Gypsum Dehydration Volume

  • Thermo poro mechanics Modelling of Gypsum

    The phase transitions of these minerals are associated with considerable volume variations creation of porosity with local defects and water exchanges Such changes can jeopardise the integrity of structures when the conditions that trigger the phase transitions are encountered This paper uses advanced poromechanics to investigate the dehydration of gypsum when subjected to heating The

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  • Thermal properties and microstructure of gypsum board and

    4 is formed during gypsum dehydration which was also confirmed by Kuntze [4] and Paulik et al [5] The effect of experimental conditions such as temperature pressure and particle size of gypsum was investigated as well The dehydration reaction is endothermic that is an amount of energy is needed to break the crystal water [8 10] which also explains why gypsum has a good fire

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  • Thermal behaviour and kinetics of dehydration

    · 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 evaluated by the Rietveld method Thermal expansion has been analysed from 298 to 373 K The high temperature limits for the cell edges and for the cell volume calculated using the Einstein equation are × 10−6 × 10

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  • Study of Gypsum Dehydration Time in CaCl2

    The preparation of the alpha form of calcium sulphate hemihydrate is technically relatively complicated The idea is to allow molecules of water contained in gypsum to leave through dehydration in liquid form This can only be achieved under hydrothermal conditions namely in an autoclave or by increasing the boiling point of the solution in which the gypsum is located during dehydration

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  • Structural evolution during the dehydration of

    FIG 4 4 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 water molecules content at 230ºC The crystal structure data can be found in FIG 5 5Occupancy of the hemihydrate O 13 and O 14 oxygen atoms belonging to the water molecules

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  • 648 The dehydration of gypsum Part IV The

    The dehydration of gypsum Part IV The heat of immersion heat of hydration specific gravity sedimentation volume and bulk density of the dehydration products S J Gregg and E G J Willing Abstract The first page of this article is displayed as the abstract About

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  • Thermal dehydration kinetics of phosphogypsum

    6% gypsum depending on its purity to avoid flash immediate setting of cement also affect strength development and volume stability in the cement 21 24 Gypsum is the most common cement set ting retarder used in industry Gypsum is mixtures of mainly calcium sulphate dihydrate calcium sulphate hemydrate and calcium sulphate anhydrite

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  • Infrared Dehydration Method for Determining

    Percent gypsum was determined by extrapolation the dehydration curve vida infra to rate = 0 The use of computer graphics in developing the curves made this method very rapid about 15 min per determination The reproducibility of the IR method σ = was better than the barium sulfate method σ = over the 2 to 58% gypsum range studies The accuracies of the two methods were

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  • Structural evolution during the dehydration of

    FIG 4 4 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 water molecules content at 230ºC The crystal structure data can be found in FIG 5 5Occupancy of the hemihydrate O 13 and O 14 oxygen atoms belonging to the water molecules

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  • Thermal dehydration kinetics of phosphogypsum

    6% gypsum depending on its purity to avoid flash immediate setting of cement also affect strength development and volume stability in the cement 21 24 Gypsum is the most common cement set ting retarder used in industry Gypsum is mixtures of mainly calcium sulphate dihydrate calcium sulphate hemydrate and calcium sulphate anhydrite

    Get Price
  • Chemical Equation Dehydration Of Gypsum

    Thermal Behaviour And Kinetics Of Dehydration Of 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 evaluated by the rietveld expansion has been analysed from 298 to 373 high temperature limits for the cell edges and for the cell volume calculated using the

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  • DOISerbia Influence of the gypsum dehydration

    While dehydrating gypsum with additives at the temperatures of 800°C and 900°C the influence of alkali additives on both the crystalline structure of anhydrite and properties of anhydrite binder was investigated The industrial and wastes including other lowcost materials were used as additives Having heated them with gypsum the anhydrite with alkali activation properties was

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  • The thermal dehydration of synthetic gypsum

    · Volumes 269 270 20 December 1995 It can be expected that during the first part of the dehydration of gypsum at temperatures less than 95 using a heating rate of 5 min the influence of the dehydration of impurities will have a marked effect on the mass loss curve This will also make the kinetic investigation of a single reaction in this range impossible As soon as the

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  • Kinetics of Gypsum Dehydration in Journal of

    · Architecture and Architectonics Biology and Life Sciences Chemistry and Chemical Engineering Materials and Applied Sciences Medical and Health Sciences Social

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  • Gypsum Dehydration Page 1 of 1

    · Gypsum dehydration is necessary for it to become an effective set moderating agent Gypsum itself is insolouble and therefore cannot moderate the setting of the C3A in cement clinker For that to happen soluble sulphate must be present Dehydration of gypsum to hemihydrate renders it soluble Reply Page 1 of 1 1 reg reg Subscription Subscribe to International Cement Review 12

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  • Thermo poro mechanics Modelling of Gypsum

    The phase transitions of these minerals are associated with considerable volume variations creation of porosity with local defects and water exchanges Such changes can jeopardise the integrity of structures when the conditions that trigger the phase transitions are encountered This paper uses advanced poromechanics to investigate the dehydration of gypsum when subjected to heating The

    Get Price
  • Kinetics of Gypsum Dehydration in Journal of

    · Architecture and Architectonics Biology and Life Sciences Chemistry and Chemical Engineering Materials and Applied Sciences Medical and Health Sciences Social

    Get Price
  • 648 The dehydration of gypsum Part IV The

    The dehydration of gypsum Part IV The heat of immersion heat of hydration specific gravity sedimentation volume and bulk density of the dehydration products S J Gregg and E G J Willing Abstract The first page of this article is displayed as

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  • Dehydration induced damage and deformation in gypsum and

    Dehydration induced damage and deformation in gypsum and implications for subduction zone processes N Brantut 1 2 A Schubnel 1 E C David 3 E Héripré 4 Y Guéguen 1 and A Dimanov4 Received 28 July 2011 revised 25 December 2011 accepted 19 January 2012 published 10 March 2012 [1] Experimental heating tests were performed on Volterra gypsum to study the

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  • Kinetics of Gypsum Dehydration in Journal of

    · Architecture and Architectonics Biology and Life Sciences Chemistry and Chemical Engineering Materials and Applied Sciences Medical and Health Sciences Social

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  • The pressure dependence of the dehydration of gypsum to

    A new experimental determination of the stability relationships for the dehydration of gypsum to the hemihydrate mineral bassanite at elevated temperature and pressure is described The experimental method used depends on the observation of very small changes in pressure on the onset of reaction due to the potential volume change in the reaction The technique yields P T data of very high

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  • Gypsum Dehydration Of Cement

    Gypsum Dehydration Of Cement As a leading global manufacturer of crushing equipment milling equipment dressing equipment drying equipment and briquette equipment etc we offer advanced rational solutions for any size reduction requirements including quarry aggregate grinding production and complete plant plan

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  • Thermo poro mechanics Modelling of Gypsum

    The phase transitions of these minerals are associated with considerable volume variations creation of porosity with local defects and water exchanges Such changes can jeopardise the integrity of structures when the conditions that trigger the phase transitions are encountered This paper uses advanced poromechanics to investigate the dehydration of gypsum when subjected to heating The

    Get Price
  • Infrared Dehydration Method for Determining

    Percent gypsum was determined by extrapolation the dehydration curve vida infra to rate = 0 The use of computer graphics in developing the curves made this method very rapid about 15 min per determination The reproducibility of the IR method σ = was better than the barium sulfate method σ = over the 2 to 58% gypsum range studies The accuracies of the two methods were

    Get Price
  • 648 The dehydration of gypsum Part IV The

    The dehydration of gypsum Part IV The heat of immersion heat of hydration specific gravity sedimentation volume and bulk density of the dehydration products S J Gregg and E G J Willing Abstract The first page of this article is displayed as

    Get Price

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