US3987135A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of producing sintered magnesia
Assignee: Osterreichisch Amerikanische Magnesit AG
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Filing: 1972-04-19
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Granted: 1976-10-19
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Expires: 1992-04-19
Abstract
Abstract An improved process of forming sintered magnesia bodies from a magnesium hydroxide aqueous slurry wherein the slurry is dried to a moisture content where the solids can be compacted to self-supporting bodies, preferably about 5 to 8% moisture, by heating at a temperature below the dissociation temperature of the magnesium hydroxide, compacting the dried magnesium hydroxide into briquettes, heating the briquettes at a temperature above the dissociation temperature of magnesium hydroxide to form magnesia, re-compacting to form new briquettes of greater density, and heating to sintering temperature to sinter the briquettes.
Inventors
- 👤 Erich Eigner
- 👤 Robert Bergmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:55
CPC Classifications
C; C01; C01F; C01F5/00; C01F5/02; C01F5/06; C01F5/08; C01P; C01P2006/00; C01P2006/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
115 words
The method of producing sintered high density magnesia bodies from an aqueous magnesium hydroxide slurry, comprising the sequential steps of A. drying said slurry to a powder having a moisture content such that the magnesium hydroxide can be pressed to form self-supporting bodies, B. compacting said powder in molding means to form self-supporting briquettes, C. removing said briquettes from said molding means, D. heating said briquettes free from any mold under ambient pressure in said heating zone to a temperature above the dissociation temperature of magnesium hydroxide and below the sintering temperature of magnesia, E. recompacting said briquettes to a greater apparent specific gravity of about 2.0 g/cm 3 , and F. sintering said briquettes.
Claim 2
Independent Claim
115 words
The method of producing sintered high density magnesia bodies from an aqueous magnesium hydroxide slurry, comprising the sequential steps of A. drying said slurry to a powder having a moisture content such that the magnesium hydroxide can be pressed to form self-supporting bodies, B. compacting said powder in molding means to form self-supporting briquettes, C. removing said briquettes from said molding means, D. heating said briquettes free from any mold under ambient pressure in said heating zone to a temperature above the dissociation temperature of magnesium hydroxide and below the sintering temperature of magnesia, E. recompacting said briquettes to a greater apparent specific gravity of about 2.0 g/cm 3 , and F. sintering said briquettes.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein the moisture content of said powder is about 5 to 8 weight percent.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein said heating is at a temperature of from about 700° to 900° C.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein said heating is continued until the briquettes have essentially no ignition loss.
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) | 1979-10-19 | 1980-04-19 | 1980-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-19 | 1984-04-19 | 1984-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-19 | 1988-04-19 | 1988-10-19 | $7700.00 | Window Closed / Lapsed |