Systems and methods of producing potassium sulfate

A system for producing potassium sulfate, the system comprising:

• a conversion unit for converting a mixed salts feed stream into a conversion end slurry, the mixed salts feed stream comprising at least one potassium-containing salt, at least one chloride-containing salt, at least one magnesium containing salt and at least one sulfate-containing salt and the conversion end slurry comprising schoenite;
• a flotation unit coupled to the conversion unit for separating the conversion end slurry into a schoenite slurry stream and a tailings slurry stream;
• a leaching unit coupled to the flotation unit for leaching the schoenite slurry stream to produce a mother liquor stream and a schoenite stream;
• and
• a solid-liquid separating unit coupled to the leaching unit for separating the schoenite stream into a leach end brine stream and a leached schoenite stream;
• a crystallization unit coupled to the leaching unit for leaching the leached schoenite stream with water to produce a potassium sulfate product stream comprising potassium sulfate and a crystallizer mother liquor stream comprising magnesium sulfate and potassium sulfate;
• wherein the crystallizer mother liquor stream is returned to the leaching unit to produce the mother liquor stream and the schoenite stream;
• and
• wherein the mother liquor stream is returned to the conversion unit for the conversion of the mixed salts feed stream into the conversion end slurry.

A system of producing potassium sulfate, the system comprising:

• a conversion unit for converting a mixed salts feed stream into a conversion end slurry, the mixed salts feed stream comprising at least one potassium-containing salt, at least one chloride-containing salt, at least one magnesium containing salt and at least one sulfate-containing salt and the conversion end slurry comprising schoenite;
• a flotation unit coupled to the conversion unit for separating the conversion end slurry into a schoenite slurry stream and a tailings slurry stream;
• a leaching unit coupled to the flotation unit for leaching the schoenite slurry stream to produce a mother liquor stream and a schoenite stream;
• a solid-liquid separating unit coupled to the leaching unit for separating the schoenite stream into a leach end brine stream and a leached schoenite stream;
• a crystallization unit coupled to the leaching unit for leaching the leached schoenite stream with water to produce a potassium sulfate product stream comprising potassium sulfate and a crystallizer mother liquor stream comprising magnesium sulfate and potassium sulfate;
• and
• a tailings unit for leaching the tailings slurry stream with a dilute brine stream to produce a tailings stream and a brine recycle stream, the brine recycle stream comprising potassium.