Patent US3561919A successfully refreshed from Google Patents.
US3561919A
Expired / Lapsed
US
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Iron oxide-ferrite production process
Assignee: Pfizer Pigments Inc
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Filing: 1969-06-13
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Granted: 1971-02-09
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Expires: 1989-06-13
Abstract
Abstract PROCESS FOR THE PREPARATION OF SOFT AND HARD FERRITES FROM SYNTHETIC NON-MAGNETIC IRON OXIDE. PROCESS FOR MANUFACTURING FERRITES, OF LOW SILICA CONTENT DIRECTLY FROM THIS IRON OXIDE SCALE WITHOUT RESORT TO PURIFICATION STEPS TO REMOVE SILICA FROM THE IRON SOURCE MATERIAL. SCALE IS CALCINED IN THE PRESENCE OF FERROUS SULFATE HEPTAHYDRATE OR SULFURIC ACID OR A COMBINATION OF BOTH; THE SYNTHETIC NON-MAGNETIC IRON OXIDE PRODUCT IS THEN MILLED TO THE DESIRED FINENESS, COMBINED WITH OTHER FERRITE INGREDIENTS AND FORMED INTO FERRITES. SYNTHETIC ION OXIDE PRODUCT ALSO SUITABLE FOR USE IN ROUGES.
Inventors
- 👤 Joseph W Ayers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:07
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C01; C01G; C01G49/00; C01G49/02; C01G49/06; C01P; C01P2006/00; C01P2006/42; C01P2006/80
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1974-02-08 | 1974-08-10 | 1975-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-08 | 1978-08-10 | 1979-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-08 | 1982-08-10 | 1983-02-09 | $7700.00 | Window Closed / Lapsed |