the -form of calcium sulphate hemihydrate (-CaSO4·0.5H2O). In more concentrated KCl solution (1.5, 2.0, 2.5, 3.0, 3.5 or 4.0 M), the -form of calcium sulphate hemihydrate (-CaSO4·0.5H2O) was formed, and a reaction took place between KCl and CaSO4, which gave a double salt: potassium pentacalcium sulphate monohydrate (K2SO4·5CaSO4·H2O).
Authors:Yu. Goltsov, L. Matkovskaya, V. Il'in, and V. Golovaty
The results of investigation of the influence of encapsulation on the mechanism of thermal decomposition of cyanide transition
metal complexes, based on data obtained by methods of differential thermal analysis (inert atmosphere) and thermodesorption
(mass-spectral monitoring of gaseous products) are represented. It was established, that encapsulation of cyanide iron(II)
and cobalt(III) complexes in faujasite type zeolite results in the hydrolytic mechanism of thermal destruction of complexes,
unlike to bulk analogues, which is determined by essential decreasing of the temperature of complex anions encapsulated destruction
beginning, up to temperatures while zeolite water molecules are saved; the gaseous products of thermal destruction composition
is determined by the peculiarities of localization of cations of different nature in inclusion compounds.