US2812245A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sodium sulfide recovery
Assignee: FMC Corp
•
Filing: 1954-02-15
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Granted: 1957-11-05
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Expires: 1974-02-15
Abstract
No abstract record available.
Inventors
- 👤 George S Haines
- 👤 Frank D Heindel
- 👤 Roy T Osborne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:48
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/22; C01B17/36; C01P; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
58 words
THE METHOD OF SEPARATING AND RECOVERING SODIUM SULFIDE FROM AN AQUEOUS SOLUTION CONTAINING SUBSTANTIAL PROPORTIONS OF SODIUM SULFIDE AND SODIUM HYDROXIDE, COMPRISING: EVAPORATING THE SODIUM TO A SODIUM HYDROXIDE CONCENTRATION WITHIN THE RANGE OF ABOUT 30 TO 50 WT. PERCENT; COOLING THE SOLUTION SUFFICIENTLY TO EFFECT SUBSTANTIAL CRYSTALLIZATION OF SODIUM SULFIDE; AND SEPARATING THE CRYSTALS FROM THE SOLUTION.
Claim 2
Independent Claim
58 words
THE METHOD OF SEPARATING AND RECOVERING SODIUM SULFIDE FROM AN AQUEOUS SOLUTION CONTAINING SUBSTANTIAL PROPORTIONS OF SODIUM SULFIDE AND SODIUM HYDROXIDE, COMPRISING: EVAPORATING THE SODIUM TO A SODIUM HYDROXIDE CONCENTRATION WITHIN THE RANGE OF ABOUT 30 TO 50 WT. PERCENT; COOLING THE SOLUTION SUFFICIENTLY TO EFFECT SUBSTANTIAL CRYSTALLIZATION OF SODIUM SULFIDE; AND SEPARATING THE CRYSTALS FROM THE SOLUTION.
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) | 1960-11-04 | 1961-05-06 | 1961-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-11-04 | 1965-05-06 | 1965-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-11-04 | 1969-05-06 | 1969-11-05 | $7700.00 | Window Closed / Lapsed |