Process for producing potassium hydroxide and potassium sulfate from sodium sulfate
AssigneeAirborne Industrial Minerals Inc.
InventorRobin Phinney
Life of this patent
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Abstract
There is disclosed a process for producing a potassium sulfate electrochemically. The process involves the use of sodium sulfate which is electrolyzed in an electrolytic cell and which results in the production of sodium hydroxide and ammonium sulfate. The process carried out in a two or three-compartment electrolytic cell and the ammonium sulfate is converted by ammoniation and treatment of the ammoniated mixture with potassium chloride to produce potassium sulfate. Potassium sulfate may then also undergo electrochemical treatment to produce potassium hydroxide and ammonium sulfate.
Claims18
A process for producing potassium sulfate in an electrolytic cell, comprising the steps of:
- passing a solution of sodium sulfate through a central compartment of an electrolytic cell having a cathode compartment and an anode compartment separated from the central compartment by a cation selective ion exchange membrane and an anion selective ion exchange membrane, respectively;
- passing a catholyte through the cathode compartment and an anolyte through the anode compartment;
- passing a direct electric current between an anode and a cathode located in the anode compartment and the cathode compartment, respectively, thus producing sodium hydroxide in the cathode compartment and sulfuric acid in the anode compartment;
- generating an acid ammonium sulfate;
- elevating the pH of the ammonium sulfate to a substantially neutral pH;
- introducing a potassium chloride;
- and
- precipitating potassium sulfate.
A process for producing potassium hydroxide and potassium sulfate, said process comprising the steps of:
- (a) providing a first and a second three-compartment electrolytic cell, each cell having a cathode compartment and an anode compartment separated from a central compartment by a cation selective ion exchange membrane and anion selective ion exchange membrane;
- (b) passing a solution of sodium sulfate through said central compartment;
- (c) passing a catholyte through said cathode compartment and an anolyte through said anode compartment of said first three-compartment electrolytic cell;
- (d) passing a direct current between an anode and a cathode located in said anode compartment and said cathode compartment, respectively, to produce sodium hydroxide in said cathode compartment and sulfuric acid in said anode compartment;
- (e) generating ammonium sulfate;
- (f) elevating the pH of said ammonium sulfate;
- (g) introducing potassium chloride into said ammonium sulfate;
- (h) forming potassium sulfate;
- (i) feeding a solution of said potassium sulfate into said central compartment of a second three-compartment electrolytic cell;
- (j) elevating the pH of said potassium sulfate;
- and
- (k) forming potassium hydroxide.
A process for producing potassium sulfate in an electrolytic cell, comprising the steps of:
- passing a solution of potassium sulfate through an electrolytic cell having a cathode compartment and an anode compartment separated by an ion exchange membrane;
- passing a direct current between said cathode and said anode to produce potassium hydroxide and a mixed brine of potassium bisulfate and sulfuric acid;
- mixing said mixed brine of potassium bisulfate and sulfuric acid with potassium chloride to produce a mixture;
- elevating the pH of the mixture;
- introducing a potassium chloride into the mixture;
- and
- precipitating potassium sulfate.
Dependencies are inferred from the claim text.