US2689168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of gamma ferric oxide
Assignee: The General Electric Company PLC
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Filing: 1949-11-22
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Granted: 1954-09-14
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Expires: 1969-11-22
Abstract
No abstract record available.
Inventors
- 👤 Dovey Douglas Marshall
- 👤 Pitkin Wilfred Robarts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:41
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70652; C; C01; C01G; C01G49/00; C01G49/02; C01G49/06; Y; Y10; Y10T; Y10T428/00; Y10T428/29
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
140 words
A PROCESS FOR THE PRODUCTION OF GAMMA FERRIC OXIDE IN THE FORM OF A FINELY-DIVIDED CRYSTALLINE POWDER, WHICH COMPRISES THE STEPS OF HEATING COMMERCIAL ALPHA FERRIC OXIDE WHICH IS IN THE FORM OF SMALL CRYSTALS, OF DIAMETER NOT GREATER THAN ONE MICRON, TO A TEMPERATURE BETWEEN 275* C. AND 400* C. IN A REDUCING ATMOSPHERE UNTIL SUBSTANTIALLY COMPLETE CONVERSION TO FERROSOFERRIC OXIDE HAS TAKEN PLACE, COOLING TO BELOW 100* C. THE FERROSOFERRIC OXIDE THUS FORMED, THOROUGHLY DAMPENING THE COOLED FERROSOFERRIC OXIDE WITH WATER, OXIDIZING THE DAMPENED FERROSOFERRIC OXIDE BY HEATING IT IN AIR AT A TEMPERATURE BETWEEN 100* C. AND 350* C. TO OBTAIN SUBSTANTIALLY PURE GAMMA FERRIC OXIDE, THE RATE OF OXIDATION BEING CONTROLLED BY DAMPENING SO AS TO PREVENT AN EXOTHERMIC RISE OF THE TEMPERATURE OF THE FERROSOFERRIC OXIDE ABOVE 350* C., AND RECOVERING THE GAMMA FERRIC OXIDE.
Claim 2
Dependent Claim
140 words
A PROCESS FOR THE PRODUCTION OF GAMMA FERRIC OXIDE IN THE FORM OF A FINELY-DIVIDED CRYSTALLINE POWDER, WHICH COMPRISES THE STEPS OF HEATING COMMERCIAL ALPHA FERRIC OXIDE WHICH IS IN THE FORM OF SMALL CRYSTALS, OF DIAMETER NOT GREATER THAN ONE MICRON, TO A TEMPERATURE BETWEEN 275* C. AND 400* C. IN A REDUCING ATMOSPHERE UNTIL SUBSTANTIALLY COMPLETE CONVERSION TO FERROSOFERRIC OXIDE HAS TAKEN PLACE, COOLING TO BELOW 100* C. THE FERROSOFERRIC OXIDE THUS FORMED, THOROUGHLY DAMPENING THE COOLED FERROSOFERRIC OXIDE WITH WATER, OXIDIZING THE DAMPENED FERROSOFERRIC OXIDE BY HEATING IT IN AIR AT A TEMPERATURE BETWEEN 100* C. AND 350* C. TO OBTAIN SUBSTANTIALLY PURE GAMMA FERRIC OXIDE, THE RATE OF OXIDATION BEING CONTROLLED BY DAMPENING SO AS TO PREVENT AN EXOTHERMIC RISE OF THE TEMPERATURE OF THE FERROSOFERRIC OXIDE ABOVE 350* C., AND RECOVERING THE GAMMA FERRIC OXIDE.
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) | 1957-09-13 | 1958-03-15 | 1958-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-09-13 | 1962-03-15 | 1962-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-09-13 | 1966-03-15 | 1966-09-14 | $7700.00 | Window Closed / Lapsed |