Solution-Mediated Transformation Kinetics of Calcium Sulfate Dihydrate to α-Calcium Sulfate Hemihydrate in CaCl2 Solutions at Elevated Temperature

被引：32

作者：

Fu, Hailu ^{[1
]}

Jiang, Guangming ^{[1
]}

Wang, Hao ^{[1
]}

Wu, Zhongbiao ^{[1
,2
]}

Guan, Baohong ^{[1
]}

机构：

[1] Zhejiang Univ, Dept Environm Engn, Hangzhou 310058, Zhejiang, Peoples R China

[2] Zhejiang Prov Engn Res Ctr Ind Boiler & Furnace G, Hangzhou 311202, Zhejiang, Peoples R China

来源：

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH | 2013年 / 52卷 / 48期

关键词：

FLUE-GAS DESULFURIZATION; POLYMORPHIC TRANSFORMATION; PHASE-TRANSFORMATION; GYPSUM CRYSTALLIZATION; HCL-CACL2-H2O SYSTEM; GROWTH KINETICS; CHEMICAL-MODEL; FGD GYPSUM; SOLUBILITY; HYDRATION;

D O I：

10.1021/ie402716d

中图分类号：

TQ [化学工业];

学科分类号：

0817 ;

摘要：

alpha-Calcium sulfate hemihydrate (alpha-HH), a kind of advanced cementitious material, can be prepared from calcium sulfate dihydrate (DH) in electrolyte solutions. The kinetics of the DH-alpha-HH transformation in CaCl2 solutions was investigated to better understand and, hence, control the transformation process. The results showed that the DH-alpha-HH transformation is a nucleation-growth limited process, following a dispersive kinetic model. The alpha-HH nucleation and growth were both promoted significantly with the increment of CaCl2 concentration and temperature. This is due to the enlarged activation entropy change and supersaturation, which were caused by the decreasing water activity and increasing solubility product ratio (K-sp,K-DH/K-sp,K-HH), respectively. The rate of DH-alpha-HH transformation in aqueous solutions can be effectively controlled by regulating water activity and temperature.

引用

页码：17134 / 17139

页数：6

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