Indium hydroxides were prepared by the mixing of aqueous indium nitrate solution with sodium or ammonium hydroxide solutions
under various conditions. The thermal decomposition of the resulting materials was examined by thermogravimetry, differential
thermal analysis, X-ray diffraction study and infrared spectroscopy. It has been found that sodium hydroxide solution is more
suitable than the addition of ammonium hydroxide solution to prepare indium hydroxide in well crystallization; the thermal
decomposition of indium hydroxide, in which the composition is In(OH)3xH2O where x2, proceeds according to the following process: In(OH)3xH2Ocubic In(OH)3cubic In2O3
The thermal decomposition of unirradiated and -irradiated lead nitrate was studied by the gas evolution method. The decomposition proceeds through initial gas evolution, a short induction period, an acceleratory stage and a decay stage. The acceleratory and decay stages follow the Avrami-Erofeyev equation. Irradiation enhances the decomposition but does not affect the shape of the decomposition curve.
Authors:A. Baldea, D. Axente, M. Abrudean, V. Mercea, and C. Bratu
Thermal decomposition of uranium double fluoride in a screw reactor in the temperature range of 250–500 °C is presented. Using integral reactor relation, kinetic parameters are discussed in terms of the shrinking core grain model. Arrhenius global activation energy is also determined.
Authors:Y. A. Ribeiro, J. D. S. de Oliveira, M. I. G. Leles, S. A. Juiz, and M. Ionashiro
Thermogravimetry, derivative thermogravimetry (TG, DTG) and differential scanning calorimetry (DSC), were used to study the thermal behaviour of mefenamic acid, ibuprofen, acetaminophen, sodium diclofenac, phenylbutazone, dipyrone and salicylamide. The results led to thermal stability data and also to the interpretation concerning the thermal decomposition.
Authors:V. Logvinenko, O. Polunina, Yu. Mikhailov, K. Mikhailov, and B. Bokhonov
Thermal decomposition of silver acetate was studied (TG, DSC, mass-spectrometry, X-ray analysis, electron microscopy). Non-isothermal
thermogravimetric data (obtained at two different rates of linear heating) were used for kinetic studies. Kinetic parameters
were calculated only for the chosen decomposition step.
Authors:R. Frost, J. Bouzaid, A. Musumeci, J. Kloprogge, and W. Martens
stability and thermal decomposition pathways for synthetic iowaite have been
determined using thermogravimetry in conjunction with evolved gas mass spectrometry.
Chemical analysis showed the formula of the synthesised iowaite to be Mg6.27Fe1.73(Cl)1.07(OH)16(CO3)0.336.1H2O
and X-ray diffraction confirms the layered structure. Dehydration of the iowaite
occurred at 35 and 79C. Dehydroxylation occurred at 254 and 291C.
Both steps were associated with the loss of CO2. Hydrogen
chloride gas was evolved in two steps at 368 and 434C. The products of
the thermal decomposition were MgO and a spinel MgFe2O4.
Experimentally it was found to be difficult to eliminate CO2
from inclusion in the interlayer during the synthesis of the iowaite compound
and in this way the synthesised iowaite resembled the natural mineral.
Authors:J. M. Bouzaid, R. L. Frost, A. W. Musumeci, and W. N. Martens
stability and thermal decomposition pathways for synthetic woodallite have
been determined using thermogravimetry in conjunction with evolved gas mass
spectrometry. Chemical analysis showed the formula of the synthesised woodallite
to be Mg6.28Cr1.72Cl(OH)16(CO3)0.36⋅8.3H2O and X-ray diffraction confirms the layered
LDH structure. Dehydration of the woodallite occurred at 65C. Dehydroxylation
occurred at 302 and 338C. Both steps were associated with the loss of
carbonate. Hydrogen chloride gas was evolved over a wide temperature range
centred on 507C. The products of the thermal decomposition were MgO and
a spinel MgCr2O4. Experimentally
it was found to be difficult to eliminate CO2 from
inclusion in the interlayer during the synthesis of the woodallite compound
and in this way the synthesised woodallite resembled the natural mineral.
The conditions of thermal decomposition of Y, La, Ce(III), Pr, Nd, Sm, and Gd aconitates have been studied. On heating, the aconitate of Ce(III) loses crystallization water to yield anhydrous salt, which then is transformed in to oxide CeO2. The aconitates of Y, Pr, Nd, Sm, Eu and Gd decompose in three stages. First, aconitates undergo dehydration to form the anhydrous salts, which next decompose to Ln2O2CO3. In the last one the thermal decomposition of Ln2O2CO3 to Ln2O3 is accompanied by endothermic effect. Dehydration of aconitate of La undergoes in two stages. The anhydrous complex decomposes to La2O2CO3; this subsequently decomposes to La2O3.
The thermal decomposition of zirconium oxyhydroxides prepared by the mixture of aqueous zirconium oxychloride solutions and aqueous solutions of sodium hydroxide or ammonium hydroxide under various conditions has been examined by thermogravimetry, differential thermal analysis, X-ray diffraction study and infrared spectrophotometry. As a result, it is seen that the thermal decomposition of zirconium oxyhydroxide, in which the composition is ZrO2-x(OH)2x