US3950504A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing magnesium aluminate spinel
Assignee: SPECIALTY REFRACTORIES Inc
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Filing: 1974-09-26
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Granted: 1976-04-13
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Expires: 1994-09-26
Abstract
Abstract Disclosed is the production of high purity magnesium aluminate spinel by blending alumina as ESP fines with a finely divided source of magnesia in a MgO:Al 2 O 3 weight ratio of between about 0.4 to 0.8 and firing the blend at 900°C. or above.
Inventors
- 👤 Jeffrey H. Belding
- 👤 Erwin A. Letzgus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:15
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/16; C01F7/162; C04; C04B; C04B35/00; C04B35/01; C04B35/44; C04B35/443
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
95 words
A process for the production of high purity magnesium aluminate spinel refractory which comprises blending alumina in the form of ESP fines with a finely divided source of magnesia in such proportion as to provide a magnesia:alumina weight ratio of about 0.4 to 0.8 and heating said blend to a temperature of from about 1600° to 2100°C for a period of time sufficient for substantially complete reaction of said blend to produce spinel having a bulk density of at least about 90 percent of theory and a sodium oxide content below about 0.1 weight percent.
Claim 2
Dependent Claim
95 words
A process for the production of high purity magnesium aluminate spinel refractory which comprises blending alumina in the form of ESP fines with a finely divided source of magnesia in such proportion as to provide a magnesia:alumina weight ratio of about 0.4 to 0.8 and heating said blend to a temperature of from about 1600° to 2100°C for a period of time sufficient for substantially complete reaction of said blend to produce spinel having a bulk density of at least about 90 percent of theory and a sodium oxide content below about 0.1 weight percent.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein said magnesia source is magnesium hydroxide.
Claim 4
Dependent Claim
16 words
The process of claim 1 wherein said blending is carried out in the presence of water.
Claim 5
Dependent Claim
18 words
The process of claim 1 wherein said alumina and said magnesia source are blended in approximately stoichiometric proportions.
Claim 6
Dependent Claim
10 words
The process of claim 1 wherein said blending includes grinding.
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) | 1979-04-13 | 1979-10-13 | 1980-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-13 | 1983-10-13 | 1984-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-13 | 1987-10-13 | 1988-04-13 | $7700.00 | Window Closed / Lapsed |