Solubility prediction in the ternary systems NaCl–RbCl–H2O, KCl–CsCl–H2O and KBr–CsBr–H2O at 25 ∘C using the ion-interaction model

The component solubilities in NaCl–RbCl–H2O, KCl–CsCl–H2O and KBr–CsBr–H2O systems at 25 ∘C were calculated by using the Pitzer ion interaction model and its extended HW models. Excellent agreement with experimental solubilities indicated that the models can be successfully used to calculate the component solubilities. This study affords the necessary parameters for solubility predictions of complicated systems containing rubidium and caesium and establishes a theoretical basis for the separation of these valuable metals from salt lake brine.