Effects of Salts on the Hydration of <TEX>$alpha$</TEX>-Calcium Sulfate Hemihydrate

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J. Korean Ceram. Soc. > Volume 25(5); 1988 > Article

Journal of the Korean Ceramic Society 1988;25(5): 449.

$alpha$형 반수석고의 수화에 미치는 염류의 영향

최상흘, 이구종¹, 홍성윤, 이석곤

한양대학교 무기재료공학과
¹국립공업시험원 요업과

Effects of Salts on the Hydration of $alpha$-Calcium Sulfate Hemihydrate

ABSTRACT

The effects of salts which was used as a catalysis in formation of $alpha$-calciumusulfate hemihydrate from dicalcium sulfate hydrate were investigated on the hydration of $alpha$-calciumsulfate hemihydrate. The hydration of $alpha$-calciumsulfate hemihydrate was studied by the measurements of crystalline water, heat evolution. Also the hydrates were analyzed by XRD, DSC and SEM. The promotive effect each salts on the hydration was as follows: NaCl>NH4Cl>NaNO3>NH4NO3, and the hydration rate was accelerated with concentration of salts. The effect of Al2(SO4)3 and potassium sodium tartrate on the hydration was slmilar to water, whereas sodium succinate and gelatin retarded the hydration in comparision with water. These salts affected the hydration time but total heat evoution was similar.