Patent US3853490A successfully refreshed from Google Patents.
US3853490A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Granulation of potassium sulfate
Assignee: IMC Fertilizer Inc
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Filing: 1973-01-22
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Granted: 1974-12-10
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Expires: 1993-01-22
Abstract
Abstract Potassium sulfate crystals are granulated by first preparing a potassium sulfate feed material sized such as it is at least 50% -6 +65 mesh, 10% to 30% -200 mesh, with the remainder being -65 +200 mesh. The sized crystals are wetted to a moisture content of 7 to 12 percent by weight of the crystals. A small amount of a surface active agent such as disodium 4-dodecylated oxydibenzene sulfonate is incorporated in the admixture, and the mass granulated and dried in a rotating, tubular granular drier. Product temperature is maintained below a maximum of 550*F. and the maximum temperature of gases contacting the product is maintained below 1,200*F.
Inventors
- 👤 A Boeglin
- 👤 E Chowning
- 👤 S Tschappler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:53
CPC Classifications
C; C01; C01D; C01D5/00; C01D5/004; B; B01; B01J; B01J2/00; B01J2/12; C05; C05D; C05D1/00; C05D1/005
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
171 words
A METHOD FOR GRANULATING POTASSIUM SULFATE COMPRISING ESTABLISHING A MASS OF POTASSIUM SULFATE CRYSTALS CHARACTERIZED BY (1) CRYSTAL SIZE DISTRIBUTION OF AT LEAST 50 PERCENT BY WEIGHT -6+65 MESH, ABOUT 10 TO 30 PERCENT BY WEIGHT, -200 MESH, WITH THE REMAINDER BEING ESSENTIALLY -65 +200 MESH; (2) A MOISTURE CONTENT IN THE RANGE OF ABOUT 7 TO ABOUT 12 PERCENT BY WEIGHT OF THE CRYSTALS; AND (3) THE PRESENCE OF A SURFACE ACTIVE AGENT CAPABLE OF SUBSTANTIALLY ENCHANCING POTASSIUM SULFATE CRYSTAL GROWTH IN THE AMOUNT OF ABOUT 0.025 TO ABOUT 0.075 PERCENT BY WEIGHT OF THE CRYSTALS, ROLLING SAID MASS IN A CONFINED BED ON A SUBSTANTIALLY SMOOTH MOVING SURFACE TO FROM GRANULES, AND DRYING SAID GRANULES TO A MOISTURE CONTENT OF LESS THAN ABOUT 1 2 OF 1 PERCENT BY HEAT EXCHANGE BETWEEN SAID GRANULES AND HOT COMBUSTION GASES, THE MAXIMUM TEMPERATURE OF GASES IN CONTACT WITH SAID GRANULES BEING MAINTAINED AT LEAST THAN ABOUT 1,200*F., AND THE MAXIMUM TEMPERATURE REACHED IN THE DRYINNG STEP BEING MAINTAINED BELOW ABOUT 550*F.
Claim 2
Independent Claim
171 words
A METHOD FOR GRANULATING POTASSIUM SULFATE COMPRISING ESTABLISHING A MASS OF POTASSIUM SULFATE CRYSTALS CHARACTERIZED BY (1) CRYSTAL SIZE DISTRIBUTION OF AT LEAST 50 PERCENT BY WEIGHT -6+65 MESH, ABOUT 10 TO 30 PERCENT BY WEIGHT, -200 MESH, WITH THE REMAINDER BEING ESSENTIALLY -65 +200 MESH; (2) A MOISTURE CONTENT IN THE RANGE OF ABOUT 7 TO ABOUT 12 PERCENT BY WEIGHT OF THE CRYSTALS; AND (3) THE PRESENCE OF A SURFACE ACTIVE AGENT CAPABLE OF SUBSTANTIALLY ENCHANCING POTASSIUM SULFATE CRYSTAL GROWTH IN THE AMOUNT OF ABOUT 0.025 TO ABOUT 0.075 PERCENT BY WEIGHT OF THE CRYSTALS, ROLLING SAID MASS IN A CONFINED BED ON A SUBSTANTIALLY SMOOTH MOVING SURFACE TO FROM GRANULES, AND DRYING SAID GRANULES TO A MOISTURE CONTENT OF LESS THAN ABOUT 1 2 OF 1 PERCENT BY HEAT EXCHANGE BETWEEN SAID GRANULES AND HOT COMBUSTION GASES, THE MAXIMUM TEMPERATURE OF GASES IN CONTACT WITH SAID GRANULES BEING MAINTAINED AT LEAST THAN ABOUT 1,200*F., AND THE MAXIMUM TEMPERATURE REACHED IN THE DRYINNG STEP BEING MAINTAINED BELOW ABOUT 550*F.
Claim 3
Dependent Claim
30 words
The method in accordance with claim 1 in which said mass is subject to heat exchange with combustion gases at a temperature less than about 1200*F. during the granulation step.
Claim 4
Dependent Claim
28 words
The method in accordance with claim 2 in which said crystal mass contains moisture in the amount of about 7.5 to 9 percent by weight of the crystals.
Claim 5
Dependent Claim
27 words
The method in accordance with claim 3 in which said surface active agent is present in the amount of about 0.05 percent by weight of the crystals.
Claim 6
Dependent Claim
18 words
The method in accordance with claim 4 in which said surface active agent is disodium 4-dodecylated oxydibenzene sulfonate.
Claim 7
Dependent Claim
26 words
The method in accordance with claim 5 in which the moiSture content of said mass is derived from mother liquor from which potassium sulfate is crystallized.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |