TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The process comprises reacting a chloride of potassium with a magnesium sulfate in an aqueous alcoholic solution, with recycling of magnesium sulfate and production of hydrochloric acid. The recycling of magnesium is done by a reaction of sulfuric acid on resulting magnesium chloride with corresponding production of magnesium sulfate and hydrochloric acid. The reacting the source of water soluble potassium with the magnesium sulfate-containing substance in presence of the aqueous alcoholic solution is performed at 50-65 degrees C. The temperature of the reaction of sulfuric acid on the resulting magnesium chloride is 90-120 degrees C. The hydrochloric acid is collected as a solution of 15-32% hydrochloric acid in water. Preferred Components: The source of potassium is potassium chloride or carnallite.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The aqueous alcoholic solution comprises a low boiling alcohol, preferably methanol, propanol or ethanol. ACTIVITY - Fertilizer.    MECHANISM OF ACTION - None given.    EXAMPLE - Magnesium chloride hexahydrate (300 g) was treated with 96% sulfuric acid (175.8 g) in beaker (1 l). The temperature was raised to 120 degrees C and the operation was accompanied with the evolution of hydrochloric acid. Twice a 20 ml portion of water was added and distilled in order to complete the stripping of hydrochloric acid. The obtained residual solid was taken up with water (500 ml) in order to recrystallize the magnesium sulfate heptahydrate after evaporation of water (100 ml). After drying at 70 degrees C, a crop of magnesium sulfate heptahydrate (A1) was obtained. The mother liquor from this crystallization can be recycled in further operation. Potassium chloride (121 g) was dissolved in water (335 ml) at 60 degrees C in beaker (1.4 l) to obtain potassium chloride solution (B1). (A1) (200 g) was dissolved in water (142 ml) at 60 degrees C in a beaker (1 l). then warm methanol (40 degrees C) (230 ml) was added slowly with good stirring to the solution of magnesium sulfate. The warm methanolic solution of magnesium sulfate was poured into the warm (B1) rapidly with good stirring. There was a partial precipitation and the mixture was cooled at 0-5 degrees C. The crystalline mass was filtered, rinsed with methanol (600 ml) and dried at 100 degrees C, giving a crop of potassium sulfate (113 g).