Relationship between degree of melting point depression of calcium chloride hexahydrate melt and amount of additives in the melt

With a view to controlling the melting point and extending the temperature range for practical application of calcium chloride hexahydrate as a latent heat storage material, an attempt was made to derive an empirical equation by which to evaluate quantitatively the degree to which various additives depress its melting point (measured value, 302 K). The change in melting point relative to the amount of additive was measured for each of nine additives, and the ability of each additive to depress melting point was expressed numerically by use of a simple empirical equation. Based on the assumption that the depression of melting point results from the synergistic action of completely dissociated ions in the melt, the ability of each type of ion was quantified, and the values were employed in a simple method to calculate the degree of melting point depression.