US4469669A
Expired / Lapsed
US
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Preparation of ferrites from iron (II) sulfate
Assignee: BASF SE
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Filing: 1983-04-14
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Granted: 1984-09-04
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Expires: 2003-04-14
Abstract
Abstract M-Type ferrites of the formula AFe 12 O 19 , Me 2 Y-type ferrites of the formula A 2 Me 2 Fe 12 O 22 or spinel-type ferrites of the formula MeFe 2 O 4 , where A is Ba, Sr, Pb and/or Ca and Me is Zn, Mn, Co, Cu, Fe(II) and/or 1/2(Li(I)+Fe(III)), are prepared by a process wherein iron(II) sulfate hydrate is dehydrated and oxidized and then mixed with sodium carbonate and/or potassium carbonate and salts and/or oxides of other A and/or Me cations required in addition to Fe(III) for ferrite formation, the mixture is heated at from 700° to 1,200° C., and the resulting ferrite is isolated by leaching with water.
Inventors
- 👤 Hartmut Hibst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:29
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/0018; C01G49/0036; C01G49/0063; C01G49/0072; C01G49/009; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/2608; C04B35/2633; C04B35/2683; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/10; H01F1/11; C01P; C01P2002/00; C01P2002/30; C01P2002/32; C01P2004/00; C01P2004/60; C01P2004/62; C01P2006/00; C01P2006/12; C01P2006/42; C01P2006/60; C01P2006/80
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
150 words
A process for the preparation of an M-type ferrite of the formula AFe 12 O 19 , an Me 2 Y-type ferrite of the formula A 2 Me 2 Fe 12 O 22 or a spinel-type ferrite of the formula MeFe 2 O 4 , where A is Ba, Sr, Pb and/or Ca and Me is Zn, Mn, Co, Cu, Fe(II) and/or 1/2(Li(I)+Fe(III)), wherein iron(I) sulfate hydrate is dehydrated under a pressure of less than 0.8 bar at from 50° to 350° C. and then heated in an oxidizing gas stream at from 50° to 600° C., the resulting product is mixed with sodium carbonate and/or potassium carbonate and salts and/or oxides of other A and/or Me cations required in addition to Fe(III) for the particular ferrite composition, the mixture obtained is heated at from 700° to 1,200° C., and the resulting ferrite is then isolated by leaching with water.
Claim 2
Dependent Claim
150 words
A process for the preparation of an M-type ferrite of the formula AFe 12 O 19 , an Me 2 Y-type ferrite of the formula A 2 Me 2 Fe 12 O 22 or a spinel-type ferrite of the formula MeFe 2 O 4 , where A is Ba, Sr, Pb and/or Ca and Me is Zn, Mn, Co, Cu, Fe(II) and/or 1/2(Li(I)+Fe(III)), wherein iron(I) sulfate hydrate is dehydrated under a pressure of less than 0.8 bar at from 50° to 350° C. and then heated in an oxidizing gas stream at from 50° to 600° C., the resulting product is mixed with sodium carbonate and/or potassium carbonate and salts and/or oxides of other A and/or Me cations required in addition to Fe(III) for the particular ferrite composition, the mixture obtained is heated at from 700° to 1,200° C., and the resulting ferrite is then isolated by leaching with water.
Claim 3
Dependent Claim
34 words
A process as claimed in claim 1, wherein the iron(II) sulfate hydrate is dehydrated until more than 50% of the water of hydration has been removed, the temperature being progressively increased during this procedure.
Claim 4
Dependent Claim
42 words
A process as claimed in claim 1, wherein the dehydrated iron(II) sulfate hydrate is oxidized in a stream of air until more than 80% of the divalent iron has been converted into trivalent iron, the temperature being progressively increased during this procedure.
Claim 5
Dependent Claim
34 words
A process as claimed in claim 1, wherein the A and/or Me cations, which are required in addition to the Fe(III) cation for the composition of the particular ferrite, are sulfates, chlorides or carbonates.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1987-09-04 | 1988-03-05 | 1988-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-04 | 1992-03-05 | 1992-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-04 | 1996-03-05 | 1996-09-04 | $7700.00 | Window Closed / Lapsed |