Patent US887826A successfully refreshed from Google Patents.
US4244698A
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Method for drying magnesium sulfate
Assignee: Dow Chemical Co
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Filing: 1978-05-02
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Granted: 1981-01-13
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Expires: 1998-05-02
Abstract
Abstract A method of drying hydrated crystalline magnesium sulfate to reduce its surface moisture content is disclosed. The method comprises: (a) fluidizing a bed of hydrated crystalline magnesium sulfate particles by continuously passing a heated gaseous medium in a generally upwardly direction through the particles at a superficial velocity at least sufficient to maintain turbulent fluidization and mixing of the particles throughout the bed; (b) transferring a dispersed form of hydrated crystalline magnesium sulfate to be dried into the fluidized bed; (c) maintaining the amount of crystalline magnesium sulfate within the fluidized bed at a constant depth; (d) controlling the temperature and relative humidity of the heated gaseous medium to maintain a bed temperature and humidity sufficient to vaporize at least a portion of the surface moisture from the hydrated crystalline magnesium sulfate without removing waters of hydration; and (e) removing dried hydrated crystalline magnesium sulfate from the bed.
Inventors
- 👤 Robert J. King
- 👤 Herbert A. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:53
CPC Classifications
C; C01; C01F; C01F5/00; C01F5/40; F; F26; F26B; F26B3/00; F26B3/02; F26B3/06; F26B3/08
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
159 words
A method of drying hydrated crystalline magnesium sulfate to reduce its surface moisture content comprising: (a) fluidizing a bed of hydrated crystalline magnesium sulfate particles by continuously passing a heated gaseous medium in a generally upwardly direction through the particles at a superficial velocity at least sufficient to maintain turbulent fluidization and mixing of the particles throughout the bed; (b) transferring hydrated crystalline magnesium sulfate to be dried into the bed of particles from a crystal feeding means, said magnesium sulfate to be dried being in a dispersed form; (c) controlling the amount of hydrated crystalline magnesium sulfate within the bed to maintain a constant bed depth; (d) controlling the temperature and relative humidity of the heated gaseous medium to maintain a bed temperature and humidity sufficient to vaporize at least a portion of the surface moisture from the hydrated crystalline magnesium sulfate without removing waters of hydration; and (e) removing dried hydrated crystalline magnesium sulfate from the bed.
Claim 2
Independent Claim
159 words
A method of drying hydrated crystalline magnesium sulfate to reduce its surface moisture content comprising: (a) fluidizing a bed of hydrated crystalline magnesium sulfate particles by continuously passing a heated gaseous medium in a generally upwardly direction through the particles at a superficial velocity at least sufficient to maintain turbulent fluidization and mixing of the particles throughout the bed; (b) transferring hydrated crystalline magnesium sulfate to be dried into the bed of particles from a crystal feeding means, said magnesium sulfate to be dried being in a dispersed form; (c) controlling the amount of hydrated crystalline magnesium sulfate within the bed to maintain a constant bed depth; (d) controlling the temperature and relative humidity of the heated gaseous medium to maintain a bed temperature and humidity sufficient to vaporize at least a portion of the surface moisture from the hydrated crystalline magnesium sulfate without removing waters of hydration; and (e) removing dried hydrated crystalline magnesium sulfate from the bed.
Claim 3
Dependent Claim
47 words
The method of claim 1 wherein the temperature and relative humidity of the gaseous medium are controlled to maintain a partial water vapor pressure in the gaseous medium less than the water vapor pressure present at the surface of the hydrated crystalline magnesium sulfate within the bed.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein the gaseous medium is air.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein the superficial velocity is at least 2 foot per second.
Claim 6
Dependent Claim
19 words
The method of claim 1 wherein the superficial velocity is from about 3 to about 5 feet per second.
Claim 7
Dependent Claim
19 words
The method of claim 1 wherein the superficial velocity is from about 3 to about 4 feet per second.
Claim 8
Dependent Claim
18 words
The method of claim 1 wherein substantially all the surface moisture is vaporized without removing waters of hydration.
Claim 9
Dependent Claim
26 words
The method of claim 1 wherein the temperature of the heated gaseous medium is controlled to maintain a bed temperature of less than about 48° C.
Claim 10
Dependent Claim
28 words
The method of claim 1 wherein the temperature of the heated gaseous medium is controlled to maintain a bed temperature of from about 20° to about 45° C.
Claim 11
Dependent Claim
28 words
The method of claim 1 wherein the temperature of the heated gaseous medium is controlled to maintain a bed temperature of from about 40° to about 45° C.
Claim 12
Dependent Claim
28 words
The method of claim 1 wherein the hydrated crystalline magnesium sulfate to be dried has a surface moisture content of less than about 10 percent by weight water.
Claim 13
Dependent Claim
30 words
The method of claim 11 wherein the hydrated crystalline magnesium sulfate to be dried has a surface moisture content of from about 3 to about 6 percent by weight water.
Claim 14
Dependent Claim
23 words
The method of claim 1 wherein the magnesium sulfate to be dried has a particle size of about 3 to about 70 mesh.
Claim 15
Dependent Claim
19 words
The method of claim 13 wherein the hydrated crystalline magnesium sulfate removed from the bed is substantially uniformly dried.
Claim 16
Dependent Claim
13 words
The method of claim 1 wherein the magnesium sulfate is magnesium sulfate heptahydrate.
Claim 17
Dependent Claim
13 words
The method of claim 8 wherein the magnesium sulfate is magnesium sulfate heptahydrate.
Claim 18
Dependent Claim
13 words
The method of claim 13 wherein the magnesium sulfate is magnesium sulfate heptahydrate.
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) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |