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research and in industry for a preliminary estimation of the quality of calcined gypsum to be used for a specific purpose. The proposed calorimetric measurement and theoretical analysis enables one to obtain a partial phase composition of calcined

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transformations of the phase composition in the ternary Li 2 CO 3 –Fe 2 O 3 –ZnO system after thermal ( T ) and RT annealing of reaction mixtures at temperatures of 600 and 750 °C. When choosing the object of research, we took into account that alloyed lithium

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riverside sands. Considerable part of this type of ilmenite is produced from deposits in Australia [ 1 ]. Ilmenites differ not only in elemental composition, but also in phase composition. Ilmenite is one of the main raw materials for the titanium

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in air at a temperature of 700 °C without intermediate grinding and mixing. The phase composition of the examined samples was measured using an X-ray ARL X'tRA diffractometer with a Peltier Si(Li) semiconductor detector and Cu K α radiation

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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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Application of thermal analysis to determine a quantity portion of iron oxides in symmetric blast furnace sinters is presented. In the multicomponent sample, calcium ferrites and many silicate phases beside doped iron oxides phases were observed. The dependence of sinter phase composition from basicity and relation with physicochemical properties is defined.

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The reaction of sulphuric acid with titanium raw materials runs violently with simultaneous emission of gases. Such run of reaction creates danger of explosion. This process is very complicated from the reason of complexity of reactions and variety of compounds in reaction mixture. To determine safe conditions of reaction with high efficiency, it is necessary to investigate phase composition products of reaction. Products of reaction were investigated by using X-ray diffraction. However reaction products show high amorphy and this is the reason of difficulties to determine all phases. For this reason also was used additional method — ‘drop’ calorimeter. This method is used for determination of average specific heat of liquid or solid samples. In this case, this method was used for verification of phase composition of products of reaction. On the basis of investigation the phase composition of reaction product is following: titanyl sulfate, iron(III) sulfate, monohydrated iron(II) sulfate, magnesium sulfate and unreacted remainders of ilmenite and magnesium silicate.

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Possibilities have been studied of using a solvation model to predict the retention behavior of solutes in liquid chromatography mobile phases of water-acetonitrile and water-methanol with the organic solvent content varying from 1 to 100 vol%. Twenty-one test solutes, both aliphatic and aromatic compounds, have been selected on the basis of two-level factorial designs. Using the multiple linear regression analysis, regression coefficients, which are characteristics of the stationary and mobile-phase system, were calculated for different mobile phases in the solvation model. Regression coefficients have been used for the prediction of the retention behavior. Unbiased results have been obtained by using two sets, one training and the other the testing set. The predicted retention has been compared with the experimental data. The methanol-water system provided good results at low and medium methanol concentrations; the retention prediction was unsatisfactory for mobile phases containing more than 90% of methanol. The acetonitrile-water system yielded similar results, but the retention prediction ceased to be at acetonitrile concentrations greater than 80%. The retention has primarily been determined by cohesive and acid-base interactions. The dependences of the regression coefficients on the mobile-phase composition were similar for the acetonitrile-water and methanol-water systems.

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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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The literature data on the degree of crystallinity of non-deformed poly(ethylene terephthalate) measured at various temperatures have been subjected to comparative analysis. There is no correlation between the results obtained by the different methods. The reason for this is shown to be the imperfections in the methods of determining the degree of crystallinity, which do not provide the true composition of the crystalline phase. Consideration has been paid to the validity of the main principles involved in the thermal method of determining the degree of crystallinity, so as to eliminate the imperfections in the existing methods and to provide the correct value of the mass of the crystalline phase. The phase composition of PET has been analyzed by the thermal method at different temperatures and conditions of crystallization. A marked difference from the literature data is observed in the range of low temperatures.

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