The electrical conductivity of concentrated KCI solutions as a function of temperature at constant pressure

Abstract

The electrical conductivity of concentrated KCI solutions from 3.35m to 8.2m has been studied as a function of temperature up to 300°C, and for 4.57m KCI solution as a function of pressure at 50°C, 150°C, 250°C, up to 2,450 p.s.i. The equivalent conductance of 3.35m and 4.57m KCI passes through a maximum at 285°C and 300°C respectively, and maxima for 6.4m and 8.2m KCI have been estimated at 360°C and 410°C respectively by an extrapolation technique . The temperature of the conductance maximum, T max, as a function of concentration passes through a minimum at ~ 2m KCI. The conductance maxima of the descending portion of the graph from 0 .001m up to ~ 2m KCI has been attributed to the increased degree of association arising from a drop in the dielectric constant of water at elevated temperatures . The conductance maxima for the ascending section of the graph up to 8.2m KCI has been attributed to the increased degree of association at the low liquidus densities associated with high temperatures; as has been proposed for some molten salts. The evidence presented in this thesis casts some doubt on the application of the Free Volume theory to temperature dependent conductance phenomena.