改进的甲醇盐析法分离钾钠混盐溶液制备硫酸钾

Preparation of potassium sulphate from separation of mixed solution of potassium and sodium salts with improved methanol salting-out method

将沉淀法与甲醇盐析法相结合,用于从硫酸钾硫酸钠混合饱和溶液中分离提取硫酸钾。重点研究了参与复分解反应的沉淀剂种类和所添加量以及甲醇的用量对硫酸钾纯度和收率的影响。实验结果表明,选择氯化钾为沉淀剂,n(氯化钾)∶n(硫酸钠)=0.6,甲醇的体积分数为60%,得到硫酸钾粗品的纯度为76.1%,收率可达93.8%。采用低温重结晶法提纯,可将硫酸钾纯度提高到99.9%,超过了工业硫酸钾一级产品质量标准。

The process of separating and extracting potassium sulphate from the mixed solution of potassium sulphate and sodium sulphate by combining the precipitation method with methanol salting-out method was studied.The effects of different operation conditions including the variety and additive amounts of precipitator,as well as the additive amount of methanol on the purity and yield of potassium sulphate were intensively investigated.Experimental results show that the yield and purity of coarse potassium sulfate can be 93.8% and 76.1% respectively under conditions as follows：taking potassium chloride as the precipitator,the amount-of-substance ratio of potassium chloride to sodium sulfate was 0.6,and volume fraction of methanol was 60%.Through the low temperature recrystallization process,the purity of potassium sulfate can reach up to 99.9%,which is higher than the purity of the first level product required in Industrial Potassium Sulphate Standard.