Study on the Process of Potassium Sulfate Production from Lop Nur Salt Lake Brine Resource

Lop Nur salt Lake is the largest potassium brine deposits discovered in China. Its brine is a kind of magnesium sulfate sub-type brine and can be used to produce potassium sulfate fertilizer. In this paper, response to the feature of various potassium salts in brine evaporation and crystallization product and the great variety with evaporation temperature, the potassium sulfate production process was studied in detail. The mixed salts were pre-conversed and post-floated to form schoenite with the desirable potassium grade. In view of the natural conditions of severe water shortage in Lop Nur, camallite from post-stage of brine evaporation was decomposed creatively by low-magnesium saturated brine to produce coarse potassium chloride. Eventually, conversion experiment was carried out to produce potassium sulfate by adding water into schoenite and coarse potassium chloride. Raw material ratio, water volume, conversion time, conversion temperature, stirring intensity and other conditions was tested and determined. Optimized product of superior quality for agricultural use, with 57.54% conversion rate and 43.27% potassium sulfate, was achieved.