Prediction of Solubilities in the System Li⁺+Na⁺+K⁺+Cl^–+H₂O at 25 °C and Industrial Process of Refining Muriate of Potash

A modified Pitzer model at very high ionic strengths is developed in this work for quaternary systems consisting of three uniunivalent salts with a common ion and water. The proposed model is a combination of the extended Debye–Hückel model and the Pitzer model. This model satisfactorily describes the solubilities for the ternary LiCl+NaCl+H2O, LiCl+KCl+H2O, and NaCl+KCl+H2O systems at 25 °C, and it predicts reasonably acceptably the solubilities of the quaternary system LiCl+NaCl+KCl+H2O at 25 °C, when comparing with the experimental results of the literature and those obtained by the original Pitzer model with modified parameters high concentrations. In addition, the proposed model was applied to the process of refining muriate of potash on an industrial plant of a Chilean mining and chemical company.