Solubility prediction of HCl-MgCl2-H2O system at 50 ∘C using the ion-interaction model

The component solubility of HCl-MgCl2-H2O system at 50 ∘C was calculated by using Pitzer's ion-interaction model and its extended HW model. The values of the parameters of β(0), β(1), Cφ of HCl and MgCl2 were obtained from optimization of the literature data, and θMgH and ψMgHCl were derived by coupling activity coefficient with solubility data. The comparison between the results by using the parameters derived by us and the results by adopting the parameters coming from the literature indicated that the parameters obtained from the system of ionic strength of 0.1mol/kg≦I≦5mol/kg (MgCl2⋅6H2O was the solid phase) were not suitable to predict the solubility of the system of ionic strength of 14 mol/kg. This study could provide the theoretical basis for extracting LiCl and MgCl2⋅6H2O from salt lake brine by using HCl as the salting out reagent.