US4045543A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of potassium sulfate and hydrogen chloride
Assignee: Pennzoil Quaker State Co
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Filing: 1975-11-12
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Granted: 1977-08-30
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Expires: 1995-11-12
Abstract
Abstract Potassium sulfate (K 2 SO 4 ) is prepared by reaction of potassium chloride and sulfuric acid in an aqueous medium by initially removing evolved HCl in the gaseous form at temperatures of about 65°-120° C., then removing the remaining HCl as an HCl/water azeotrope at temperatures of about 90° to 110° C., restoring to the reaction mixture the amount of water removed with the azeotrope, and permitting the potassium sulfate to crystallize from the solution.
Inventors
- 👤 John B. Sardisco
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:40
CPC Classifications
C; C01; C01B; C01B7/00; C01B7/01; C01B7/03; C01B7/035; C01D; C01D5/00; C01D5/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
161 words
A method for the production of potassium sulfate and potassium hydrogen sulfate which comprises initially reacting potassium chloride and sulfuric acid in an aqueous medium at a temperature of about 65° to 120° C. under conditions to form hydrogen chloride and removing a portion of the hydrogen chloride from the reaction zone by gaseous evolution, thereafter subjecting the resulting aqueous solution to azeotropic distillation at temperatures in the range of from 90° to 110° C., and removing an HCl/water azeotrope until the remainder of the hydrogen chloride has been removed, and form a resulting aqueous slurry, thereafter adding to the resulting aqueous slurry an amount of water which is substantially equivalent to the amount of water removed with the azeotrope to again form an aqueous solution, cooling the aqueous solution to a temperature of about 30°-75° C., to allow a solid precipitate to crystallize from solution, and recovering the solid which comprises a mixture of potassium sulfate and potassium hydrogen sulfate.
Claim 2
Independent Claim
161 words
A method for the production of potassium sulfate and potassium hydrogen sulfate which comprises initially reacting potassium chloride and sulfuric acid in an aqueous medium at a temperature of about 65° to 120° C. under conditions to form hydrogen chloride and removing a portion of the hydrogen chloride from the reaction zone by gaseous evolution, thereafter subjecting the resulting aqueous solution to azeotropic distillation at temperatures in the range of from 90° to 110° C., and removing an HCl/water azeotrope until the remainder of the hydrogen chloride has been removed, and form a resulting aqueous slurry, thereafter adding to the resulting aqueous slurry an amount of water which is substantially equivalent to the amount of water removed with the azeotrope to again form an aqueous solution, cooling the aqueous solution to a temperature of about 30°-75° C., to allow a solid precipitate to crystallize from solution, and recovering the solid which comprises a mixture of potassium sulfate and potassium hydrogen sulfate.
Claim 3
Dependent Claim
17 words
A process according to claim 1 wherein the temperature in the initial step is about 90°-110° C.
Claim 4
Dependent Claim
52 words
A method according to claim 1 wherein the solid recovered is washed with an aqueous solution selected from the group consisting of water and an aqueous solution containing potassium sulfate to remove potassium hydrogen sulfate from the solid to provide a solid potassium sulfate and an aqueous solution containing potassium hydrogen sulfate.
Claim 5
Dependent Claim
213 words
A continuous procedure for the production of potassium sulfate which comprises reacting potassium chloride and sulfuric acid in an aqueous medium in an initial reaction step at a temperature of about 65° to 120° C. under conditions to form hydrogen chloride and removing a portion of the hydrogen chloride from the reaction zone by gaseous evolution, thereafter subjecting the resulting aqueous solution to azeotropic distillation at temperatures in the range of 90°-110° C while removing an HCl/water azeotrope and continuing removal of the azeotrope until the remainder of the hydrogen chloride has been removed; and form an aqueous slurry, thereafter adding to the aqueous slurry an amount of water which is substantially equivalent to the amount of water removed with the azeotrope to again form an aqueous solution, cooling the resulting solution to a temperature in the range of about 30°-75° C. to allow a solid precipitate to crystallize from solution, separating the solid precipitate from the solution, recycling the separated solution to the initial reaction step, washing the separated solid precipitate with a member selected from the group consisting of water and an aqueous solution containing potassium sulfate, to form a solid and a wash filtrate, recycling the wash filtrate to be initial reaction step and recovering the solid comprising potassium sulfate.
Claim 6
Dependent Claim
213 words
A continuous procedure for the production of potassium sulfate which comprises reacting potassium chloride and sulfuric acid in an aqueous medium in an initial reaction step at a temperature of about 65° to 120° C. under conditions to form hydrogen chloride and removing a portion of the hydrogen chloride from the reaction zone by gaseous evolution, thereafter subjecting the resulting aqueous solution to azeotropic distillation at temperatures in the range of 90°-110° C while removing an HCl/water azeotrope and continuing removal of the azeotrope until the remainder of the hydrogen chloride has been removed; and form an aqueous slurry, thereafter adding to the aqueous slurry an amount of water which is substantially equivalent to the amount of water removed with the azeotrope to again form an aqueous solution, cooling the resulting solution to a temperature in the range of about 30°-75° C. to allow a solid precipitate to crystallize from solution, separating the solid precipitate from the solution, recycling the separated solution to the initial reaction step, washing the separated solid precipitate with a member selected from the group consisting of water and an aqueous solution containing potassium sulfate, to form a solid and a wash filtrate, recycling the wash filtrate to be initial reaction step and recovering the solid comprising potassium sulfate.
Claim 7
Dependent Claim
20 words
A method according to claim 4 wherein the initial reaction step is conducted at a temperature of about 90°-110° C.
Claim 8
Dependent Claim
21 words
A method according to claim 4 wherein the separated solid precipitate is washed with an aqueous solution saturated with potassium sulfate.
References Cited (Backward Citations)
US995105A
Cited
US2816820A
Cited
US2902341A
Cited
GB1145390A
Cited
US3687639A
Cited
JPS4715454U
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-29 | 1981-02-28 | 1981-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-29 | 1985-02-28 | 1985-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-29 | 1989-02-28 | 1989-08-30 | $7700.00 | Window Closed / Lapsed |