Some remarks on equilibrium state in dynamic condition

Abstract

For dehydration of CaC2O4.H2O and thermal dissociation of CaCO3 carried out in Mettler Toledo TGA/ SDTA-851e/STARe thermobalance similar experimental conditions was applied: 9-10 heating rates, q = 0.2, 0.5, 1, 2, 3, 6, 12, 24, 30, and 36 K min-1, for sample mass 10 mg, in nitrogen atmosphere (100 ml min-1) and in Al2O3 crucibles (70 ll). There were analyzed changes of typical TGA quantities, i.e., T, TG and DTG in the form of the relative rate of reaction/process intended to be analyzed on-line by formula (10). For comparative purposes, the relationship between experimental and equilibrium conversion degrees was used (for P = P). It was found that the solid phase decomposition proceeds in quasi-equilibrium state and enthalpy of reaction is easily "obscured" by activation energy. For small stoichiometric coefficients on gas phase side (here: m = 1) discussed decomposition processes have typical features of phenomena analyzable by known thermokinetic methods. © The Author(s) 2011.