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US3845198A Expired / Lapsed US ⏱️ 0.0 years remaining

Acicular gamma iron oxide process

Assignee: Bell and Howell Co
•
Filing: 1972-05-03
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Granted: 1974-10-29
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Expires: 1992-05-03
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Abstract

Abstract 1. IN A PROCESS FOR THE PREPARATION OF ACICULAR, MAGNETIC Y-FE2O3 BY REACTION OF PRECURSOR A-FEOOH TO FE3O4 FOLLOWED BY OXIDATION TO SAID Y-FE2O3, WHEREIN SAID PRECURSOR A-FEOOH IS PREPARD BY OXIDIZING FERROUS ION IN AN ACIDIC CRYSTAL GROWTH LIQUID SOLUTION, IN THE PRESENCE OF SEED CRYSTALS OF A-FEOOH ADDED THERETO, WHILE ADDING ALKALI TO SAID ACIDIC CRYSTALS GROWTH SOLUTION TO PRECIPITATE SAID PRECURSOR A-FEOOH, SAID SEED CRYSTALS BEING PREPARED BY OXIDATION OF FERROUS ION IN A SEED PREPARATION LIQUID SOLUTION CONTAINING ALKALI, THE IMPROVEMENT, WHEREIN (A) SAID SEED CRYSTALS ARE PREPARED AT A TEMPERATURE LOWER THAN 50*C., (B) SAID SEED PREPARATION SOLUTION CONTAINS AN AMOUNT OF ALKALI AT LEAST 15% IN EXCESS OF A STOICHIOMETRIC AMOUNT REQUIRED FOR OXIDATIVE CONVERSION OF SAID FERROUS ION TO FERRIC ION AND (C) ACID IS ADDED TO SAID SEED PREPARATION SOLUTION AFTER FULL OXIDATIVE PREPARATION OF SAID SEED CRYSTALS, BUT BEFORE ADDITION OF SAID SEED CRYSTALS TO SAID CRYSTAL GROWTH SOLUTION, TO LOWER THE PH OF SAID SEED PREPARATION SOLUTION TO 2-5.

Inventors

  • 👤 G Marcot

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-26 15:11
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; G11B5/70647; C01P; C01P2004/00; C01P2004/10; C01P2004/54; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/10; C01P2006/42

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 168 words
IN A PROCESS FOR THE PREPARATION OF ACICULAR, MAGNETIC Y-FE2O3 BY REACTION OF PRECURSOR A-FEOOH TO FE3O4 FOLLOWED BY OXIDATION TO SAID Y-FE2O3, WHEREIN SAID PRECURSOR A-FEOOH IS PREPARD BY OXIDIZING FERROUS ION IN AN ACIDIC CRYSTAL GROWTH LIQUID SOLUTION, IN THE PRESENCE OF SEED CRYSTALS OF A-FEOOH ADDED THERETO, WHILE ADDING ALKALI TO SAID ACIDIC CRYSTALS GROWTH SOLUTION TO PRECIPITATE SAID PRECURSOR A-FEOOH, SAID SEED CRYSTALS BEING PREPARED BY OXIDATION OF FERROUS ION IN A SEED PREPARATION LIQUID SOLUTION CONTAINING ALKALI, THE IMPROVEMENT, WHEREIN (A) SAID SEED CRYSTALS ARE PREPARED AT A TEMPERATURE LOWER THAN 50*C., (B) SAID SEED PREPARATION SOLUTION CONTAINS AN AMOUNT OF ALKALI AT LEAST 15% IN EXCESS OF A STOICHIOMETRIC AMOUNT REQUIRED FOR OXIDATIVE CONVERSION OF SAID FERROUS ION TO FERRIC ION AND (C) ACID IS ADDED TO SAID SEED PREPARATION SOLUTION AFTER FULL OXIDATIVE PREPARATION OF SAID SEED CRYSTALS, BUT BEFORE ADDITION OF SAID SEED CRYSTALS TO SAID CRYSTAL GROWTH SOLUTION, TO LOWER THE PH OF SAID SEED PREPARATION SOLUTION TO 2-5.
Claim 2
Dependent Claim 168 words
IN A PROCESS FOR THE PREPARATION OF ACICULAR, MAGNETIC Y-FE2O3 BY REACTION OF PRECURSOR A-FEOOH TO FE3O4 FOLLOWED BY OXIDATION TO SAID Y-FE2O3, WHEREIN SAID PRECURSOR A-FEOOH IS PREPARD BY OXIDIZING FERROUS ION IN AN ACIDIC CRYSTAL GROWTH LIQUID SOLUTION, IN THE PRESENCE OF SEED CRYSTALS OF A-FEOOH ADDED THERETO, WHILE ADDING ALKALI TO SAID ACIDIC CRYSTALS GROWTH SOLUTION TO PRECIPITATE SAID PRECURSOR A-FEOOH, SAID SEED CRYSTALS BEING PREPARED BY OXIDATION OF FERROUS ION IN A SEED PREPARATION LIQUID SOLUTION CONTAINING ALKALI, THE IMPROVEMENT, WHEREIN (A) SAID SEED CRYSTALS ARE PREPARED AT A TEMPERATURE LOWER THAN 50*C., (B) SAID SEED PREPARATION SOLUTION CONTAINS AN AMOUNT OF ALKALI AT LEAST 15% IN EXCESS OF A STOICHIOMETRIC AMOUNT REQUIRED FOR OXIDATIVE CONVERSION OF SAID FERROUS ION TO FERRIC ION AND (C) ACID IS ADDED TO SAID SEED PREPARATION SOLUTION AFTER FULL OXIDATIVE PREPARATION OF SAID SEED CRYSTALS, BUT BEFORE ADDITION OF SAID SEED CRYSTALS TO SAID CRYSTAL GROWTH SOLUTION, TO LOWER THE PH OF SAID SEED PREPARATION SOLUTION TO 2-5.

References Cited (Backward Citations)

No citation records indexed.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-10-28 1978-04-29 1978-10-29 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-10-28 1982-04-29 1982-10-29 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-10-28 1986-04-29 1986-10-29 $7700.00 Window Closed / Lapsed

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