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US4062920A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for producing lithium-containing ferrimagnetic materials

Assignee: Chevron USA Inc
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Filing: 1973-09-04
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Granted: 1977-12-13
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Expires: 1993-09-04
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Abstract

Abstract The invention is a process for manufacturing a material, a mass of finely divided particles of which an applied magnetic field can induce to change from a non-magnetized condition, in a sense of exhibiting no net external field, to a magnetized condition, in a sense of exhibiting an external field, which comprises: A. reacting starting materials comprising a salt of an alkali metal, e.g., lithium, sodium or potassium, a salt of a first metal in a divalent state, a salt of iron in a trivalent state, at least one of said salts being a halide, and an epoxy compound in the presence of a solvent selected from the group consisting of lower alkanols and water to obtain a mixture comprising a metal hydroxide-containing and solvent-containing gel; B. drying said gel to remove the majority of the solvent therefrom without significantly altering the distribution of lithium, sodium, or potassium therein to obtain porous particles; and C. heating the porous particles to produce the desired material. The preferred starting materials comprise a salt of lithium, a salt of manganese or magnesium, a salt of iron and propylene oxide, the preferred salts being the halides and, more particularly, the chlorides. The preferred solvent is methanol. Freeze drying is the preferred drying method.

Inventors

  • 👤 Robert H. Lindquist

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 02:12
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/0018; C01G49/0027; C01G49/009; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/2608; C04B35/2616; C01P; C01P2002/00; C01P2002/60; C01P2004/00; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/16

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 160 words
A process for manufacturing a material, a mass of finely divided particles of which an applied magnetic field can induce to change from a non-magnetized condition, in a sense of exhibiting no net external field, to a magnetized condition, in a sense of exhibiting an external field, which comprises: a. reacting starting materials comprising a salt of an alkali metal, a salt of a metal in a divalent state, a salt of iron in a trivalent state, at least one of said salts being a halide, and an epoxy compound, in the presence of a solvent selected from the group consisting of lower alkanols and water, to obtain a mixture comprising a metal hydroxide-containing and solvent-containing gel; b. freeze drying said gel to remove the majority of the solvent therefrom without significantly altering the distribution of alkali metal therein, to obtain porous particles; and c. heating the porous particles to a temperature above 600° C. to produce the desired material.
Claim 2
Dependent Claim 160 words
A process for manufacturing a material, a mass of finely divided particles of which an applied magnetic field can induce to change from a non-magnetized condition, in a sense of exhibiting no net external field, to a magnetized condition, in a sense of exhibiting an external field, which comprises: a. reacting starting materials comprising a salt of an alkali metal, a salt of a metal in a divalent state, a salt of iron in a trivalent state, at least one of said salts being a halide, and an epoxy compound, in the presence of a solvent selected from the group consisting of lower alkanols and water, to obtain a mixture comprising a metal hydroxide-containing and solvent-containing gel; b. freeze drying said gel to remove the majority of the solvent therefrom without significantly altering the distribution of alkali metal therein, to obtain porous particles; and c. heating the porous particles to a temperature above 600° C. to produce the desired material.
Claim 3
Dependent Claim 46 words
A process as in claim 1, including, as added steps after said freeze drying and before said heating: preheating the freeze-dried mixture at a temperature within the range from about 100° to about 500° C. for a time from about 2 hours to about 24 hours.
Claim 4
Dependent Claim 25 words
A process as in claim 2, wherein said porous particles are of a size within the range from about 20 microns to about 250 microns.
Claim 5
Dependent Claim 21 words
A process as in claim 1, including, as an added step before said heating: formulating said porous particles into toroidal shapes.
Claim 6
Dependent Claim 51 words
A process as in claim 4, wherein said formulating comprises: dispersing said porous particles in a polymerizable liquid; polymerizing said liquid in the form of a flat polymer sheet, said flat polymer sheet after said polymerizing having said porous particles dispersed therethroughout; and then stamping out shapes from said polymer sheet.
Claim 7
Dependent Claim 31 words
A process as in claim 1, wherein said salt of an alkali metal is a salt of lithium, said epoxy compound comprises propylene oxide and said solvent comprises methanol and water.
Claim 8
Dependent Claim 23 words
A process as in claim 1, wherein said metal in the divalent state is selected from the group consisting of manganese and magnesium.

References Cited (Backward Citations)

US3425666A Cited
US3370011A Cited
US3418161A Cited
US3607753A Cited
US3583918A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1980-12-12 1981-06-13 1981-12-13 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1984-12-12 1985-06-13 1985-12-13 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1988-12-12 1989-06-13 1989-12-13 $7700.00 Window Closed / Lapsed

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