Evaluation of interrelation of electrochemical properties and thermal storage capacity of the melt of crystal hydrates of inorganic substances on the basis of Na2S2O3·5H2O

Abstract

Research of conductivity of concentrated salt solutions are of great interest in connection with the structural changes in electrolytes. The heat storage properties of the mixture of sodium thiosulfate pentahydrate and sodium tellurate dihydrate were calculated. Firstly the coefficients of temperature dependence of heat capacity of sodium tellurate were calculated. Melting temperature of mixtures at ratios (50:1, 25:1, 10:1), which are equal to 349 K, 307 K, 326 K, were determined. The specific melting heat of mixtures was calculated. It was shown, that heat of fusion of mixture Na2S2O3·5H2O — Na2TeO4·2H2O (10:1) is maximal and equals to 238.5 kJ·kg-1. An analysis of the temperature dependence of the electrical conductivity was carried out. It showed the presence of high activity and mobility of tellurate-ions. It was shown that crystallization process is changed from quasi-equilibrium to the «explosive» at low temperatures ranging from T=318 K.