Thermodynamic investigation of the CaOAl2O3CaSO4H2O system at 25°C and the influence of Na2O

The CaOAl2O3CaSO4H2O system at 25°C has been investigated by calculations on the equilibrium solubility surfaces of AH3, C3AH6, CH, C6AS3Hx, C4ASHx and gypsum. The results are in good agreement with the previous experimental data and make it possible to define the hydrates in equilibrium with aqueous solutions of varying compositions. Solid-aqueous equilibria are very sensitive to the presence in the systems of additional ions such as sodium.