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

Determination of the enthalpy of crystallization of eutectic melt in the system 3CaO.Al₂O₃-12CaO.7Al₂O₃-2CaO.SiO₂

B. Švecová, K. Adamkovičová, L. Kosa, and I. Proks

Institute of Inorganic Chemistry, Centre for Chemical Research, Slovak Academy of Sciences, CS-842 36 Bratislava

Abstract: The sample having composition of the eutectic melt in the system ЗСаОАl₂О₃— 12СаО-7Аl₂О₃—2CaOSiO₂ (51.97 mass % CaO, 41.34 mass % Al₂O₃, 6.69 mass % SiO₂ ) and ϒ-Ca₂SiO₄ were prepared by reac­ tions of components in solid phase. Next two phases formed at crystallization of the eutectic melt at equilibrium temperature of 1335 °C (ЗСаО-Al₂O₃ and 12CaO-7Al₂O₃) were prepared by a precursor method. For determination of the temperature dependence of the specific relative enthalpy of the eutectic melt the combination of drop calorimetry with data obtained from the calorimeter for determination of heats of dissolution was used. Temperature dependences of specific relative enthalpies of C₃A, C₁₂A₇ , and ß-C₂S were determined on the basis of literature data and measured values of the specific heat of dissolution of C₃A, C₁₂A₇ , and ϒ-C₂S. Using the values of specific relative enthalpy of the eutectic melt, C₃A, C₁₂A₇ , and  ϒ-C₂S related to the equilibrium temperature 1608 К and material balance of crystallization of the eutectic melt the specific enthalpy of crystallization of the eutectic melt was determined:  ∆h_cryst (eut.melt; 1608 K) = (- 607 ± 28) kJ kg^-1.

Full paper in Portable Document Format: 395a585.pdf

Chemical Papers 39 (5) 585–597 (1985)