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Cereal Research Communications
Authors: V. Kovacevic, D. Banaj, J. Kovacevic, A. Lalic, Z. Jurkovic, and M. Krizmanic

Antunovic M., Kovacevic V., Banaj D. (2002): Influences of liming on field crops yields on pseudoglay soils. In: Proceedings of the Union of Scientists-Rousse “Energy Efficiency and Agricultural Engineering, Vol

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Nazionale di Požarevac per avermi aiutato nel reperimento delle foto dei pezzi conservati nel loro museo. La mia gratitudine ADD va anche alla prof. Jelena Mrgić, della Facoltà di Filosofia a Belgrado, speciale per aver realizzato la mappa del limes della

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Cereal Research Communications
Authors: Svetislav Popovic, Marijana Tucak, and Zrinka Knezovic

Antunovic M. — Kovacevic V. — Banaj D.: 2002. Influences of liming on field crops yields on pseudoglay soils-In: Proceedings of the Union of Scientists-Rousse “Energy Efficiency and Agricultural Engineering, Vol

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different type of pozzolanic materials as additives to mortars and concretes, as well as to compare their properties. Most studies on the kinetics of metakaolin–lime interaction have been carried out under conditions, which are modeling the practical

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Journal of Thermal Analysis and Calorimetry
Authors: S. A. Abo-El-Enein, Z. M. Abou-Gamra, F. I. El-Hosiny, and S. M. A. El-Gamal

The hydration of two calcium hydroxide-silica fume mixtures was studied at 25°C. The mixtures were prepared at lime/silica molar ratios of 1.0 and 1.7. The free lime, free silica and chemically combined water contents were determined after various periods of hydration (0.5 h-90 days). Thus, the molar ratios CaO/SiO2 and H2O/SiO2 molar in the calcium silicate hydrates (C-S-H) formed could be derived. The hydrates formed were identified by using differential thermal analysis. The mechanism of the hydration-gardening thermal analysis. The mechanism of the hydration-hardening reaction between lime and silica fumes was suggested. The changes in the molar ratios CaO/SiO2 and H2O/SiO2 in the C-S-H formed with the time of hydration were found to follow the same trends as observed during the hydration course for the suggested mechanism.

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# This article was prepared within the framework of the DTP3-1-359-2.2 project “Living Danube Limes”. All dates are CE, unless stated otherwise. This work was supported by the National Cultural Fund of Hungary (NKA) under Grant Number 101108

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Abstract  

The hydration of two calcium hydroxide— silica fume mixtures was studied at 25°C, these are Mix I and Mix II with molar lime/silica ratios of 1 and 1.7, respectively. The free lime, free silica and chemically combined water contents were determined at various time of hydration from which the molar CaO/SiO2 ratios of the formed calcium silicate hydrate, C−S−H, were calculated. The results indicated that hydration takes place in six steps where C−S−H (I) is formed at early stages of hydration, for Mix I, While for Mix II formation of C−S−H (I) and C−S−H (II) were detected by X-ray diffraction analysis and differential thermal analysis.

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Abstract  

A high speed method of thermal analysis was developed to allow the carbonation profile of lime mortars to be followed within a convenient time-frame. The loss in mass on heating, up to 700C, of lime/sand mixtures of different proportions was related to the known quantity of lime in each mixture. It was shown that a heating rate of 50C min–1 produced data which had a very high correlation with known quantities of Ca(OH)2. Thismethod can be used to measure the extent of carbonation at varying depths through a limemortar. This can be repeated at intervals to give an insight into the shape and extent of the carbonation front as it develops over time.

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Abstract  

A thermogravimetric method has been developed and is suggested for both the qualitative and quantitative phase analyses of high-calcium lime and calcium speciation as well. Two complementary TG measurements are proved to be satisfactory for the determination of moisture, calcium oxide, calcium hydroxide and calcium carbonate contents as well as total mineral impurities in high-calcium limes: quicklime, hydrated lime and limestone.

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The effects of the presence of a Pt catalyst on the limestone/lime sulphation process were investigated by thermal analysis methods to provide a better understanding of the factors limiting gas desulphurization when Ca-based sorbents are used. It was found that for the Pt-catalysed sulphation of precalcined limestone the weight increase is above 100% higher under isothermal and dynamic conditions (up to 830°C). These results are direct evidence that Pt catalyses the CaO-SO2-O2 reaction. It can be presumed that the process proceeds through a gaseous intermediate, SO3, a highly reactive gas, which explains the increased rate of sulphation. SO3 then reacts with CaO to form CaSO4 directly, in contrast with the non-catalysed oxidation of SO2 to SO3, where CaSO3 formation is the most probable early stage of sulphation. The proposed mechanisms were supported by the phase identification of the products.

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