Effect of Salts on the Formation of <TEX>$alpha$</TEX>-Calcium Sulfate Hemihydrate from by-Product Gypsum of Phosphoric Acid Process under Water Vapor at Atmospheric Pressure

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J. Korean Ceram. Soc. > Volume 25(3); 1988 > Article

Journal of the Korean Ceramic Society 1988;25(3): 300.

상압 수증기중에서 인산 석고로부터 $alpha$형 반수석고의 생성에 미치는 염류의 영향

이구종, 최상흘¹

국립공업시험원 요업과
¹한양대학교 무기재료공학과

Effect of Salts on the Formation of $alpha$-Calcium Sulfate Hemihydrate from by-Product Gypsum of Phosphoric Acid Process under Water Vapor at Atmospheric Pressure

ABSTRACT

The catalytic effect of salts on formation of ${alpha}$-calcium sulfate hemihydrate under water vapor at atmospheric pressure was studied and the formation of q-calcium sulfate hemilydrate from by-product gypsum of phosphoric acid process was investigated. The order of catalytic effect of salts are as follow: Ammonium chloride>Sodium succinate>Calcium chloride>Sodium tartrate>Magnesium chloride The prismatic crystals was formed when ammonium chloride, calcium chloride and magnesium chloride was added, whereas the needle crystals was formed when sodium tartrate was added. Ammonium chlorideis most successful in catalytic effects in formation of ${alpha}$-calcium sulfate hermihydrate for the by-product gypsum of phosphoric acid process.