Modeling of the CoSO4-Li2SO4-H2O ternary phase diagram between 283.15 K and 348.15 K

A new set of ternary interaction parameters is proposed to describe the excess properties of aqueous solutions in the CoSO 4 -Li 2 SO 4 -H 2 O chemical system between 283.15 K and 348.15 K at P = 101.3 kPa, using the Pitzer formalism. The parameters were determined using a combination of (i) experimental solubility values between 283.15 K and 323.15 K coming from the literature and a new set of experimental osmotic coefficients at 298.15 K and 308.15 K, (ii) reliable solid-liquid equilibrium models based on Pitzer equations for the CoSO 4 -H 2 O and Li 2 SO 4 -H 2 O binary systems, from literature. The new interaction parameters defined in this study allow to reproduce correctly the change in the hydration state of salts with temperature (Li 2 SO 4 .H 2 O and CoSO 4 .nH 2 O with n = 1, 6, 7) as well as their solubility products but they also allow to accurately represent the experimental phase diagram of the CoSO 4 -Li 2 SO 4 -H 2 O system according to temperature. • Measurement of original osmotic coefficients in the CoSO₄–Li₂SO₄–H₂O system at 298.15 K and 308.15 K. • Determination of temperature-dependent Pitzer ternary interaction parameter for the CoSO₄–Li₂SO₄–H₂O system between 283.15 K and 348.15 K. • Accurate modeling of solid–liquid equilibria and osmotic coefficients using the obtained ternary interaction parameter.