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  • Author or Editor: T. Zaremba x
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Abstract  

DTA, TG, XRD and IR methods were used to study the formation of solid solutions in the selected subsolidus range of the PbZrO3-K0.5Bi0.5TiO3 system by heating mixtures prepared using oxide substrates, i.e. PbO, Bi2O3, ZrO2, TiO2 and K2CO3. It was found that solid solutions are formed in the reaction of PbO and ZrO2 with intermediate compound, i.e. K0.5Bi0.5TiO3. PbZrO3 was not found to be formed as an intermediate phase.

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Abstract  

Synthesis of potassium bismuth titanate ferroelectric by heating of mixtures prepared using oxide precursors, i.e. Bi2O3, TiO2 and K2CO3 was investigated. DTA, TG, XRD and SEM methods were used to study the formation of intermediate compounds and the final product. Usage of associated homogenization and grinding of precursors mixture permits to decrease the temperature of formation of K0.5Bi0.5TiO3.

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Abstract  

Preliminary research has been carried out on the thermal modification of chrysotile asbestos. Destruction of the tubular structure of asbestos was achieved by calcination at 1000°C. In order to characterize the changes accompanying thermal modification both natural asbestos and calcined asbestos were subjected to thermogravimetric and differential thermal analysis, X-ray analysis and examination by scanning electron microscopy. The possibility of utilization of the calcined asbestos in the presence of a phosphate binder for the manufacture of refractory materials has been demonstrated.

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Abstract

Given the known carcinogenic effects, asbestos minerals are considered as general health hazard. Therefore, the elimination of asbestos materials from the environment is necessary. Asbestos minerals should be entirely transformed to a non-hazardous material. One of these methods is destructing the fibers structure of asbestos minerals by thermal treatment. Asbestos minerals are naturally occurring hydrous silicates, so that they decompose to release water by heating at high temperatures which may lead to changes in crystal structure and the formation of new phases without the dangerous properties. In this article, thermal behavior of asbestos minerals is investigated to observe the disappearance of this hazardous structure and to characterize products obtained by this way. Ten samples of asbestos minerals (six chrysotile samples from different locations, two samples of crocidolite, one amosite, and one tremolite) from different locations were tested. Mineralogical and morphological data (X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy) were obtained before and after differential thermal analysis.

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Abstract  

In this paper the examination results of chemical and phase composition as well as wastes graining from the semi-dry flue gas desulfurization (FGD) have been presented. The wastes contain mainly semi-hydrate calcium sulfite and calcium sulfate. The phase composition changes of wastes at the temperature of 350 and 600°C have been determined. On the basis of carried out examinations, possibilities of flue gas desulfurization wastes utilization in building materials production (sulfite and anhydrite cement) are proposed.

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Abstract  

This article reports the possibility of detoxification of chrysotile asbestos through a low temperature heating and grinding treatment. The effect of thermal treatment at different temperatures in the range from 500 to 725 °C for 3 h on raw natural asbestos was characterized by thermal analysis, X-ray diffraction, and scanning electron microscopy. It was found that an isothermal treatment at 650 °C caused the complete dehydroxylation of chrysotile Mg3Si2O5(OH)4. Transformation of the dehydroxylated phase to forsterite Mg2SiO4 was obtained by heat treatment in the range 650–725 °C. The study of microstructure changes of heated asbestos show the destruction of characteristic fibers of chrysotile and formation of strips of forsterite. It is easily milled to pulverulent-shape material by mechanical milling in vibratory mill.

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Abstract  

DTA, TG and XRD methods were used for the determination of by-product - obtained during flue gas desulfurization by means of introduction of dehydration - resisting sludge from water decarbonization system. Analysis results enabled the development and application of sludge utilization technology by means of semi-dry flue gas desulfurization in 'Siersza' power plant.

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Abstract  

Thermal decomposition of tetraethylammonium tetrachloro-, bromotrichloro-and tribromochloroferrates(III), of general formula [(C2H5)4N][FeBr4−nCln] (n=1, 3, 4), has been studied using the TG-MS, DTA and DTG techniques. The measurements were carried out in an argon atmosphere over the temperature range 293–1073 K. Solid products of the thermal decomposition were identified by Mössbauer spectroscopy.

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