Abstract: 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.

Key words: potassium sulfate, sodium sulfate, methanol, salting-out