Application du modèle de Pitzer à l'étude de l'évaporation solaire isotherme des saumures naturelles

Abstract
The brine reserves of southern Tunisian chotts and sebkhats represent a source of mineral salts of a great interest, from which mineral salts can be recovered by isothermal solar evaporation. The evolution of density and ionic composition of the treated brine, during its isothermal evaporation, was studied. The experimental pathway of the evaporated brine was plotted on the oceanic quinary diagram Na⁺ , K⁺ , Mg²⁺, Cl^-, SO₄^2- // H₂O. In order to better understanding the observed chemical equilibria and, especially, to predict the precipitation sequences of mineral salts, during solar evaporation at 25°C, the theoretical pathway of the same studied brine was calculated using Pitzer's ion interaction model. The experimental, the theoretical and the calculated pathways are not the same.