Crystallization Kinetics of α-Hemihydrate Gypsum Prepared by Hydrothermal Method in Atmospheric Salt Solution Medium

α-Calcium sulfate hemihydrate (α-HH) is an important cementitious material, which can be prepared by hydrothermal method from calcium sulfate dihydrate (DH) in an electrolyte solution. Study of the conversion kinetics of DH to α-HH in NaCl solution is helpful for understanding the control process. I...

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Main Authors: Zhongqi Wei, Qin Zhang, Xianbo Li
Format: Article
Language:English
Published: MDPI AG 2021-07-01
Series:Crystals
Subjects:
Online Access:https://www.mdpi.com/2073-4352/11/8/843
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spelling doaj-975683f2f2a14595818a1199e3cbfb5a2021-08-26T13:39:08ZengMDPI AGCrystals2073-43522021-07-011184384310.3390/cryst11080843Crystallization Kinetics of α-Hemihydrate Gypsum Prepared by Hydrothermal Method in Atmospheric Salt Solution MediumZhongqi Wei0Qin Zhang1Xianbo Li2College of Mining, Guizhou University, Guiyang 550025, ChinaGuizhou Academy of Sciences, Guiyang 550001, ChinaCollege of Mining, Guizhou University, Guiyang 550025, Chinaα-Calcium sulfate hemihydrate (α-HH) is an important cementitious material, which can be prepared by hydrothermal method from calcium sulfate dihydrate (DH) in an electrolyte solution. Study of the conversion kinetics of DH to α-HH in NaCl solution is helpful for understanding the control process. In this paper, X-ray diffraction (XRD) patterns were applied to study the effect of temperature on the crystallization kinetics of α-HH to determine the kinetic parameters. The research results show that the sigmoidal shape of the α-HH crystallization curve follows the Avrami-Erofeev model, which describes the crystallization kinetics of α-HH formation. Applying Arrhenius law in experimental data and model calculations, an apparent activation energy of 124 kJ/mol for nucleation and an apparent activation energy of 810 kJ/mol for growth were obtained. By adjusting the temperature of the solution, the number of α-HH nucleation and growth steps increases, which can effectively increase the DH-α-HH conversion rate in the NaCI solution.https://www.mdpi.com/2073-4352/11/8/843α-calcium sulfate hemihydratehydrothermal methodcrystallization kinetics
collection DOAJ
language English
format Article
sources DOAJ
author Zhongqi Wei
Qin Zhang
Xianbo Li
spellingShingle Zhongqi Wei
Qin Zhang
Xianbo Li
Crystallization Kinetics of α-Hemihydrate Gypsum Prepared by Hydrothermal Method in Atmospheric Salt Solution Medium
Crystals
α-calcium sulfate hemihydrate
hydrothermal method
crystallization kinetics
author_facet Zhongqi Wei
Qin Zhang
Xianbo Li
author_sort Zhongqi Wei
title Crystallization Kinetics of α-Hemihydrate Gypsum Prepared by Hydrothermal Method in Atmospheric Salt Solution Medium
title_short Crystallization Kinetics of α-Hemihydrate Gypsum Prepared by Hydrothermal Method in Atmospheric Salt Solution Medium
title_full Crystallization Kinetics of α-Hemihydrate Gypsum Prepared by Hydrothermal Method in Atmospheric Salt Solution Medium
title_fullStr Crystallization Kinetics of α-Hemihydrate Gypsum Prepared by Hydrothermal Method in Atmospheric Salt Solution Medium
title_full_unstemmed Crystallization Kinetics of α-Hemihydrate Gypsum Prepared by Hydrothermal Method in Atmospheric Salt Solution Medium
title_sort crystallization kinetics of α-hemihydrate gypsum prepared by hydrothermal method in atmospheric salt solution medium
publisher MDPI AG
series Crystals
issn 2073-4352
publishDate 2021-07-01
description α-Calcium sulfate hemihydrate (α-HH) is an important cementitious material, which can be prepared by hydrothermal method from calcium sulfate dihydrate (DH) in an electrolyte solution. Study of the conversion kinetics of DH to α-HH in NaCl solution is helpful for understanding the control process. In this paper, X-ray diffraction (XRD) patterns were applied to study the effect of temperature on the crystallization kinetics of α-HH to determine the kinetic parameters. The research results show that the sigmoidal shape of the α-HH crystallization curve follows the Avrami-Erofeev model, which describes the crystallization kinetics of α-HH formation. Applying Arrhenius law in experimental data and model calculations, an apparent activation energy of 124 kJ/mol for nucleation and an apparent activation energy of 810 kJ/mol for growth were obtained. By adjusting the temperature of the solution, the number of α-HH nucleation and growth steps increases, which can effectively increase the DH-α-HH conversion rate in the NaCI solution.
topic α-calcium sulfate hemihydrate
hydrothermal method
crystallization kinetics
url https://www.mdpi.com/2073-4352/11/8/843
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AT qinzhang crystallizationkineticsofahemihydrategypsumpreparedbyhydrothermalmethodinatmosphericsaltsolutionmedium
AT xianboli crystallizationkineticsofahemihydrategypsumpreparedbyhydrothermalmethodinatmosphericsaltsolutionmedium
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