Abstract.1 The conversion of kainite and solution saturated after ore dissolving into schoenite has been studied under laboratory conditions within 293-333 К for 1 h. The highest conversion was found to be at 333 К for 1 h. Using Arrhenius equation the "apparent" activation energy was calculated. Its value shows the transition area of the conversion. The cooling and conversion were studied under various values of air mixing intensity. The air consumption was determined to achieve the highest conversion. Kainite conversion into schoenite in the saturated solution at approximately 333 К is followed by cooling via air bubbling. This approach allows to produce schoenite by a simple way without special expensive equipment.