US 4,215,100 AGranted

Method of producing potassium sulfate

OwnerIgor D. Sokolov, Vera A. Ostanina +4inventors

InventorsIgor D. Sokolov, Vera A. Ostanina, Jury S. Safrygin, Tatyana I. Rutkovskaya, Nina V. Antonova, Rakhil E. Naginskaya

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Abstract

A method of producing potassium sulfate consists in conversion of sodium sulfate with potassium chloride in an aqueous medium to yield glaserite and a glaserite solution. Then, the glaserite is decomposed with potassium chloride in water to obtain potassium sulfate and a sulfate solution which is returned to the first stage of conversion. The glaserite solution is cooled at temperatures ranging from +3.degree. to -8.degree. C., whereby mirabilite and a chloride solution are formed, the latter being evaporated to obtain sodium chloride and a concentrated chloride solution. Finally, the concentrated chloride solution is mixed with mirabilite, and the resulting suspension is delivered to the first stage of conversion of sodium sulfate with potassium chloride. The proposed method permits producing high-quality potassium sulfate with full utilization of the return solutions. The yield of potassium sulfate reaches 98.6% at a K.sub.2 O content of up to 53% by weight.

Claims1

Dependent claims

A cyclic method of producing potassium sulfate consisting of the steps of

(1) subjecting sodium sulfate to conversion with potassium chloride in an aqueous medium to yield a precipitate of K.sub.6 Na.sub.2 (SO.sub.4).sub.4 and a first mother liquor;
(2) subjecting the precipitated K.sub.6 Na.sub.2 (SO.sub.4).sub.4 to conversion with aqueous potassium chloride to yield a precipitate of K.sub.2 SO.sub.4 and a second mother liquor;
(3) returning said second mother liquor to step (1);
(4) cooling said first mother liquor from step (1) at temperatures ranging from +3.degree. to -8.degree. C. to yield a precipitate of Na.sub.2 SO.sub.4.10H.sub.2 O and a third mother liquor;
(5) evaporating said third mother liquor from step (4) to obtain solid sodium chloride and a fourth mother liquor;
(6) mixing said Na.sub.2 SO.sub.4.10H.sub.2 O from step (4) with said fourth mother liquor from step (5) to produce a suspension of K.sub.6 Na.sub.2 (SO.sub.4).sub.4 ;
and
(7) returning the suspension of K.sub.6 Na.sub.2 (SO.sub.4).sub.4 from step (6) to the aqueous medium in step (1).

5 more elements

Dependencies are inferred from the claim text.