The experimental determination of the brine crystallization sequence during isothermal evaporation is very time consuming. It requires a lot of difficult, tedious, lengthy and inaccurate analyses of liquid and solid phases. However if the phase diagram is known for a given system, application of the geometrical principles of phase rule allows to calculate equilibrium states and to attempt a more easy and accurate determination of the crystallization sequence of natural brine. This method was employed to simulate brine evaporation from Chott El Jerid (Tunisia) at 25 degrees C and to foresee the solid phases deposed during the process. (C) 2010 Elsevier BM. All rights reserved.