The Viscosity of NaCl-LiCl and KCl-NaCl-LiCl Systems

Abstract

The viscosity of the fused salt systems NaCl-LiCl and KCl-NaCl-LiCl have been investigated as functions of both temperature and molar compositions by the damped oscillation method with platinum disc. The isotherms of viscosity against molar compositions were determined over extended temperature ranges for these system and the activation energy for viscous flow was calculated according to Eyring's theory.
The isotherms of viscosity of fused NaCl-LiCl system showed negative deviation from additivity of molar compositions and increased with an increasing NaCl content in the liquid mixture. The activation energy showed negative deviation from additivity.
In the KCl-NaCl-LiCl system, the isotherms of viscosity decreased with an increasing LiCl in the mixture and increased slightly with increasing KCl or NaCI. In the 20 mol% KCl-NaCl-LiCl and the 40 mol% KCI-NaCI-LiCl systems, the activation energy showed positive deviations and a maximum value was found for each system.
These deviations are caused by the interaction between different types of ion pairs in the liquid mixture.