US3599701A
Expired / Lapsed
US
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Crystallization method
Assignee: Kemanord AB
•
Filing: 1968-07-30
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Granted: 1971-08-17
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Expires: 1988-07-30
Abstract
Abstract This invention generally relates to a method for continuous crystallization of water soluble compounds by means of which rounded or spherical crystals are obtained and good regulation of the size and the size distribution of the crystals is achieved. The method is particularly suitable for crystallization from aqueous solutions substantially free from impurities.
Inventors
- 👤 Bengt Olof Pontus Mollerstedt
- 👤 Karl Gunnar Stig Johansson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:18
CPC Classifications
B; B01; B01D; B01D9/00; B01D9/0018; B01D9/0059; Y; Y10; Y10S; Y10S159/00; Y10S159/25; Y10S159/38
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
38 words
A method according to claim 1 wherein the amount of air injected in the crystallizing zone is maintained constant and the amount of water is controlled so that the slurry in the crystallizing zone has a constant concentration.
Claim 2
Dependent Claim
77 words
A method according to claim 1, wherein the concentrated crystal slurry withdrawn from the crystallizing zone is divided into two portions in the ratio of about 1:1-1:9, the larger portion being returned to the process where it is mixed with water and the smaller portion being transferred to a separation zone for the separation of the large crystals, from whence the substantially crystal free mother liquor is returned to the process for mixing with a crystal slurry.
Claim 3
Dependent Claim
33 words
A method according to claim 1 wherein the temperature of the slurry of crystals prior to introduction into the crystallization zone is equal to or slightly higher than the temperature in the crystallizer.
Claim 4
Dependent Claim
75 words
A method according to claim 1, wherein the concentrated crystal slurry withdrawn from the crystallizing zone is mixed with water and then divided into two portions in the ratio of about 1:1 -1:9, the larger portion being returned to the crystallizing zone and the smaller portion being transferred to a separating zone for the separation of crystals, from whence the substantially crystal-free mother liquor is returned to the process for mixing with a crystal slurry.
Claim 5
Dependent Claim
28 words
A method according to claim 1, wherein between about 2 and 20 percent of the crystals are dissolved by mixing said slurry with water in a mixing zone.
Claim 6
Dependent Claim
25 words
A method according to claim 1, wherein the crystal content in the slurry whiCh is removed from the crystallization zone is at least 10 percent.
Claim 7
Dependent Claim
25 words
A method according to claim 1, wherein the crystal content in the slurry which is removed from the crystallization zone is more than 20 percent.
Claim 8
Dependent Claim
20 words
A method according to claim 1, wherein the water is added as a nonsaturated aqueous solution of the crystallizing compound.
Claim 9
Dependent Claim
39 words
A method according to claim 9, wherein the amount of air injected in the crystallizing zone is maintained constant and the amount of water added is controlled so that the slurry in the crystallizing zone has a constant concentration.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-16 | 1975-02-15 | 1975-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-16 | 1979-02-15 | 1979-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-16 | 1983-02-15 | 1983-08-17 | $7700.00 | Window Closed / Lapsed |