Dehydration Pathways of Gypsum and the
2019年4月26日 In this work, the dehydration pathways of gypsum and the rehydration mechanism of soluble anhydrite were mainly investigated by thermodynamic modeling and MC simulations. The dehydration pathways of
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Dehydration Pathways of Gypsum and the Rehydration
In the high-temperature and low water vapor pressure region, gypsum dehydrates to form γ-CaSO4 in a single-step process (CaSO42H2O γ -CaSO4); with increasing water vapor
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(PDF) Dehydration Pathways of Gypsum and the
2019年4月30日 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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Gypsum hydration: a theoretical and experimental study
2024年5月25日 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
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The dehydration process of gypsum under high pressure
2017年8月29日 gypsum-anhydrite dehydration reaction sequences at simultaneous high-pressure and temperature conditions. Mirwald (2008) performed a study of CaSO 4 H 2O
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The dehydration process of gypsum under high pressure
2011年9月30日 At 2.5 GPa, gypsum starts to dehydrate around 428 K, by forming bassanite, CaSO 4 hemihydrate, which completely dehydrates to γ-anhydrite at 488 K.
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Dehydration behavior of FGD gypsum by simultaneous TG ...
2010年10月26日 The dehydration of gypsum proceeded through one step, i.e., CaSO42H2O → γ-CaSO4 (γ-anhydrite) or two steps, i.e., CaSO42H2O → CaSO40.5H2O (hemihydrate) → γ
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Dehydration Pathways of Gypsum and the Rehydration Mechanism
2019年4月26日 In the high-temperature and low water vapor pressure region, gypsum dehydrates to form γ-CaSO 4 in a single-step process (CaSO 4 2H 2 O → γ-CaSO 4); with
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Kinetics of Gypsum Dehydration - Springer
2017年8月25日 The kinetics of gypsum dehydration in non-isothermal conditions with constant heating rate as well in quasi-isotherm, quasi-isobar regime, was investigated. The latter ones
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Formation of alpha;-Hemihydrate Inside of a
2022年12月8日 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 to
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Chemical Analysis of Gypsum and Gypsum Products
2015年2月21日 4.2 Gypsum (C 22/C 22M)—Gypsum samples will be re-ceived in the form of rocks, powder or both. If necessary crush and reduce the entire dried sample in accordance with 4.1.3 and 4.1.5. 4.3 Gypsum Plaster, (C 28). 4.3.1 Gypsum Ready-Mixed Plaster or Gypsum WoodFi-bered Plaster—Screen the dried sample through a 150-µm (No.
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Thermal Dehydration Kinetics of Gypsum and Borogypsum ...
Abstract: Thermal dehydration of gypsum and borogypsum was investigated under nonisothermal conditions in air by using simultaneous thermogravimetric-differentialthermal analyzer. Nonisothermal experiments were carried out at various linear heating rates.
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DEHYDRATION OF GYPSUM - Transport Research
The final product of dehydration was always anhydrous. Discontinuities in the weight loss versus time curves for powdered gypsum at a point corresponding to the loss of about 75 percent of the original sample water is evidence that dehydration involves consecutive reactions and not simply the transformation of gypsum to the anhydrous salt.
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(PDF) Dissolution and conversions of gypsum and anhydrite
2000年4月1日 The plot of the solubility product values against pressure and temperature according to Eqs. 2 to 4, for both gypsum and anhydrite, is shown in Fig. 5.
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Gypsum Properties, Formation, Uses and Deposits
2023年9月9日 Complete Dehydration: If gypsum is heated to higher temperatures and for an extended period, it loses all its water content, transforming into anhydrous calcium sulfate (CaSO4), commonly known as “anhydrite.” ... While the chemical formula for gypsum is relatively simple (CaSO42H2O), natural gypsum deposits may contain impurities ...
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Dehydration Pathways of Gypsum and the Rehydration Mechanism
2019年4月26日 The dehydration products of gypsum under different temperature and water vapor pressure were investigated by thermodynamic theory. Additionally, the rehydration mechanism of soluble anhydrite was also studied by Monte Carlo (MC) simulations. The thermodynamic calculation results reveal that the dehydration mechanism of gypsum
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Structural evolution of gypsum (CaSO>4>2H>2>O) during
The site occupancy of Ow in β–hemihydrate continuously decreases from 0.8 and reaches approximately 0.5 at temperatures of 130–140 °C, where soluble anhydrite with a hexagonal space group P6222 begins to form. Therefore, β– hemihydrate dehydration can be translated by the chemical formula CaSO4xH2O (0.5 ≤ x ≤ 0.8).
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Gypsum hydration: a theoretical and experimental study
2024年5月25日 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 stage. 2. Gypsum hydration is strongly influenced by water amount. Spread flow test is suitable to determine the water demand for gypsum hydration.
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Gypsum dehydration process - Big Chemical Encyclopedia
Gypsum dehydration process Isa and Oruno describe a method that enables identification of intermediates (in the gypsum dehydration process) more easily. The method involves the use of simultaneous TG-DTG-DTA under various sealed atmospheres corresponding to three systems—open completely, sealed, and quasi-sealed. Endothermic DTA peaks appear ...
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Kinetics of Gypsum Dehydration - Springer
2017年8月25日 KINETICS OF GYPSUM DEHYDRATION D. Fatu Department of Physical Chemistry, Blv. Elisabeta 4-12 Bucharest, 70346 Romania (Received June 6, 2000; in revised form January 25, 2001) Abstract The kinetics of gypsum dehydration in non-isothermal conditions with constant heating rate as well in quasi-isotherm, quasi-isobar regime, was investigated.
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Synthesis, Dehydration, and Rehydration of Calcium Sulfate (Gypsum ...
2014年3月31日 Download Citation Synthesis, Dehydration, and Rehydration of Calcium Sulfate (Gypsum, Plaster of Paris) Engaging students who are not chemistry majors is a significant challenge. Plaster of ...
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Gypsum And Plaster Of Paris / Plaster Of Paris(chemical Test)
Its chemical formula is CaSO 4. 0.5H 2O. So basically, Plaster of Paris chemistry involves the dehydration or heating of gypsum (calcium sulfate dihydrate) to form calcium sulfate hemihydrate. When gypsum is heated to a certain temperature, it loses its water content and becomes a dry powder, known as Plaster of Paris.
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What happens when heating gypsum at 373K to firm 'X'
**Heating Gypsum to Form 'X' Compound** **a) Chemical Equations of the Reactions:** When gypsum (calcium sulfate dihydrate, CaSO42H2O) is heated at 373K (100°C), it undergoes a dehydration reaction to form a new compound, 'X'. The chemical equation for this reaction can be represented as: CaSO42H2O (gypsum) → CaSO4½H2O + 1½H2O
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Investigation of the impurity effect on the kinetics of thermal ...
4 天之前 Gypsum is a non-combustible material, encoded as A1 according to the EN 13501–1 standard (gypsum binder for direct use) [13].Fire resistance is an important advantage when using gypsum in building construction [8].For this reason, gypsum plasters are widely used to provide passive protection of building materials from fire [14], [15] and, due to the non-flammable
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The Dehydration Kinetics of Gypsum in a Fluidized Bed Reactor
2000年10月1日 THE DEHYDRATION KINETICS OF GYPSUM IN AFLUIDIZED BED REACTOR S. R. CAVE and R. G. HOLDICH (AFFILIATE)Department of Chemical Engineering, LoughboroughUniversity, UKM easurements have been made of the rate of dehydration of desulphurized gypsumwith particle diameters in the range of 35±67 m m in a ¯uidized bed
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(PDF) The thermal dehydration of natural gypsum and pure
thermochimica acta ELSEVIER Thermochimica Acta 282/283 (1996) 483-492 The thermal dehydration of natural gypsum and pure calcium sulphate dihydrate (gypsum)l a,*, C.A. Strydom D.L. Hudson-Lamb aDepurtment of Chemistry, University of Pretoria, a, J.H. Potgieter b Pretoriu, 0002, South Africa b Technical Services, PPC, PO Box 40073, Cleveland 2022, South Africa
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Write the chemical name and formula of gypsum. What happens when gypsum ...
2018年7月10日 Chemical name of the gypsum-Calcium sulphate dihydrate Chemical formula of gypsum- CaSO 4.2H 2 O When Gypsum is heated at 373 K it will plaster of paris and water. CaSO 4 .2H 2 O+373K → CaSO 4 .1/2H 2 O+1 1/2 H 2 O
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Write the name of the products formed by heating gypsum
2018年3月14日 The chemical formula of Gypsum: CaSO 4.2H 2 O. When gypsum is heated at 373k, we get plaster of Paris. Chemical equation: Δ CaSO 4.2H 2 O ----->CaSO 4.1/2H 2 O +3/2 H 2 O. So, Calcium Sulphate Hemi hydrated salt --- CaSO 4.1/2H 2 O is produced after heating gypsum.. Plaster of paris is used in case of fracture.
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What is the chemical formula of GYPSUM ? Write chemical equation
2021年6月25日 Write balanced equation for (i) The preparation of phosphine from `CaO` and white phosphorus. (ii) The preparation of ammonium sulphate from gypsum, a asked Jun 18, 2019 in Chemistry by RenuYadav ( 94.2k points)
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