Phase diagrams and thermochemical modeling of salt lake brine systems. III. Li2SO4+H2O, Na2SO4+H2O, K2SO4+H2O, MgSO4+H2O and CaSO4+H2O systems

This paper is part of a series of studies on the development of a multi-temperature thermodynamically consistent model for salt lake brine systems. Under the comprehensive thermodynamic framework proposed in our previous study, the thermodynamic and phase equilibria properties of the sulfate binary systems (i.e., Li2SO4 + H2O, Na2SO4 + H2O, K2SO4 + H2O, MgSO4 + H2O and CaSO4 + H2O) were simulated using the Pitzer-Simonson-Clegg (PSC) model. Various type of thermodynamic properties (i.e., water activity, osmotic coefficient, mean ionic activity coefficient, enthalpy of dilution and solution, relative apparent molar enthalpy, heat capacity of aqueous phase and solid phases) were collected and fitted to the model equations. The thermodynamic properties of these systems can be well reproduced or predicted using the obtained model parameters. Comparisons with the experimental or model values in literature indicate that the model parameters determined in this study can describe all of the thermodynamic and phase equilibria properties of these binary sulfate systems from infinite dilution to saturation and freezing point temperature to approx. 500 K.