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

Enthalpy of incongruent decomposition of ЗСаО • Al₂0₃

K. Adamkovičová, L. Kosa, Š. Povraz, and I. Proks

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

Abstract: Using a precursor method tricalcium aluminate (C₃A) and peritectic melt formed at the incongruent decomposition of this compound at 1808 К were prepared. The peritectic melt consisted of 59.15 mass % CaO + 40.85 mass % Al₂0₃ . Calcium oxide used in the study was prepared by thermal decomposi­ tion of СаСОз. Temperature dependence of the specific relative enthalpy of the peritectic melt was determined combining the measurements of a"drop calorimetry" with the data obtained using a calorimeter for determination of heat of dissolution. Temperature dependences of the specific relative enthalpy of C₃A and CaO were determined on the basis of literature data and measurements of their heats of dissolution. Values of the specific relative enthalpies of C₃A, CaO, and peritectic melt at the temperature of 1808 К were used together with the material balance of the decomposition of C₃A for determination of the specific enthalpy of the incongruent decomposition of C₃A Δh_{in . die} (C₃A; 1808 K) = (306 ± 31) kJ kg^-1 Until now value of this quantity has not been calorimetrically determined.

Full paper in Portable Document Format: 391a3.pdf

Chemical Papers 39 (1) 3–13 (1985)