Abstract: Screening analysis experiment,saturated brine dissolving and washing experiment，and flotation comparison experiment were carried out for studying carnallite with high content of calcium sulfate.It was found that calcium sulfate will enrich in the production of potassium chloride,which will cause a big impact on the quality of potassium chloride products.In carnallite with high content of calcium sulfate,calcium sulfate mainly concentrated in the small particles with size under 0.038 mm,which accounted for 4.84% of the total amount.If through mesh sieve,removal rate calcium sulfute could reach more than 61.82% and potassium loss rate was only 1.05%.Then the mass fraction of calcium sulfate in carnallite could be reduced to 1.4% below from 1.99% by using saturated brine to dissolve and wash it and the calcium sulfate in the brine could also be separated out due to common-ion effect and salting-out effect,so that the quality of brine could be also improved.Dissolving and washing of high calium ore in saturated brine can increase the mass fraction of KCl in final product to 90% or more and the process route of continuous industrial production of carnallite with high content of calcium sulfate was further obtained.

Key words: saturated brine, potassium chloride, calcium sulfate, carnallite