US3650690A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Boric acid production
Assignee: Stauffer Chemical Co
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Filing: 1968-10-18
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Granted: 1972-03-21
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Expires: 1988-10-18
Abstract
Abstract Boric acid is produced by treating an alkali metal borate ore with concentrated sulfuric acid in an amount sufficient to provide an alkali metal to sulfur mole ratio of 1.5 to 2.5, contacting the so treated ore with superheated steam at temperatures of 100* to 500* C. to produce a gaseous boric acidcontaining effluent, removing the effluent and recovering the boric acid therefrom.
Inventors
- 👤 Jerome C Shiloff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:29
CPC Classifications
C; C01; C01B; C01B35/00; C01B35/06; C01B35/08; C01B35/10
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
18 words
A method as recited in claim 1 wherein said alkali metal borate ore is a sodium tetraborate ore.
Claim 2
Dependent Claim
14 words
A method as recited in claim 2 wherein said sodium tetraborate ore is kernite.
Claim 3
Dependent Claim
24 words
A method as recited in claim 1 wherein said reaction zone is maintained at a temperature of between about 100* and about 600* C.
Claim 4
Dependent Claim
24 words
A method as recited in claim 1 wherein said reaction zone is maintained at a temperature of between about 100* and about 400* C.
Claim 5
Dependent Claim
24 words
A method as recited in claim 1 wherein said reaction zone is maintained at a temperature of between about 150* and about 250* C.
Claim 6
Dependent Claim
25 words
A method as recited in claim 1 wherein said borate ore has a particle size of from about 100 to about 400 mesh screen size.
Claim 7
Dependent Claim
30 words
A method as recited in claim 5 wherein at least 80 percent of said borate ore has a particle size of from about 100 to about 150 mesh screen size.
Claim 8
Dependent Claim
21 words
A method as recited in claim 1 wherein said alkali metal to sulfur mole ratio is approximately 1.9 to approximately 2.1.
Claim 9
Dependent Claim
89 words
A method for producing boric acid as recited in claim 1 wherein said alkali metal borate ore is a sodium tetraborate ore having a particle size of from about 100 to about 200 mesh screen size, said concentrated sulfuric acid has an H2SO4 content of at least 90 percent, said concentrated sulfuric acid is used in an amount sufficient to provide an alkali metal to sulfur ratio of approximately 1.9, and said temperature is maintained within said reaction zone at a temperature of between about 100* and 400* C.
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) | 1975-03-21 | 1975-09-20 | 1976-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-21 | 1979-09-20 | 1980-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-21 | 1983-09-20 | 1984-03-21 | $7700.00 | Window Closed / Lapsed |