US4339425A
Expired / Lapsed
US
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Process for producing acicular hydrated ferric oxide particles
Assignee: TDK Corp
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Filing: 1980-11-25
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Granted: 1982-07-13
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Expires: 2000-11-25
Abstract
Abstract Acicular hydrated ferric oxide particles are produced by premixing an aged ferric hydroxide with a newly formed ferric hydroxide or a mixture of ferrous hydroxide and an oxidizing agent and treating the pre-mixture by a hydrothermal reaction of said pre-mixture at 100° to 250° C.
Inventors
- 👤 Yasumichi Tokuoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:36
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; C; C01; C01G; C01G49/00; C01G49/02; C01G49/06; C01P; C01P2004/00; C01P2004/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
104 words
A process for producing acicular hydrated ferric oxide particles comprising mainly goethite without branch shapes which comprises premixing aged ferric hydroxide which has been aged by treating an aqueous ferric hydroxide slurry at a temperature between room temperature and 70° C. for 3 to 30 hours, with a newly formed ferric hydroxide or a mixture of ferrous hydroxide and an oxidizing agent, said aged ferric hydroxide being at a molar ratio of from 1:4 to 1:2 to the newly formed ferric hydroxide or ferrous hydroxide, and hydrothermally treating the premixture as a slurry in an autoclave at 100°-250° C. for 1 to 20 hours.
Claim 2
Dependent Claim
104 words
A process for producing acicular hydrated ferric oxide particles comprising mainly goethite without branch shapes which comprises premixing aged ferric hydroxide which has been aged by treating an aqueous ferric hydroxide slurry at a temperature between room temperature and 70° C. for 3 to 30 hours, with a newly formed ferric hydroxide or a mixture of ferrous hydroxide and an oxidizing agent, said aged ferric hydroxide being at a molar ratio of from 1:4 to 1:2 to the newly formed ferric hydroxide or ferrous hydroxide, and hydrothermally treating the premixture as a slurry in an autoclave at 100°-250° C. for 1 to 20 hours.
References Cited (Backward Citations)
US3075919A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-12 | 1986-01-11 | 1986-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-12 | 1990-01-11 | 1990-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-12 | 1994-01-11 | 1994-07-13 | $7700.00 | Window Closed / Lapsed |