ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
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: ∆hcryst (eut.melt; 1608 K) = (- 607 ± 28) kJ kg-1.
Full paper in Portable Document Format: 395a585.pdf
Chemical Papers 39 (5) 585–597 (1985)