Method and system for the production of potassium sulfate from potassium chloride

1. A method for the production of potassium sulfate, comprising reacting a chloride of potassium with a magnesium sulfate in an aqueous alcoholic solution, with recycling of magnesium sulfate and production of hydrochloric acid, wherein 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.

2. The method as in claim 1 , where the temperature of the reaction of sulfuric acid on the resulting magnesium chloride is a range comprised between 90 and 120° C.

3. The method as in claim 1 , where hydrochloric acid is collected as a solution of about 15 to 32% HCl in water.

4. A method for the production of potassium sulfate comprising reacting a source of water soluble potassium with a magnesium sulfate-containing substance in presence of an aqueous alcoholic solution, wherein said reacting the source of water soluble potassium with the magnesium sulfate-containing substance in presence of the aqueous alcoholic solution is performed at a temperature in a range comprised between 50 and 65° C.

5. The method as in claim 4 , where the source of potassium is KCl.

6. The method as in claim 4 , where the source of potassium is carnallite.

7. The method as in claim 4 , where the aqueous alcoholic solution comprises a low boiling alcohol.

8. The method as in claim 4 , where the aqueous alcoholic solution comprises one of: methanol, propanol and ethanol.

9. A system for the production of potassium sulfate, comprising:

a first reactor for dissolving a water soluble potassium in water into a first solution;

a second reactor for dissolving magnesium sulfate hydrate in water and adding methanol into a second solution;

a third reactor, adapted to receive the first and the second solutions, mixed then under stirring and cool them down into a slurry;

a filter collecting and filtering the slurry from the third reactor; delivering, after rinsing of the solid part with methanol, chloride-free potassium sulfate, and a combined filtrate and rinsings;

a column receiving and distilling the combined filtrate and rinsings, delivering methanol back to the second reactor and to the filter and a concentrated solution of magnesium chloride;

a fourth reactor, adapted to receive the concentrated solution of magnesium chloride, which crystallizes upon cooling, and to treat the concentrate with sulfuric acid, delivering hydrochloric acid and a residual mass;

a collector, adapted to absorb the hydrochloric acid delivered form from the fourth reactor; and

a fifth reactor, adapted to collect and crystallise the residual mass from the fourth reactor, for recycling to the second reactor as magnesium sulfate heptahydrate.