US3272595A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing magnetic acicular gamma iron oxide
Assignee: Individual
•
Filing: 1962-01-11
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Granted: 1966-09-13
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Expires: 1982-01-11
Abstract
No abstract record available.
Inventors
- 👤 Maho Charles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:05
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/0302; H01F1/0311; H01F1/0313; H01F1/0315; C; C01; C01G; C01G49/00; C01G49/02; C01G49/06; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70647; G11B5/70652; G11B5/70663; G11B5/70668; C01P; C01P2002/00; C01P2002/50; C01P2002/52; C01P2002/54; C01P2004/00; C01P2004/10; C01P2006/00; C01P2006/42
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
163 words
A METHOD FOR PREPARING MAGNETIC ACICULAR R-FE2O3 WITH IMPROVED THERMAL STABILITY FROM FE3O4 COMPRISING THE STEPS OF (A) PRECIPITATING AN IRON (II) SALT FROM AN AQUEOUS SOLUTION BY MEANS OF A STRONG BASE, SAID PRECIPITATION BEING CARRIED OUT IN THE PRESENCE OF A COMPOUND OF A METAL SELECTED FROM THE GROUP CONSISTING OF MOLYBDENUM, AND TUNGSTEN; (B) OXDIZING THE ACICULAR IRON (II) HYDROXIDE FORMED IN STEP A TO ACICULAR FE2O3.H2O NUCLEI BY BLOWING AIR THROUGH THE SUSPENSION OBTAINED IN STEP (A); (C) ADDING THE SUSPENSION OBTAINED STEP (B) TO A SOLUTION OF AN IRON (II) SALT AND TREATING THIS COMPOSITION WITH AIR IN THE PRESENCE OF IRON METAL, TO ENABLE THE FE2O3.H2O NUCLEI TO GROW; (D) SEPARATING AND DRYING THE ACICULAR FE2O3.H2O PARTICLES OBTAINED IN STEP (C); (E) DEHYDRATING THE ACICULAR FE2O3.H2O WHILST HEATING AND REDUCING IT BETWEEN 300 AND 450*C. TO ACICULAR FE3O4; AND (F) OXIDIZING AT 300-400*C. THE FE3O4 TO MAGNETIC ACICULAR R-FE2O3 BY MEANS OF A GAS CONTAINING FREE OXYGEN.
Claim 2
Independent Claim
163 words
A METHOD FOR PREPARING MAGNETIC ACICULAR R-FE2O3 WITH IMPROVED THERMAL STABILITY FROM FE3O4 COMPRISING THE STEPS OF (A) PRECIPITATING AN IRON (II) SALT FROM AN AQUEOUS SOLUTION BY MEANS OF A STRONG BASE, SAID PRECIPITATION BEING CARRIED OUT IN THE PRESENCE OF A COMPOUND OF A METAL SELECTED FROM THE GROUP CONSISTING OF MOLYBDENUM, AND TUNGSTEN; (B) OXDIZING THE ACICULAR IRON (II) HYDROXIDE FORMED IN STEP A TO ACICULAR FE2O3.H2O NUCLEI BY BLOWING AIR THROUGH THE SUSPENSION OBTAINED IN STEP (A); (C) ADDING THE SUSPENSION OBTAINED STEP (B) TO A SOLUTION OF AN IRON (II) SALT AND TREATING THIS COMPOSITION WITH AIR IN THE PRESENCE OF IRON METAL, TO ENABLE THE FE2O3.H2O NUCLEI TO GROW; (D) SEPARATING AND DRYING THE ACICULAR FE2O3.H2O PARTICLES OBTAINED IN STEP (C); (E) DEHYDRATING THE ACICULAR FE2O3.H2O WHILST HEATING AND REDUCING IT BETWEEN 300 AND 450*C. TO ACICULAR FE3O4; AND (F) OXIDIZING AT 300-400*C. THE FE3O4 TO MAGNETIC ACICULAR R-FE2O3 BY MEANS OF A GAS CONTAINING FREE OXYGEN.
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) | 1969-09-12 | 1970-03-14 | 1970-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-09-12 | 1974-03-14 | 1974-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-09-12 | 1978-03-14 | 1978-09-13 | $7700.00 | Window Closed / Lapsed |