Explosivity Conditions of Aqueous Solutions

Régis Thiery (1) , Lionel Mercury (2)

1 LMV - Laboratoire Magmas et Volcans
2 ISTO - Institut des Sciences de la Terre d'Orléans

This paper focuses on the conditions for explosive boiling and gas exsolution of aqueous solutions from a thermodynamic point of view. Indeed, the kinetic nature of these processes, hence their explosivity, can be assessed by considering their relation with the spinodal curve of these liquids. First, the concepts of mechanical and diffusion spinodals are briefly described, which allows us to introduce the notions of superspinodal (explosive) transformations and subspinodal (non-explosive) ones. Then, a quantitative study of spinodal curves is attempted for the binary systems H2O–CO2 and H2O–NaCl using equations of state having a strong physical basis. It is shown that dissolved gaseous components and electrolytes have an antagonist effect: dissolved volatiles (like CO2) tend to shift the superspinodal region towards lower temperatures, whereas electrolytes (like NaCl) tend to extend the metastable field towards higher temperatures.

Mots clés: Metastability · Equation of state · Spinodal · Carbon dioxide · Sodium chloride · Supersaturation

Domaines: Géochimie; Milieux et Changements globaux

Régis Thiery, Lionel Mercury. Explosivity Conditions of Aqueous Solutions. Journal of Solution Chemistry, 2009, 38 (7), pp.893-905. ⟨10.1007/s10953-009-9417-0⟩. ⟨insu-00403838⟩