US4025449A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process to produce barium and strontium ferrite
Assignee: Dow Chemical Co
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Filing: 1975-10-21
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Granted: 1977-05-24
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Expires: 1995-10-21
Abstract
Abstract A method to produce a magnetic barium or strontium ferrite comprising solubilizing an alkaline earth metal compound in an aqueous solution containing about 20 to about 60 weight percent alkali metal hydroxide. The resulting solution is heated to within the range of about 90° to about 130° C and thereafter admixed with a sufficient amount of a soluble iron compound to form a magnetic precipitate. A crystalline, magnetic ferrite is formed by heating the precipitate to within the range of about 800° to about 1500° C.
Inventors
- 👤 Paul A. Pezzoli
- 👤 Stanley F. Spangenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:16
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/0018; C01G49/0036; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/2683; C01P; C01P2002/00; C01P2002/02; C01P2002/30; C01P2002/34; C01P2002/70; C01P2002/76; C01P2004/00; C01P2004/60; C01P2004/62; C01P2006/00; C01P2006/42; C01P2006/60; C01P2006/80
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
103 words
A method of forming magnetic barium and strontium ferrites comprising (a) admixing an alkaline earth metal compound selected from compounds of barium and strontium with a sufficient amount of an aqueous solution containing from about 10 to about 60 weight percent alkali metal hydroxide to form a solution; (b) heating the solution of step (a) to within the range of from about 90° to about 130° C.; (c) admixing a sufficient amount of soluble iron compound with the heated solution to form a magnetic spinel precipitate which is at least partially amorphous; and (d) removing the precipitate from the mixture of step (c).
Claim 2
Independent Claim
103 words
A method of forming magnetic barium and strontium ferrites comprising (a) admixing an alkaline earth metal compound selected from compounds of barium and strontium with a sufficient amount of an aqueous solution containing from about 10 to about 60 weight percent alkali metal hydroxide to form a solution; (b) heating the solution of step (a) to within the range of from about 90° to about 130° C.; (c) admixing a sufficient amount of soluble iron compound with the heated solution to form a magnetic spinel precipitate which is at least partially amorphous; and (d) removing the precipitate from the mixture of step (c).
Claim 3
Dependent Claim
85 words
The method of claim 1 wherein the alkaline earth metal compound is at least one member of the group consisting of Ba(C 2 H 3 O 2 ) 2 , Sr(C 2 H 3 O 2 ) 2 , Ba(NO 3 ) 2 , Sr(NO 3 ) 2 , BaF 2 , SrF 2 , BaCl 2 , SrCl 2 , BaBr 2 , SrBr 2 , BaI 2 , SrI 2 , Ba(OH) 2 , Sr(OH) 2 , BaCO 3 and SrCO 3 .
Claim 4
Dependent Claim
53 words
The method of claim 1 wherein the alkaline earth metal compound is at least one member of the group consisting of Ba(C 2 H 3 O 2 ) 2 , Ba(NO 3 ) 2 , BaF 2 , BaCl 2 , BaBr 2 , BaI 2 , Ba(OH) 2 and BaCO 3 .
Claim 5
Dependent Claim
15 words
The method of claim 1 wherein the alkaline earth metal compound is a barium chloride.
Claim 6
Dependent Claim
25 words
The method of claim 1 wherein the alkali metal hydroxide is at least one member of the group consisting of NaOH, KOH, RbOH and CsOH.
Claim 7
Dependent Claim
12 words
The method of claim 1 wherein the alkali hydroxide is sodium hydroxide.
Claim 8
Dependent Claim
57 words
The method of claim 1 wherein the iron compound is at least one member of the group consisting of FeCl 3 , FeBr 3 , Fe(NO 3 ) 3 , Fe 2 (SO 4 ) 3 , Fe(C 2 H 3 O 2 ) 2 , Fe 2 (C 2 O 4 ) 3 and hydrates thereof.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein the iron compound is an iron chloride.
Claim 10
Dependent Claim
28 words
The method of claim 1 wherein the alkaline earth compound is a barium chloride, the alkali hydroxide is sodium hydroxide and the iron compound is a ferric chloride.
Claim 11
Dependent Claim
24 words
The method of claim 1 including drying the precipitate of step (d) within the temperature range of from about 20° to about 200° C.
Claim 12
Dependent Claim
28 words
The method of claim 1 wherein the molar ratio of the alkali hydroxide to the iron compound is within the range of from about 0.1:1 to about 5:1.
Claim 13
Dependent Claim
25 words
The method of claim 1 wherein the heating in step (b) is carried out within the range of from about 110° to about 115° C.
Claim 14
Dependent Claim
15 words
The method of claim 1 wherein the precipitate removed in step (d) is predominantly amorphous.
Claim 15
Dependent Claim
28 words
The method of claim 1 wherein the precipitate of step (d) is a magnetic spinel consisting essentially of barium oxide, iron oxide and a minor amount of impurities.
Claim 16
Independent Claim
120 words
A method of forming a magnetic barium-ferrite comprising sequentially (a) admixing barium chloride with a sufficient amount of an aqueous solution containing about 10 to about 60 weight percent sodium hydroxide to produce a solution; (b) heating the barium chloride-sodium hydroxide solution to a temperature within the range of from about 90° to about 130° C.; (c) admixing a sufficient amount of an aqueous ferric chloride solution with the barium chloride-sodium hydroxide solution of step (b) to provide a sodium hydroxide to ferric chloride molar ratio of from about 0.1:1 to about 5:1, and (d) removing a magnetic precipitate from the mixture of step (c); the magnetic precipitate being predominantly amorphous with a minor portion having a spinel crystalline symmetry.
Claim 17
Independent Claim
120 words
A method of forming a magnetic barium-ferrite comprising sequentially (a) admixing barium chloride with a sufficient amount of an aqueous solution containing about 10 to about 60 weight percent sodium hydroxide to produce a solution; (b) heating the barium chloride-sodium hydroxide solution to a temperature within the range of from about 90° to about 130° C.; (c) admixing a sufficient amount of an aqueous ferric chloride solution with the barium chloride-sodium hydroxide solution of step (b) to provide a sodium hydroxide to ferric chloride molar ratio of from about 0.1:1 to about 5:1, and (d) removing a magnetic precipitate from the mixture of step (c); the magnetic precipitate being predominantly amorphous with a minor portion having a spinel crystalline symmetry.
Claim 18
Dependent Claim
12 words
The method of claim 15 including drying the precipitate of step (d).
Claim 19
Dependent Claim
25 words
The method of claim 15 wherein the heating in step (b) is carried out within the range of from about 110° to about 115° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-23 | 1980-11-22 | 1981-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-23 | 1984-11-22 | 1985-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-23 | 1988-11-22 | 1989-05-24 | $7700.00 | Window Closed / Lapsed |