Influence of the Gypsum Dehydration Temperature and

2010-10-7  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

Get Price

(PDF) Influence of the gypsum dehydration temperature

Influence of the gypsum dehydration temperature and alkali additives on the properties of anhydrite cement.pdf Available via license: CC BY 4.0 Content may be subject

Get Price

DOISerbia - Influence of the gypsum dehydration ...

Influence of the gypsum dehydration temperature and alkali additives on the properties of anhydrite cement. Leskeviciene V. ... While dehydrating gypsum with

Get Price

Influence of the gypsum dehydration temperature and

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

Get Price

Dehydration Temperature of Gypsum - JST

(1) In an atomsphere, the primary dehydration temperature of natual dihydrated gypsum used as a test sample is 133°C while its secondary dehydration temperature

Get Price

(PDF) Influence of dehydration method on the

Influence of dehydration method on hemihydrate gypsum, hemihydrate phosphogypsum and processed hemihydrate phosphogypsum crystal morphology was researched. ...

Get Price

The thermal dehydration of synthetic gypsum - ScienceDirect

1995-12-20  The main dehydration of the calcium sulphate dehydrate part of synthetic gypsum occurs between 95 and 170°C (heating rate 5°C min −1) and seems to proceed via a process

Get Price

Influence of temperature, particle size and humidity on ...

The aim of the present work was to compare natural and chemical gypsums with respect to dehydration rate and to investigate the influence of air temperature

Get Price

(PDF) Dehydration Pathways of Gypsum and the

The thermodynamic calculation results reveal that the dehydration mechanism of gypsum significantly depended on ambient temperature and water vapor pressure.

Get Price

Temperature dependence of gypsum dissolution rates ...

2020-3-1  The temperature dependence, however, has not been widely reported, even though the temperature can vary widely among construction jobs [15,16]. The current paper

Get Price

Dehydration Temperature of Chemical Gypsum - J-STAGE

2011-3-7  (3) The first dehydratioh temperature slightly increasases when insoluble organic substances, metal oxides and hydroxides etc, cover the surface of or are occluded in the byproduced gypsum. (4) No such definite influence due to the impurities was found for the second dehydration.

Get Price

The thermal dehydration of synthetic gypsum - ScienceDirect

1995-12-20  Mass losses vary between 13.7 and 16.5% and heat of dehydration values between 377 and 420 J g −1 for the dehydration of ground and mixed inhomogeneous gypsum samples. As for the dehydration of CaSO 4 2H 2 O, the dehydration of synthetic gypsum proceeds via multi-step reactions. Using a heating rate of 5°C min −1, the very slow dehydration of CaSO 4 2H 2 O and impurities in the gypsum ...

Get Price

(PDF) Influence of dehydration method on the

Influence of dehydration method on hemihydrate gypsum, hemihydrate phosphogypsum and processed hemihydrate phosphogypsum crystal morphology was researched. ... Predictions of the temperature ...

Get Price

The influence of water-soluble impurities on thermal ...

2018-4-16  The paper presents the results of studies of the effect of water-soluble impurities on the thermal dehydration of phosphogypsum in a self-generated atmosphere, which are obtained by thermogravimetry and differential scanning calorimetry. For comparison, the results of the thermal dehydration of gypsum are given. The information about the change in activation energy depending

Get Price

Study of Gypsum Dehydration Time in CaCl2 Solution ...

The preparation of the alpha form of calcium sulphate hemihydrate is technically relatively complicated. The idea is to allow 1.5 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.

Get Price

Dehydration of gypsum under dry CO injection

Dehydration of gypsum under dry CO2 injection ... it has been possible to demonstrate the influence of supercritical CO2 on the ... lower than the transition temperature of gypsum-anhydrite in air

Get Price

View of Thermal dehydration kinetics of phosphogypsum ...

The difference in DTG and DTA profiles, among two PG, indicates the influence of sample origin, chemical composition and traces on dehydration behavior . The most obvious discrepancy is the temperature, at which gypsum begins to dehydrate.

Get Price

Refinement of Phosphogypsum by Selective Dehydration ...

The influence of dehydration temperature and time, dehydration rate, aging time, slurry density of hydration and sonication time on the yield and grade of gypsum were investigated.

Get Price

Effect of carboxymethylcellulose on gypsum re-hydration ...

2013-12-10  Starch, dextrin, and cellulose did not influence the gypsum rehydration process. The addition of only 0.025% carboxymethylcellulose (CMC) induced a significant increase in the initial and final setting time by 12% and 52%, respectively, without significantly affecting the mechanical strength of the hardened gypsum under this condition.

Get Price

Architecture:Gypsum and Gypsum Products.pdf-原创力文档

2017-12-16  DTA showing the influence of the temperature of dihydrate dehydration and the time of rehydration on the shape of the peak doublet (10 mg, 5°C/min, crucible with lid).[11] 466 Chapter 11 - Gypsum and Gypsum Products The influence

Get Price

(PDF) Low-temperature dehydration of gypsum single ...

The dehydration of gypsum was gypsum, the results of studying the effect of isochro- monitored by changes in the ESR spectrum and the nous annealing temperature on the intensity of the weight of a crystal upon isochronous and isothermal observed ESR lines were reported. In particular, it was annealings. shown in [4] that annealing affects the ...

Get Price

Influence of Gypsum on the Hydrothermal Reaction of

before pressure dehydration. The molded speci-mens were hydrothermally treated in an au-toclave at 180†Ž under saturated steam pressure for 1, 4, 10, 20, 40, 80, and 160 h. A specimen was prepared by stopping and allowing the au-toclave to cool down when the temperature reached 140†Ž.

Get Price

Gypsum: an investigation of microstructure and

2019-12-3  4. Dehydration of gypsum Gypsum contains about 21% of chemically combined water by weight, which will dissociate from the crystal lattice and vaporize when gypsum is exposed to fire or heated. A common understanding is that gypsum undergoes two endothermic decomposition reactions at two different temperature ranges. CaSO 4 2H 2

Get Price

Evaluation of Dehydration Temperature on Properties of ...

Gypsum plaster is a material used as internal covering of walls in Brazilian constructions. However, this material has short setting times and generates a great quantity of material loss. The low energy necessary to dehydrate the waste material for utilization becomes recycling methods viable, since the recycled products have the same properties of the commercial material.

Get Price

Experimental study of the dehydration reactions gypsum ...

2008-2-21  The system CaSO(4)-H(2)O, characterized by the three dehydration reactions gypsum-anhydrite, gypsum-bassanite, and bassanite-anhydrite, was reexamined by in situ differential pressure analysis in the temperature range of 60-350 degrees C up to 3.5 GPa pressure.

Get Price

Thermal conductivity of gypsum boards beyond

2014-2-6  Thermal conductivity of gypsum boards beyond dehydration temperature. K. Ghazi Wakili. Corresponding Author. Empa, Swiss Federal Laboratories for Materials Science and Technology, CH‐8600 Dübendorf, Switzerland.

Get Price

Influence of Heat Sink on the Mold Temperature of

The mold temperature was reduced by 16.8 °C when a gypsum mold was installed with a 40 mm thick heat sink in a parallel configuration. Moreover, the reduction of the mold temperature improved the deflection of the molded part from 0.78 mm to 0.54 mm.

Get Price

Scrutinizing Gypsum Board Thermal Performance at ...

2010-9-9  Physical properties of the gypsum board sample, that is density, specific heat, and thermal conductivity, were measured as a function of the dehydration temperature range. Results suggested that the thermal conductivity of the calcium anhydrate sulfate is higher than that of the hemi-hydrate, despite the fact that gypsum porosity increases ...

Get Price

View of Thermal dehydration kinetics of phosphogypsum ...

The difference in DTG and DTA profiles, among two PG, indicates the influence of sample origin, chemical composition and traces on dehydration behavior . The most obvious discrepancy is the temperature, at which gypsum begins to dehydrate.

Get Price

Architecture:Gypsum and Gypsum Products.pdf-原创力文档

2017-12-16  DTA showing the influence of the temperature of dihydrate dehydration and the time of rehydration on the shape of the peak doublet (10 mg, 5°C/min, crucible with lid).[11] 466 Chapter 11 - Gypsum and Gypsum Products The influence

Get Price