Patent US4286990A successfully refreshed from Google Patents.
US4286990A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature stabilized, pyrogenically produced aluminum oxide-mixed oxide, the process for its production and use
Assignee: Evonik Operations GmbH
•
Filing: 1980-07-31
•
Granted: 1981-09-01
•
Expires: 2000-07-31
Abstract
Abstract There is provided temperature stabilized pyrogenically produced aluminum oxide-mixed oxide having a BET surface area of 50 to 200 m 2 /g which contains 0.5 to 20 weight % silicon dioxide as a constituent thereof. Because of the silicon dioxide constituent the aluminum oxide does not change into the α-Al 2 O 3 phase until 1350° C. The temperature stabilized aluminum oxide-mixed oxide is suitable for the production of thermal insulation compositions.
Inventors
- 👤 Peter Kleinschmit
- 👤 Rudolf Schwarz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:37
CPC Classifications
C; C01; C01B; C01B13/00; C01B13/14; C01B13/20; C01B13/22; C01F; C01F7/00; C01F7/02; C01F7/30; C01F7/302; C04; C04B; C04B14/00; C04B14/02; C04B14/30; C04B30/00; C04B35/00; C04B35/01; C04B35/10; C01P; C01P2004/00; C01P2004/01; C01P2004/03; C01P2004/50; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/12
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
45 words
Temperature stabilized, pyrogenically produced aluminum oxide-silicon dioxide mixed oxide having a BET surface area of 50 to 200 m 2 /g, the silicon dioxide being 0.5 to 20 weight % of the mixed oxide, the balance of the mixed oxide consisting essentially of aluminum oxide.
Claim 2
Dependent Claim
45 words
Temperature stabilized, pyrogenically produced aluminum oxide-silicon dioxide mixed oxide having a BET surface area of 50 to 200 m 2 /g, the silicon dioxide being 0.5 to 20 weight % of the mixed oxide, the balance of the mixed oxide consisting essentially of aluminum oxide.
Claim 3
Dependent Claim
31 words
A mixed oxide according claim 1 wherein the aluminum oxide is in the δ-form and is stabilized against transformation to the α-form up to a temperature of at least 1300° C.
Claim 4
Dependent Claim
16 words
A mixed oxide according to claim 2 containing 0.6 to 14.5 weight % of silicon dioxide.
Claim 5
Dependent Claim
14 words
A mixed oxide according to claim 3 containing about 2.5 weight % silicon dioxide.
Claim 6
Dependent Claim
27 words
A mixed oxide according to claim 4 having a specific surface area of about 150 m 2 /g and an average particle diameter of about 7 nm.
Claim 7
Dependent Claim
46 words
A mixed oxide according to claim 5 having a thermal conductivity of about 1.6×10 -2 W/m×°K. and which is capable on heating to 1300° C. for 5 hours of maintaining its thermal conductivity at not over about 2.6×10 -2 W/m×°K. at a load of 15 g/cm.
Claim 8
Dependent Claim
73 words
A process of preparing the product of claim 2 comprising vaporizing aluminum trichloride, supplying it with air to the mixing chamber of a burner, also supplying to the mixing chamber hydrogen and silicon tetrachloride in a ratio to give the aluminum oxide-silicon dioxide mixed oxide containing 0.5 to 20 weight % silicon dioxide, burning the 4-component mixture in a reaction chamber and separating the solid aluminum oxide-silicon dioxide from the gaseous reaction products.
Claim 9
Dependent Claim
26 words
A process according to claim 7 including the step of heating the solid aluminum oxide-silicon dioxide mixed oxide in moist air to remove adhering hydrogen chloride.
Claim 10
Dependent Claim
61 words
A process according to claim 7 wherein the ratio of aluminum chloride to air is 0.25 to 0.72 kg of aluminum chloride to 1 Nm 3 of air and the ratio of hydrogen to the total of aluminum chloride and silicon tetrachloride is 0.8 to 1.5 Nm 3 of hydrogen to 2.7 to 3.2 kg of aluminum chloride and silicon tetrachloride.
Claim 11
Dependent Claim
61 words
A process according to claim 7 wherein the ratio of aluminum chloride to air is 0.45 to 0.52 kg of aluminum chloride to 0.9 to 1.1 Nm 3 and the ratio of hydrogen to the total of aluminum chloride and silicon tetrachloride is 0.9 to 1.1 Nm 3 of hydrogen to 2.8 to 3.0 kg of aluminum chloride and silicon tetrachloride.
Claim 12
Dependent Claim
26 words
A process according to claim 10 wherein the solid aluminum oxide-silicon dioxide is separated from the gaseous reaction products in a cyclone or by a filter.
Claim 13
Dependent Claim
13 words
A process according to claim 11 wherein the separation is in a cyclone.
Claim 14
Dependent Claim
13 words
A process according to claim 11 wherein the separation is by a filter.
Claim 15
Dependent Claim
26 words
A process according to claim 9 wherein the solid aluminum oxide-silicon dioxide is separated from the gaseous reaction products in a cyclone or by a filter.
Claim 16
Dependent Claim
14 words
A mixed oxide according to claim 1 consisting of aluminum oxide and silicon dioxide.
Claim 17
Dependent Claim
12 words
A mixed oxide according to claim 1 in the form of particles.
References Cited (Backward Citations)
US3784388A
Cited
US3865599A
Cited
US4094690A
Cited
US3989783A
Cited
US4040998A
Cited
US4028453A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-31 | 1985-03-02 | 1985-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-31 | 1989-03-02 | 1989-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-31 | 1993-03-02 | 1993-09-01 | $7700.00 | Window Closed / Lapsed |