Determination of the enthalpy and entropy of peritectic reaction in the CaO center dot SiO2(CS)-2CaO center dot SiO2(C2S)-2CaO center dot Al2O3 center dot SiO2(C(2)AS) system at the equilibrium temperature 1588 K

Inverse drop calorimetry performed in a SETARAM HTC 1800 K was used to meas ure the relative enthalpy value of the ternary peritectic melt (p.m.) in th e CS-C2S-C(2)AS system at the temperature 1754 K with regard to the referen ce state of a mechanical mixture of beta-C2S, CS, and C(2)AS crystals of co rresponding composition at 298 K. The same method was applied to measure th e relative enthalpy values of peritectic melt in the temperature interval 1 624 K-1775 K with regard to the reference state of its glass at 298 K. From these data the temperature-independent value of specific heat capacity of the peritectic melt was determined c(p)(p.m.) = (1.8213 +/- 0.1318) J g(-1) K-1 Using these quantities and the literature data of some enthalpic quantities for crystalline phases of compounds in the CS-C2S-C(2)AS system, the speci fic enthalpy of peritectic reaction (p.r.) in this system at equilibrium te mperature 1588 K was determined Delta(p.r.)h(1588K) = (231 +/- 33) J g(-1) For determination of this quantity the material balance of peritectic react ion and the material balance of dissociation of C3S2 to beta-C2S and CS wer e also used.