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The above process, known as "dehydration" or "calcination" of gypsum, takes place at the temperature range between ∼80 °C and ∼250 °C, depending on the heating rate, …
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Thermogravimetric and differential thermal analysis curves reveal that dehydration occurs in two stages. The diffraction peaks of β-hemihydrate with the trigonal space group P3121 gradually become...
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In order to study the physical and mechanical properties of gypsum rock samples in three states (natural, high-temperature dehydration and hydration time), natural gypsum rock …
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An ore of calcium sulfate dihydrate should exhibit four distinct thermal reactions evident in the DTA and TGA evaluations; 1) the first is an endotherm ending ∼105 …
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Stucco is formed by partial dehydration of gypsum (calcium sulfate dihydrate), a naturally occurring mineral. ... of temperature, should provide a convenient method for ... Weight Loss …
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During a test, the furnace temperature is either kept constant or increased at a fixed rate (typically between 1 and 60 °C/min) to predefined maximum temperature (routinely 1000 °C or higher). …
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The performance of composite gypsum at elevated temperatures depends on the treatment temperature and reflects the combined effects of gypsum phase change and the filler effects of …
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The dehydration mechanism of natural single crystals of gypsum was investigated in the temperature range 300-430 K by in situ infrared (FTIR) spectroscopy. The thermal …
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Gypsum (calcium sulfate dihydrate) is one of the most used inorganic binding materials in the world. During calcination, calcium sulfate subhydrates are formed and, for …
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Adding Fe2O3 to gypsum contributed a lowering of decomposition temperature of gypsum resulting in formation of calcium ferrite in lower temperature. Decomposition of …
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Thermal properties and microstructure of gypsum board and its dehydration products: A theoretical and experimental investigation Q. L. Yu*,† and H. J. H. Brouwers Department of …
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Calcined gypsum (commonly known as a Plaster of Paris) in powder form consists mainly of calcium sulphate hemihydrate CaSO 4 ·1/2H 2 O, which is prepared by dehydration …
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The calcium sulphate dihydrate gypsum (CaSO 4 ·2H 2 O) is the most common sulphate evaporite mineral on our planet 1.Sulphate evaporites play an important role in …
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1. Ultrasonic results indicate gypsum hydration reaction consists of two stages: the dissolution of hemihydrate in the first stage and the nucleation and precipitation of dihydrate in the second …
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TL;DR: In this article, a kinetic study of the thermal decomposition of naturally-occurring gypsum and pure calcium sulphate dihydrate was conducted. And the results …
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The structure and composition of the gypsum at elevated temperatures were studied by means of scanning electron microscopy, X-ray diffraction (XRD) and …
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For calcium sulphate dihydrate (gypsum) two serial dehydration steps are very near in temperature decomposition and overlapping in the thermogravimetric events is observed. The …
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During calcination, calcium sulfate subhydrates are formed and, for technical reasons, are mixed with water to form dihydrate again. Therefore, the dehydration process of …
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Temperature measurements at pre-selected board locations indicated three distinct stages of gypsum dehydration; free moisture evaporation, transformation of calcium sulfate …
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The dehydration of gypsum (CaSO 4 • 2H 2 O) into calcium sulfate hemihydrate (CaSO 4 • 0.5H 2 O) and anhydrites (-CaSO 4 and-CaSO 4) was carried out by heating under a constant …
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transition from hemihydrate gypsum to crystalline gypsum (dihydrate gypsum). This brief presents examples of TG/DTA and DSC measurements of the thermal changes of gypsum.
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The crystal structure of the grown crystals was confirmed to be very similar to that of calcium sulfate dihydrate (CaSO4·2H2O, gypsum). The temperature at which dehydration and …
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Gypsum board reaction kinetics at elevated temperatures — In cases that the core of a gypsum board might contain magnesium and calcium carbonate, a reduction of gypsum mass is …
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The DTA curve of α-CaSO 4 · 1/2H 2 O, recorded with an N 2 atmosphere of ca. 760 torr in the DTA cell and a heating rate of 12 °C/min is shown in figure 6.Results of pressure dependence …
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When dehydration or decomposition causes a weight change and the DTG signal (TG differential signal) passes over the upper limit threshold, the temperature temporarily stops rising. At this …
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At higher temperatures the super-saturation is lower and the expected reaction speed is lower. However, as the ions can move faster at higher temperature, the speed of the …
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4-1 Temperature Change in Drying and Dehydration of Gypsum in a Fluidized Bed Fig. 2 illustrates a typical change of interior tempera-tures with time during the drying and …
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2.2. Dehydration of gypsum When heated, gypsum takes two steps of endothermic decomposition reactions [3–5]. When the first dehydration reaction occurs, CaSO 4 2H 2O is converted to …
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4-1 Temperature Change in Drying and Dehydration of Gypsum in a Fluidized Bed Fig. 2 illustrates a typical change of interior tempera-tures with time during the drying and …
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Drying and thermal dehydration of gypsum in the shape of thick circular plate and sphere ware investigated, especially by using a fluidized bed to reduce the film resistance for heat transfer. …
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