Molten Carbonate Electrolytes: Physical Properties, Structure, and Mechanism of Electrical Conductance

Abstract

Results are presented of an investigation of the properties of surface tension, density, and electrical conductance for molten Li2CO3, Na2CO3, and K2CO3 and some mixtures in the temperature range of 750 to 1000 C. The surface tensions are approximately twice the values for the corresponding chlorides: the densities and electrical conductance are quite comparable to those of the chlorides. The ionic nature of the molten carbonates is examined from the physicochemical criteria based on these properties: and the mechanism of electrical transport is considered in the light of current theoretical concepts. Relative to Na2CO3 - K2CO3 mixtures, the surface tensions and partial molal volumes indicate but little deviations from the predictions for thermodynamically ideal mixtures. (Author)