Solid–liquid equilibrium of K2SO4 in solvent mixtures at different temperatures

The objective of the present work is to represent the solid–liquid equilibrium of potassium sulfate in diverse water + organic solvent mixtures. This representation is carried out between 288.15 and 318.15 K in the following solvent mixtures: water + 1-propanol, water + methanol, water + ethanol and water + acetone. The experimental solubility data of the potassium sulfate in the diverse mixed solvents were obtained from literature, and the thermodynamic representation of the phase equilibrium is based on a simple methodology reported in the literature. Good agreements are observed between the results obtained in this work and the experimental solubility data of K2SO4 in the different solvent mixtures.Since these systems present a notable decrease in solubility owing to the effect of the cosolvent, making them potentially suitable for separating potassium sulfate by drowning-out the crystallization process, the amounts of salt precipitated, as a function of the weight percent of cosolvent, was calculated for the four systems analyzed. In addition, the optimum yield was estimated as function of the mass fraction of 1-propanol for the K2SO4 + water + 1-propanol system.