Nucleation by the Borax of Dispersed Sodium Sulfate, Possible Application in Heat Storage.

The crystallization of droplets of aqueous solutions of Na//2SO//4 (0. 9 mole Na//2SO//4; 10 moles (H//2O) and an excess of solid Na//2B//4O//7 10 H//2O, dispersed within an emulsifying medium has been studied by differential scanning calorimetry. Two maxima of crystallization are observed at plus 7 degree C and minus 2. 5 degree C (without borax, the crystallization occurs around minus 41 degree C). Between the first and thirtieth cooling and heating cycles, an increase of about 15% of the calorific energy released during the crystallization has been found. This type of nucleation process could be of interest in the field of heat storage.