ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7

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Determination of the enthalpy of crystallization of eutectic melt in the system 2CaO.Al2O3.SiO2 - CaO.Al2O3. 2SiO2

L. Kosa, O. Žigo, K. Adamkovičová, and I. Proks

Institute of Inorganic Chemistry, Centre for Chemical Research, Slovak Academy of Sciences, CS-84236 Bratislava

 

Abstract: Using a precursor method the melt of eutectic composition in the system 2CaO • Al2O3 • SiO2 - CaO • Al2O3 • 2SiO2 (30.34 mass % CaO; 36.91 mass % Al2O3 ; 32.75 mass % Si02 ) and one of the products of its crystallization, viz. CaO • Al2O3 .2SiO2, were prepared. The temperature dependence of the spe­ cific relative enthalpy of the eutectic melt was determined using combination of the experimental data obtained in "drop" calorimeter and in the cal­orimeter for determination of heats of dissolution. The temperature depen­ dences of the specific relative enthalpy of the products of crystallization of the eutectic melt (these products being 2CaO •  Al2O3 • Si02 (gehlenite) and CaO •  Al2O3 • 2Si02 (anorthite)) were determined on the basis of literature data and the measured value of the specific heat of dissolution of CaO • Al2O3 • 2Si02 . On the basis of the values of the specific relative enthalpy of the eutectic melt and of the phases 2CaO • Al2O3  • Si02 and CaO • Al2O3 • 2Si02 related to the equilibrium temperature of crystallization of the eutectic melt 1658 К and from the material balance of the crystallization process the value of the specific enthalpy of crystallization of the eutectic melt was determined ∆hcryst(eut. melt; 1658K) = (- 441 ± 23) kJ kg-1 The error was determined on the level of significance equal to 95 %.

Full paper in Portable Document Format: 413a289.pdf

 

Chemical Papers 41 (3) 289–298 (1987)

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