Process for producing potassium sulfate starting from kainite

Claim 1

A PROCESS FOR PRODUCING POTASIUM SULFATE FROM KAINITE WHICH COMPRISES THE STEPS OF: (A) COVERTING KAINITE INTO SOHOENITE WITH SULFATE MOTHER LIQUOR RECYCLED FROM STEP H AT A TEMPERATURE BETWEEN 35*C. AND 40*C. TO PRODUCE AN EQUILIBRIUM SOLUTION AND SCHOENITE, (B) SEPARATING SAID EQUILIBRIUM SOLUTION AND SCHOENITE, (C) SUSPENDING A PORTION OF SAID SCHOENITE IN SAID EQUILIBRIUM SOLUTION TO PRODUCE A SUSPENSION, (D) ADDING CALCIUM SULFATE AND SYNGENITE SEED CRYSTALS AT A TEMPERATURE BETWEEN ABOUT 35* AND 40*C. TO FORM A SYNGENITE PRECIPITATE, (E) SEPARATING OFF SAID SYNGENITE PRECIPITATE, (F) DISSOLVING SAID SYNGENITE WITH THE QUANTITY OF WATER, NECESSARY TO CONVERT THE REMAINDER OF SAID SCHOENITE TO POTASSIUM SULFATE TO PRODUCE A POTASSIUM SULFATE SOLUTION CONTAINING SOLID CALCIUM SULFATE, (G) SEPARATING THE CALCIUM SULFATE FROM THE POTASSIUM SULFATE SOLUTION, (H) LEACHING THE REMAINDER OF SAID SCHOENITE FROM STEP B WITH THE SEPARATED POTASSIUM SULFATE SOLUTION AT 48*C., TO OBTAIN POTASSIUM SULFATE AND A SULFATE MOTHER LIQUOR, AND RECYCLING THE SULFATE MOTHER LIQUOR TO SAID STEP (A).