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The conversion of gypsum to anhydrite upon burial and heating is accompanied by about a 39% volume decrease, a four-fold increase in thermal conductivity, and consumption of heat. Accurate "back-stripping" of an evaporite basin and tracking its thermal evolution requires a knowledge of the depth of the gypsum …
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The Simulation and Analysis of Dehydration Process of FGD Gypsum Grouted Wall: ZENG Ziyue 1,2, YANG Jiansen 1, WEI Yongqi 2: 1 School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, Ningxia, China 2 School of Material Science and Engineering, Tongji University, Shanghai 201804, China
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DOI: 10.1016/S0167-2738(01)00755-X Corpus ID: 97032139; Microstructural modifications resulting from the dehydration of gypsum @article{Sipple2001MicrostructuralMR, title={Microstructural modifications resulting from the dehydration of gypsum}, author={E. M. Sipple and Pierre Bracconi and Ph.
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Calcium sulfate occurs in nature mainly in form of three different minerals distinguished by their degree of hydration: gypsum (CaSO 4 ), bassanite (CaSO 4 ⋅0.5H 2 O) and anhydrite (CaSO 4 ...
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Dehydration: One of the most notable chemical properties of gypsum is its ability to undergo controlled dehydration when heated. When gypsum is subjected to heat, typically at temperatures ranging …
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In this work, the dehydration pathways of gypsum and the rehydration mechanism of soluble anhydrite were mainly investigated by thermodynamic modeling …
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Gypsum undergoes brittle-ductile transition at moderate pressure (around 10 to 20 MPa confining pressure [Brantut et al., 2011]) …
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Volume 97, Number 4. April 2012 . Previous Article; Next Article; Article Contents. Article Navigation. ... The spectral behavior of gypsum dehydration in the visible to near-infrared (350–2500 nm) wavelength range was investigated by partially dehydrating the four main habits of gypsum (alabaster, satin spar, selenite, and massive) to form ...
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Gypsum board is a building material known for its various qualities and functional characteristics, including its low density, fire resistance, thermal insulation, moisture regulation, and decorative appeal. However, it is important to consider the environmental aspects, as the production of one ton of gypsum board releases …
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Gypsum (CaSO 4 ·2H 2 O) dehydration kinetics were investigated through energy dispersive X-ray diffraction (EDXD), under reduced pressure (100 Pa), in the temperature range 313–353 K. The process follows the JMAK (Johnson-Mehl-Avrami Kinetic) model. The fitting procedure of the Arrhenius expression provides an activation …
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volume change in the dehydration reaction the slope of the P-T line for the coexistence of gypsum and the hemihydrate at 385.65 K and 1000 bars was calculated to be 85.5 bars K- 1, which is close to the experimentally measured value of 81.1 bars K-1. ... DEHYDRATION OF GYPSUM TO BASSANITE ...
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Section snippets Thermo-chemistry of used materials. 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 of calcium sulphate dihydrate CaSO 4 ·2H 2 O (natural gypsum rock or an industrial by-product, e.g. from …
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(a) Unit-cell volume of the hemihydrate phase during the dehydration study of pure gypsum within a sealed capillary with an excess of water. (b) View of the ab plane of the hemihydrate structure with 0.5 water …
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First study of gypsum single crystal dehydration using X-ray absorption tomography. Evidence and mechanism of a multi-scale crack pattern due to structure …
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The tested material was gypsum paste prepared from calcined gypsum and water. The calcined gypsum used was a common commercial binder (producer Saint-Gobain Construction Products CZ a.s, Czech Republic), complying with EN 13279-1 [], prepared from flue gas desulphurization gypsum.Mineral composition of the binder, …
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The effects of pressure on the dehydration of gypsum materials were investigated up to 633 K and 25 GPa by using Raman spectroscopy and synchrotron X-ray diffraction with an externally heated diamond anvil cell. At 2.5 GPa, gypsum starts to dehydrate around 428 K, by forming bassanite, CaSO4 hemihydrate, which completely …
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We analyse the dehydration of gypsum to form bassanite and H2O which, like most dehydration reactions, produces a solid volume reduction leading to the formation of pore space.
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We analyse the dehydration of gypsum to form bassanite and H2O which, like most dehydration reactions, produces a solid volume …
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In order to achieve the resourceful, large-scale and high-value utilization of bulk industrial solid wastes such as flue gas desulfurization gypsum (FGDG), fly ash (FA) and ground blast furnace slag (GGBS), and to reduce the dosage of cementitious materials, orthogonal experimental methods were used to prepare composite cementitious …
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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 was put into high-temperature condition of 220°C for dehydration treatment, and then the high-temperature dehydrated gypsum rock was treated with different …
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Established in 2010, GLOBAL GYPSUM BOARD CO LLC is the first to operate gypsum board and value added plaster plants in the Sultanate of Oman, with production capacities of 15 Million sqm for 12.5mm thicknesss plasterboards, 60,000 MT/year of value added plaster and 150,000 MT/year stucco production capacity.
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The dehydration products of gypsum under different temperature and water vapor pressure were investigated by thermodynamic theory. ... CaSO4•0.5H2O) to gypsum (CaSO4•2 H2O), accompanied with a ...
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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 technical reasons, are mixed with water …
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Dehydration of axially pre-stressed, heated discs of natural gypsum rock (Volterra alabaster) was monitored in a purpose-built loading cell while collecting 2D …
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The gypsum-hemihydrate transformation has been long studied as a laboratory analogue for seismogenic dehydration reactions during subduction 8,9 and as a model of metamorphic dehydration reactions ...
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ture at which the dehydration events occur increases (T dehydration = 425.5 K in an open system, T dehydration = 439 K in a sealed system, in the presence of excess water). Compared with the wealth of high-temperature studies available, there is a lack of experimental studies on the gypsum-anhydrite dehydration reaction sequences at
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The dehydration process of a synthetic gypsum indicates that it has an interstitial gypsum phase dehydrating in a similar way to the interstitial phase found in the Terra Alba gypsum.
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This work has investigated the possibility of two common minerals (silica flour and talc powder) in modifying composite gypsum's physical and mechanical …
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The number of nuclei per solution volume unit influences the microstructure growth rate and crystal size ... An illustrative diagram of the steps from dihydrate dehydration up to hemihydrate hydration is shown in Fig. 1. ... Representation of the gypsum dehydration process; dissolution crystallization and hardening of the …
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