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  • Author or Editor: K. Heide x
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Abstract  

Paleozoic black shales of the Saxothuringikum (Germany) with an average Corg. -content of 0.01 to 20 mass% were investigated with regard to the nature of organic matter. A special pyrolysis technique (DEGAS) was used for a temperature resolved analysis of different hydrocarbons (HC) and the simultaneous detection of inorganic volatiles during heating under vacuum up to 1450C. The presented data indicate three different forms of organic matter occurring in the investigated black shales (bitumen, kerogen and pyrobitumen). Finally the influence of an igneous dyke intrusion on the alteration of the organic matter was examined.

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Abstract  

Correlation of structure parameters of glasses and related crystals formed in homogeneous or heterogeneous nucleation processes by thermal treatment is discussed on the basis of DTA, TG and EGA measurements in relation to the textural patterns of the materials. For cordierite glass, crystallization of metastable disordered cordierite polymorphs is related to an exothermic heat evolution and simultaneous with a small weight loss (appr. 0.025%). By MS-EGA, evolution of water was determined during the transformation of the metastable melt to a metastable intermediate crystalline phase. Interpretation of the crystallization by comparing the available structure parameters of cordierite glasses and crystals alone is insufficient to explain the role of water in the kinetics of crystallization. Optical and electron microscopy of the primary crystallization phenomena show the metastable solid solution with low quartz-type structure. Interpretation of the crystallization behaviour in terms of conventional theory of nucleation and crystal growth is impossible.

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By means of the thermomicroscopy was demonstrated that the discrepancy between the experimental DSC- and TG-data on the decomposition of citric acid in the literature can be explained in terms of superimposing reactions (melting, decomposition, immiscibility, and crystallization), which have different reaction rates. The thermomicroscopy is especially useful explaining such kind of reactions. The thermal behaviour of citric acid can be used as a “model reaction” in technology.

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