tion engineering for the dehydration of a lump sample of gypsum was also developed by Sugiyama et al.1>3>10) andSugimoto et al.9). However, it has not yet been elucidated how …
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Figure 1: (left) Mass vs. temperature curves of gypsum during heating as measured by TGA. Two experiments were performed: open and closed. The one step process under open conditions is replaced by a two step dehydration …
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Water saturation has a weakening effect on the high-strength gypsum remolded sample. After high-temperature dehydration, the strength of the sample decreased by 73.09%. …
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This article investigates the thermal performance of gypsum boards in the dehydration temperature region, where pronounced chemical reactivity is anticipated. Gypsum board samples were gradually heated up to 3008C, …
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An experimental investigation was also developed by Ghazi Wakili and E. Hugi in 2009, dealing with thermal properties of the materials and comparing the fire behaviour of four types of …
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Considering the B1-B2 interface, time–temperature curves of specimen BR-SGP-S4 as an example (Fig. 10), at the beginning of the fire test, due to the large amount of heat …
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Gypsum plaster is an inorganic binder that is prepared in a two-step process. The first step is dehydration: heated to 100–200 °C, gypsum (CaSO 4 ·2H 2 O) releases water as …
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The dehydration products of gypsum under different temperature and water vapor pressure were investigated by thermodynamic theory. Additionally, the rehydration mechanism of soluble anhydrite...
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This study was the first CFD simulation effort to account for the two main macroscopic effects of gypsum dehydration, namely, the temperature-dependent GP …
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Figure 2 shows an overlay of gypsum DSC curves obtained with open crucibles in STA at atmospheric pres- sure and in DSC at 1, 16, 34, 50, and 67 bar. ... gypsum). The temperature at which ...
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According to the thermal curves, the gypsum dehydration comports two steps described by the following equations: CaSO 4 •2H 2 O( s )→CaSO 4 •1/2H 2 O( s )+3/2H 2 O( g ) (I)
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The curve of the hemihydrate solubilities is largely based on the data of Partridge and White (), Posnjak (), D'Ans et al. and Power et al. yielding a gypsum to hemihydrate transition temperature of 99 ± 4°C, which is in …
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Gypsum content determined from gravimetry of precipitated BaSO 4 as related to gypsum content from loss of its crystal water between three temperature intervals: 70 to 90°C, 70 to 105°C, and 70 ...
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Download scientific diagram | Pressure^temperature graph showing the gypsum-out curve from Zen (1965), the metastable bassanite-in curve of McConnell et al . (1987), 30 8 C km À 1 and 15 8 C km ...
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Nuclear magnetic resonance (NMR) is used to non-destructively measure the moisture and dehydration profiles in gypsum during one sided heating to temperatures of 400 …
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The dependence of the solubility of gypsum on temperature is nonlinear, reaching a maximum at 43°C. ... = Curves for gypsum and. ... that gypsum dehydration occurs widely.
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of temperature, should provide a convenient method for ... expected for complete dehydration of the gypsum to the anhydrite form. Examination of the weight loss derivative curve (dashed …
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Download scientific diagram | Thermal conductivity of gypsum, as reported by various researchers [1]. from publication: A combined experimental and numerical method for extracting …
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Calcined gypsum CaSO4.1/2H2O as a low-energy material can be produced with advantage from the waste flue gas desulfurization (FGD) gypsum CaSO4.2H 2 O by its dehydration at the …
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Example of TGA mass and mass loss rate curves (Type C gypsum board heated at 20 °C/min). Consider an experiment in which a (small) specimen of a material that is heated uniformly so …
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Gypsum presents a large latent heat due to its dehydration into hemihydrate and anhydrite. During a fire exposure, the gypsum panels are characterized by an isothermal stage on the unexposed side ...
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The dehydration started at the temperature under 50 °C and lasted up to 500 °C. The structure and composition of the gypsum at elevated temperatures were studied by …
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low-temperature dehydration of gypsum has been inves-tigated for many years. The rst analysis of the process is attributed to Flörke (1952), which indicated a two-step process CaSO 4 ·2H 2 …
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Therefore, the plot of temperature versus time corresponds to a real thermogravimetric curve, *m"f (¹ ), on which it is possible to identify each dehydration step. Characterization of the Dehydration Products Each gypsum …
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Methods. The dehydration process of FGD gypsum was performed with simultaneous TG/DSC analysis (NETZSCH STA 409 Luxx, Selb/Bavaria, Germany) at N 2 …
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In this work, we have reinvestigated the thermal degradation kinetics of synthetic gypsum (CaSO4·2H2O) using a novel approach based on peak deconvolution followed by the …
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Thermal behaviour and kinetics of dehydration of gypsum in air have been investigated using in situ real-time laboratory parallel-beam X-ray powder diffraction data …
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Gypsum quantitative determination in cements may be done from their thermogravimetric analysis (TG) data, which uses the mass of the water released from its …
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Temperature ( °C) Fig. 1. Example of TGA mass and mass loss rate curves (Type C gypsum board heated at 20 °C/min). ARRHENIUS-RATE THERMAL DECOMPOSITION KINETICS . …
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Download scientific diagram | European fire testing standard time/temperature curves (ISO 834 = curve #1). from publication: Enhanced Gypsum Panels for Fire Protection | The fireproofing materials ...
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