软钾镁矾在乙醇-水和甲醇-水混合溶剂中的结晶特性

采用湿渣法系统地测定了软钾镁矾在乙醇-水和甲醇-水混合溶剂中的相平衡数据，利用电导率法确定了其在水中的超溶解度及结晶介稳区，考察了温度、搅拌速率和降温速率对介稳区的影响. 结果表明，35℃下，软钾镁矾在两混合溶剂中的溶解度随其中乙醇和甲醇比例增大而减小，当乙醇:水或甲醇:水为1:1(j)时，软钾镁矾溶解度接近0，且相同配比的混合溶剂中，甲醇-水溶液中K2SO4的结晶区比乙醇-水溶液中大；在实验范围内，软钾镁矾的介稳区宽度随降温速率由15℃/h增至35℃/h而由0.40%增至1.48%(w，以软钾镁矾计，下同)，随搅拌速率由250 r/min增至460 r/min而由1.54%降至1.04%，随温度由25℃升至35℃而由1.61%降至1.24%.

Crystallization Properties of Schoenite in Ethanol-Water and Methanol-Water Mixed Solvents

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℃.