Electrical Conductivity and Phase Transitions of Calcium Nitrate + Ammonium Nitrate + Water Mixtures

The electrical conductivity of liquid xCa(NO3)2·zH2O + (1 − x)NH4NO3 mixtures was measured as a function of temperature over the whole composition range, where 0.3 < x < 1.0 and 2.5 < z < 8.0. A new assessment and experimental confirmation of quasi-crystal theory of molten salts was made using electrical conductivity measurements as a suitable tool to show the difference between aqueous solutions and aqueous molten salt systems. Also, the influence of the electrolyte and water concentration on transport properties of the mixture was investigated. Because of possible applications of such systems for the heat transfer and energy storage, differential scanning calorimetry (DSC) was used to investigate the phase equilibrium in calcium nitrate tetrahydrate + ammonium nitrate mixtures. Prior to these measurements, thermal properties of pure calcium nitrate tetrahydrate and ammonium nitrate were reinvestigated: new experimental results were obtained because of existing literature discrepancies on pure components.