US4019994A
Expired / Lapsed
US
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Process for the preparation of aqueous magnetic material suspensions
Assignee: Georgia-Pacific LLC
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Filing: 1975-08-28
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Granted: 1977-04-26
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Expires: 1995-08-28
Abstract
Abstract A process for the preparation of aqueous magnetic oxide suspensions is described.
Inventors
- 👤 Jack R. Kelley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:01
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/44; H01F1/445; G; G01; G01N; G01N27/00; G01N27/72; G01N27/82; G01N27/83; G01N27/84
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
98 words
A process for the preparation of magnetic fluid of a suspension of a ferromagnetic iron material in an aqueous medium which comprises mixing a petroleum sulfonate in the aqueous medium, dissolving an iron compound in the aqueous medium, adding an alkali to the aqueous medium, and reacting the mixture at a pH in the range of 5.5 to 8 to form magnetic iron oxide or magnetic hydroxyoxide, said iron being present in the aqueous medium as ferric and ferrous forms, and said petroleum sulfonate being mixed in an amount sufficient to disperse the iron oxide or iron hydroxide.
Claim 2
Dependent Claim
98 words
A process for the preparation of magnetic fluid of a suspension of a ferromagnetic iron material in an aqueous medium which comprises mixing a petroleum sulfonate in the aqueous medium, dissolving an iron compound in the aqueous medium, adding an alkali to the aqueous medium, and reacting the mixture at a pH in the range of 5.5 to 8 to form magnetic iron oxide or magnetic hydroxyoxide, said iron being present in the aqueous medium as ferric and ferrous forms, and said petroleum sulfonate being mixed in an amount sufficient to disperse the iron oxide or iron hydroxide.
Claim 3
Dependent Claim
22 words
A process according to claim 1 wherein the mixture is reacted at a temperature in the range of 40° to 250° C.
Claim 4
Dependent Claim
35 words
A process according to claim 2 wherein the iron compound is dissolved in the aqueous medium in an amount to form suspensions containing from 5 to 30 weight percent of magnetic iron oxide or hydroxyoxide.
Claim 5
Dependent Claim
44 words
A process according to claim 2 wherein the alkali is added to the aqueous medium containing the iron compound to maintain the reaction mixture at a pH in the range of 6 to 7 to convert the iron compound to the magnetic iron material.
Claim 6
Dependent Claim
26 words
A process according to claim 4 wherein the mixture is reacted until at least 0.8 equivalent of the alkali for an equivalent of iron has reacted.
Claim 7
Dependent Claim
28 words
A process according to claim 5 wherein the alkali is sodium hydroxide and the mixture is heated at a temperature in a range of 90° to 140° C.
Claim 8
Dependent Claim
21 words
A process according to claim 6 wherein the iron compound is a mixture of a ferric compound and a ferrous compound.
Claim 9
Dependent Claim
42 words
A process according to claim 6 wherein the iron compound is a ferrous salt and is dissolved in the aqueous medium in a sufficient amount to form a suspension containing from 5 to 30 weight percent of magnetic iron oxide or hydroxyoxide.
Claim 10
Dependent Claim
46 words
A process according to claim 8 wherein the ferrous salt is ferrous sulfate and the reaction mixture is heated to a temperature in the range of 85° to 100° C with agitation in air to oxidize a portion of the iron from ferrous to ferric state.
Claim 11
Dependent Claim
31 words
A process according to claim 9 wherein a compound of a metal selected from the group consisting of nickel and manganese is added with the iron compound to the aqueous medium.
Claim 12
Dependent Claim
20 words
A process according to claim 9 wherein the petroleum sulfonate dispersant is the water-soluble portion of the oil-soluble petroleum sulfonate.
Claim 13
Dependent Claim
10 words
A magnetic suspension prepared by the process of claim 1.
Claim 14
Dependent Claim
10 words
A magnetic suspension prepared by the process of claim 4.
Claim 15
Dependent Claim
10 words
a magnetic suspension prepared by the process of claim 6.
Claim 16
Dependent Claim
10 words
A magnetic suspension prepared by the process of claim 9.
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) | 1980-04-25 | 1980-10-25 | 1981-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-25 | 1984-10-25 | 1985-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-25 | 1988-10-25 | 1989-04-26 | $7700.00 | Window Closed / Lapsed |