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 10:21
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.
References Cited (Backward Citations)
US3049419A
Cited
US3032408A
Cited
US3085870A
Cited
US3348938A
Cited
US3271106A
Cited
US3317307A
Cited
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 |