Crystallization Properties of Schoenite in Ethanol-Water and Methanol-Water Mixed Solvents
软钾镁矾在乙醇-水和甲醇-水混合溶剂中的结晶特性

Using wet slag method,the solubilities of schoenite in ethanol-water and methanol-water systems were determined.With conductivity method,the metastable zone widths of schoenite were measured,and the influences of temperature,cooling rate and agitating rate on it also investigated.The results show that the higher proportion the ethanol or methanol in the mixed solvents,the smaller solubility the schoenite has.When the volume ratio of methanol or ethanol to water is 1:1,the solubility of schoenite nearly reach zero.Moreover,the crystalline area of K2SO4 in methanol-water solvent is bigger than that in ethanol-water solvent under the same solvent ratio.Under the present experimental conditions,the metastable zone width of schoenite is expanded from 0.40% to 1.48% with the cooling rate increasing from 15 to 35℃/h,decreasing from 1.54% to 1.04% along with the stirring rate increasing from 250 to 460 r/min,and changing from 1.61% to 1.24% when the temperature rises from 25℃ to 35℃.