Journal de thermodynamique et de catalyse
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Thermodynamic Models: Application to the Brines of Chotts in Algerian North-Eastern Sahara

Abdelaziz and Messaoud H

The Brines of chotts in Algerian Northeastern Sahara are highly concentrated solutions of mineral salts with a salinity that far exceeds that of the sea water (120 to 440 g/l). The first interpretation of data allows to specify the chemical facies of these brines form their chemical compositions. They have mainly a very marked sodic chlorinated character. Databases of the thermodynamic model PHREEQC v3 were used to determine the saturated state of the brines with respect to principal chemical species. They are more oversaturated with calcite than with gypsum. The saturated state compared to the halite is no longer reached. Indeed, we use the thermodynamic model PHREEQC v3 to calculate the mineral/solutions equilibria on the basis of different assumptions. The test of these assumptions shows that each one has its limits to simulate and control the thermodynamic behaviour of the brines.