US2787528A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for purifying graphite
Assignee: Southwestern Graphite Co
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Filing: 1953-09-18
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Granted: 1957-04-02
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Expires: 1973-09-18
Abstract
No abstract record available.
Inventors
- 👤 Adrian C Dorenfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:46
CPC Classifications
C; C01; C01B; C01B32/00; C01B32/20; C01B32/21; C01B32/215
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
93 words
THE PROCESS OF PURIFYING GRAPHITE COMPRISING PREPARING AND HEATING A FIRST SLURRY OF IMPURE GRAPHITE AND SULPHURIC ACID OF A CONCENTRATION BETWEEN 25% AND 96%, HOLDING SAID SLURRY AT A TEMPERATURE ABOUT 95 DEGREES CENTRIGRADE FOR A PREDETERMINED TIME, SEPARATING THE FLUIDS IN SAID SLURRY FROM THE GRAPHITE, PREPARING AND HEATING A SECOND SLURRY OF PREVIOUSLY ACID TREATED GRPAHITE IN A WEAK CAUSTIC SOLUTION, THE CAUSTIC BEING ONE WHOSE SILICATE IS SOLUBLE IN WATER, HOLDING SAID SECOND SLURRY ABOVE 50*C. FOR AT LEAST FIVE MINUTES, AND FINALLY, SEPARATING THE GRAPHITE FROM THE FLUIDS.
Claim 2
Dependent Claim
93 words
THE PROCESS OF PURIFYING GRAPHITE COMPRISING PREPARING AND HEATING A FIRST SLURRY OF IMPURE GRAPHITE AND SULPHURIC ACID OF A CONCENTRATION BETWEEN 25% AND 96%, HOLDING SAID SLURRY AT A TEMPERATURE ABOUT 95 DEGREES CENTRIGRADE FOR A PREDETERMINED TIME, SEPARATING THE FLUIDS IN SAID SLURRY FROM THE GRAPHITE, PREPARING AND HEATING A SECOND SLURRY OF PREVIOUSLY ACID TREATED GRPAHITE IN A WEAK CAUSTIC SOLUTION, THE CAUSTIC BEING ONE WHOSE SILICATE IS SOLUBLE IN WATER, HOLDING SAID SECOND SLURRY ABOVE 50*C. FOR AT LEAST FIVE MINUTES, AND FINALLY, SEPARATING THE GRAPHITE FROM THE FLUIDS.
Claim 3
Dependent Claim
37 words
THE PROCESS DEFINED IN CLAIM 1 CHARACTERIZED BY THE ADDITIONAL STEPS OF TREATING THE PREVIOUSLY ACID AND CAUSTIC TREATED GRAPHITE IN A SOLUTION CONTAINING FREE FLUORIDE IONS, AND SEPARATING THE GRAPHITE FROM THE FLUIDS IN THE SOLUTION.
References Cited (Backward Citations)
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US1188936A
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Cited
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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) | 1960-04-01 | 1960-10-01 | 1961-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-04-01 | 1964-10-01 | 1965-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-04-01 | 1968-10-01 | 1969-04-02 | $7700.00 | Window Closed / Lapsed |