US4311684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing iron oxide containing magnetite
Assignee: TDK Corp
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Filing: 1980-04-24
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Granted: 1982-01-19
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Expires: 2000-04-24
Abstract
Abstract In a process for producing an iron oxide having magnetite as a main component by heating to reduce a powder of an iron oxide or a hydrated iron oxide in an atmosphere for reduction, an improvement characterized in that said atmosphere for reduction comprises an inert gas, steam and a gas of an organic compound for reducing an iron oxide.
Inventors
- 👤 Shinji Umeki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:32
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70652; B; B82; B82Y; B82Y30/00; C; C01; C01G; C01G49/00; C01G49/02; C01G49/08; C01P; C01P2004/00; C01P2004/10; C01P2004/54; C01P2004/60; C01P2004/62; C01P2004/64; C01P2006/00; C01P2006/12; C01P2006/42
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
131 words
In a process for producing an iron oxide comprising magnetite as the main component by heating a powder of goethite, lepidocrosite, α-iron oxide or γ-iron oxide in a reducing atmosphere, the improvement comprising using as the reducing atmosphere an inert gas containing steam and a gas of an organic compound for reducing an iron oxide selected from the group consisting of lower alcohols, ketones, ethers, esters and hydrocarbons; wherein the ratio of steam to the gas of an organic compound is in the range of 2-500% by volume; and wherein the heating is carried out at 500° to 700° C.; the iron oxide comprising magnetite being unsintered and chemically stable and exhibiting a higher H c than the iron oxide comprising magnetite prepared as above but heated at a lower temperature.
Claim 2
Dependent Claim
131 words
In a process for producing an iron oxide comprising magnetite as the main component by heating a powder of goethite, lepidocrosite, α-iron oxide or γ-iron oxide in a reducing atmosphere, the improvement comprising using as the reducing atmosphere an inert gas containing steam and a gas of an organic compound for reducing an iron oxide selected from the group consisting of lower alcohols, ketones, ethers, esters and hydrocarbons; wherein the ratio of steam to the gas of an organic compound is in the range of 2-500% by volume; and wherein the heating is carried out at 500° to 700° C.; the iron oxide comprising magnetite being unsintered and chemically stable and exhibiting a higher H c than the iron oxide comprising magnetite prepared as above but heated at a lower temperature.
Claim 3
Dependent Claim
30 words
The process according to claim 1, wherein the improvement further comprises forming said reducing atmosphere by bubbling the inert gas through an aqueous mixture of water and the organic compound.
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) | 1985-01-18 | 1985-07-20 | 1986-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-18 | 1989-07-20 | 1990-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-18 | 1993-07-20 | 1994-01-19 | $7700.00 | Window Closed / Lapsed |