Research of Crystallization Thermodynamics and Metastable Zone Width of Anhydrous Sodium Sulfate

The crystallization thermodynamics of sodium sulfate was investigated. The solubility and ultra-solubility of sodium sulfate were measured with balance method to determine Metastable Zone Width(MSZW). The effect of different cooling rate and agitating rate on MSZW were also investigated. The nuclear equation and nucleation order of sodium sulfate as a function of supersaturation were found using the classical nucleation theory based approach of Nyvlt. Surface entropy factor was obtained under cooling crystallization. Experimental results show that the solubility increases with the increase of temperature. When the temperature continues to rise, there is a slow downward trend. MSZW becomes wider with the increase of cooling rate and becomes wider with the decrease of agitating rate.