Patent US2696426A successfully refreshed from Google Patents.
US2696426A
Expired / Lapsed
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Process for the preparation of iron oxide pigments
Assignee: Wyeth Holdings LLC
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Filing: 1951-05-04
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Granted: 1954-12-07
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Expires: 1971-05-04
Abstract
No abstract record available.
Inventors
- 👤 Guy C Marcot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:34
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/02; C01G49/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
77 words
A METHOD OF PRODUCING A CRYSTALLINE IRON OXIDE PIGMENT WHICH COMPRISES: FORMING AN AQUEOUS SOLUTION OF A SOLUBLE FERROUS SALT; FORMING AN AQUEOUS SOLUTION OF AN ALKALI METAL CARBONATE MORE THAN STOICHIOMETRICALLY EQUIVALENT TO SAID FERROUS SALT; ADDING SAID FERROUS SALT SOLUTION TO SAID CARBONATE SOLUTION AT A TEMPERATURE BELOW 45* C.; OXIDIZING THE FERROUS CONTENT OF THE MIXTURE BELOW 45* C.; AND HEATING THE SLURRY WHICH RESULTS TO ABOVE 80* C. UNTIL CONVERSION IS SUBSTANTIALLY COMPLETE.
Claim 2
Independent Claim
77 words
A METHOD OF PRODUCING A CRYSTALLINE IRON OXIDE PIGMENT WHICH COMPRISES: FORMING AN AQUEOUS SOLUTION OF A SOLUBLE FERROUS SALT; FORMING AN AQUEOUS SOLUTION OF AN ALKALI METAL CARBONATE MORE THAN STOICHIOMETRICALLY EQUIVALENT TO SAID FERROUS SALT; ADDING SAID FERROUS SALT SOLUTION TO SAID CARBONATE SOLUTION AT A TEMPERATURE BELOW 45* C.; OXIDIZING THE FERROUS CONTENT OF THE MIXTURE BELOW 45* C.; AND HEATING THE SLURRY WHICH RESULTS TO ABOVE 80* C. UNTIL CONVERSION IS SUBSTANTIALLY COMPLETE.
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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) | 1957-12-06 | 1958-06-07 | 1958-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-12-06 | 1962-06-07 | 1962-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-12-06 | 1966-06-07 | 1966-12-07 | $7700.00 | Window Closed / Lapsed |