US3615306A
Expired / Lapsed
US
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A method for producing alpha-alumina crystals from aluminum oxide
Assignee: Saint Gobain Abrasives Inc
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Filing: 1967-10-12
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Granted: 1971-10-26
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Expires: 1987-10-12
Abstract
Abstract Abrasive sized crystalline alpha alumina crystals are produced from A1203 containing powder by heating alumina source with source of soda and Titania to 1475* to 1700* C., with crystallization taking place above 1475* C. in presence of atmosphere which is reducing with respect to soda.
Inventors
- 👤 Cecil M Jones
- 👤 John J Amero
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:40
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/021; C09; C09K; C09K3/00; C09K3/14; C09K3/1409; C01P; C01P2004/00; C01P2004/20; C01P2004/54; C01P2004/60; C01P2004/61; C01P2004/62; C01P2006/00; C01P2006/11; C01P2006/14; C01P2006/21
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
17 words
heating said composition within a temperature range from about 1,450* C. to the melting temperature of alpha-alumina;
Claim 2
Dependent Claim
19 words
A process as defined in claim 1 in which the reaction mix is pressed into pellets prior to heating.
Claim 3
Dependent Claim
22 words
A process as defined in claim 1 in which said alumina containing material has a particle size of 20 microns or less.
Claim 4
Dependent Claim
38 words
holding said composition at a temperature within said temperature range for from 1 to 6 hours under conditions whereby more than 95% of the soda content is removed from the reaction mix in from 1 to 6 hours;
Claim 5
Dependent Claim
11 words
cooling the reaction mix and separating abrasive sized alpha-alumina crystals therefrom.
Claim 6
Dependent Claim
38 words
A process as defined in claim 1 in which the reaction mix is subjected to an atmosphere which reacts with sodium oxide to produce a reaction product, including sodium, which has a vapor pressure higher than sodium oxide.
Claim 7
Dependent Claim
25 words
A process as defined in claim 1 in which the reaction mix is subjected to an atmosphere which is reducing with respect to sodium oxide.
Claim 8
Dependent Claim
21 words
A process as defined in claim 1 in which the reaction mix is exposed to an atmosphere which includes carbon monoxide.
Claim 9
Dependent Claim
20 words
A process as defined in claim 1 in which the reaction mix is exposed to an atmosphere which includes hydrogen.
Claim 10
Dependent Claim
19 words
A process as defined in claim 1 in which methane is injected into the atmosphere surrounding the reaction mix.
Claim 11
Dependent Claim
27 words
A process as in claim 1 in which the said soda containing or generating material is selected from the group consisting of sodium carbonate and sodium sulfate.
Claim 12
Dependent Claim
16 words
A process as in claim 1 in which the said alumina containing material consists of beta-alumina.
Claim 13
Dependent Claim
16 words
A process as in claim 1 in which said Titania containing material consisting of titanium dioxide.
References Cited (Backward Citations)
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US2725286A
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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) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |