Investigations on the thermal decomposition of FeSO4·H2O-BaO2 mixtures were carried out under isothermal conditions by using simultaneously solid electrolyte cell (EMF-method). Evoked interactions producing oxygen in the temperature range 553-673 K were established by means of a solid electrolyte oxygen analyzer. Based on Mössbauer spectroscopy data and X-ray analysis it was proved that these reactions were associated with the release of oxygen from barium peroxide, oxidation of ferrosulphate-monohydrate to FeOHSO4, and formation of barium ferrites such as BaFe2O4 and BaFe12O19. 相似文献
The ability of some siliconates to hydrophobize and modify the surface of different kinds of asbestos was studied. A 6 wt% aqueous solution of potassium methylsiliconate was used in various quantities. After treatment, the asbestos samples were analysed by IR-spectroscopy, TG-DTA and electron microscopy. Structural changes were found on the asbestos surface, including the appearance of chemical bonds. The studies revealed that the sorption and lyophilic properties of asbestos are lowered, these being the basic preconditions for its injurious action on health. 相似文献
The development of equipment for thermal analysis has opened up new areas for applications in science, industrial practice
and environment studies. On the basis of the literature and information from equipment producers, the directions for the use
of thermal analysis in research and practice are classified. Special attention is paid to the possibilities of controlling
environmental pollution, and the stability and other properties of intermediate and final industrial products. It is stressed
that DSC and DTA systems can be successfully applied to determine enthalpy changes in raw materials and products as control
tests for their application. The advantages of coupled thermal systems for complex studies and the control of raw materials,
products and wastes are described.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
Summary The free energy of the acidic ammonium sulfate is a good precondition its use as an additive or reagent for decomposition of natural phosphates on the way to obtain NPS or NPKS complex fertilizers. During our previous studies it was confirmed that as a result of thermo-mechanical treatment new solid phases are formed as a result of the phosphates decomposition. The aim of this study is to find out appropriate conditions for thermal treatment of Tunisia phosphorite with ammonium sulfate where the content of P2O5 soluble forms has its maximum. The process was investigated under dynamic thermal conditions. Structure and phase transformations of the mixtures to intermediate and final solid products are confirmed by different techniques. X-ray powder diffraction, infrared spectroscopy and electron microscopy have been applied successfully and relationship found between phase structure and thermal treatment applied. As a result of the complex studies optimal temperatures are determined. The solid products under optimal conditions contain phosphorous in soluble forms available for plants in the soil. As a final it is concluded that the final products could be used as complex mineral fertilizers. 相似文献
Thermal decomposition of different inorganic sulphates are presented. A number of techniques, but mainly TG and DTA, are used to prove the mechanism and kinetics of CaSO4, BaSO4, FeSO4·xH2O, Al2(SO4)3·xH2O under various gas atmospheres. It is shown how the partial pressure of gas components and heating rate may effect the mechanism and kinetic parameters. There are also examples on the effects of some additives and initial treatment on the thermal processes. On the base of the results obtained some recommendations are given concerning the precautions to be taken into account in the thermal decomposition studies and the sulphur recovering. 相似文献
Coupled
TG-FTIR technique was used for identification of gaseous compounds evolved
at thermal treatment of six coal samples from different deposits (Bulgaria,
Russia, Ukraine). The experiments were carried out under dynamic heating conditions
up to 900°C at heating rates of 5, 10 or 50 K min–1
in a stream of dry air. The emission of CO2, H2O,
CO, SO2, COS, methane, methanol, formic acid, formaldehyde,
acetaldehyde, chlorobenzene was clearly identified in FTIR spectra of the
samples studied. The formation of ethanol, ethane, ethylene and p-xylene, at least on the level of traces, was also
identified. At the heating rate of 5°C min–1
the temperature of maximum intensities of the characteristic peaks of COS
was 270°C, of formaldehyde, formic acid, ethane and methanol 330°C,
of SO2, CO, acetic acid, ethylene and p-xylene
400°C and of chlorobenzene 500°C. At 10°C min–1
and 50°C min–1 these temperatures were
shifted, respectively, by 70–300°C and 150–450°C towards
higher temperatures and the respective absorption bands in FTIR spectra were,
as a rule, more intensive. 相似文献
The thermal behavior of epoxy-smectite nanocomposites (hybrids) is examined by non-isothermal thermogravimetry (TG, DTG and
DTA) in air atmosphere. It has been shown that the thermal stability of hybrids is much greater than that of epoxy resin and
strongly depends on both the smectite loading and the type of the gallery cations of organically modified smectites. The kinetics
of degradation of nanocomposites is significantly influenced by the presence of smectites and proceeds in three stages. Stage
I is attributed to the effect of quaternized ammonium ion exchanged smectite, as stages II and III are associated with the
decomposition of the bulk epoxy resin. Because of the interfacial interactions and thesilicate-polymer multilayered nanoscale
organization, the nanocomposites act as excellent heat insulator and mass transport barrier, which shift the thermal decomposition
peaks towards much higher temperatures.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
The data on the thermal decomposition of FeSO4?H2O upon various regimes of heating and gaseous environment prove the formation of intermediate products of the types Fe2O(SO4)2 and FeOHSO4, their stability and amount being determined mainly by temperature and oxygen-reduction potential.
This communication aims at presenting results on the synthesis and characterization of Fe2O(SO4)2. The synthesis was carried out using a laboratory thermal equipment operating under isothermal conditions in the temperature range 713–813 K in a gaseous environment either poor in oxygen or containing 100% oxygen. The experimental conditions under which Fe2O(SO4)2 is stable are established. The effect of three basic parameters on the synthesis of Fe2O(SO4)2 is clarified: the oxygen partial pressure, the ratio PH2O/PO2 and the temperature and the mode of heating. Mössbauer spectroscopy and X-ray diffraction data for Fe2O(SO4)2 are presented.
The thermal decomposition of FeS2 and BaO2 mixtures (mol ratio from 2 to 8) was studied in oxygen containing gas medium using dynamic heating rate. The solid decomposition products have been investigated with X-ray power diffraction and Mössbauer spectrometer. The thermal process has two main stages. In the presence of BaO2 the mixtures have a lower initial temperature of iron sulfide burning. The same time by the increasing of BaO2 content in the mixtures the diffusion difficulties are withdrawn in higher temperature ranges. It is proved that as intermediates BaSO4, nonstoichiometric sulfide, barium ferrites and Fe2O3 are formed. The content of many solid phases in the final product is in relationship with the initial ratio of BaO2 and FeS2. 相似文献