The thermodynamic theoretical modeling of brines from the Chott Djerid, Southeastern Tunisia and Sebkha Bazer, Northeast Algeria between the initial solution and evaporation of 100% shows different geochemical evolutions and variable precipitated mineral species. This is due to different initial geochemical compositions, which are basically related to different geological and climatic contexts. A rigorous thermodynamic model has been presented for determining the crystallization sequence during the different stages of the evaporation process. A geochemical software program (PHREEQC) was used. Based on the analyses, PHREEQC appears the precipitation of a sequence of minerals. These results are confirmed by the mineralogical analyses (XRD results). The gradual evaporation process of brine showed that thenardite, gypsum, halite, and huntite are the feasible salts that could be extracted. Halite is the most abundant mineral along with the evaporation experiment of the two sebkhas.