US4849382A
Expired / Lapsed
US
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Lightweight refractory and process for producing the same
Assignee: Nichias Corp
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Filing: 1988-02-18
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Granted: 1989-07-18
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Expires: 2008-02-18
Abstract
Abstract A lightweight refractory is disclosed which is a shaped porous body having refractory particles and aluminous short fibers bound to each other with mullite. The crtystalline structure of the refractory is chiefly composed of mullite and corundum. The mullite content is at least 12 mol % of the sum of mullite and corundum. The refractory is substantially free of free silica.
Inventors
- 👤 Kenichi Shibata
- 👤 Kouichi Kimura
- 👤 Tomohiko Hara
- 👤 Tatsuo Takagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:39
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/113; C04B35/101; C04B35/16; C04B35/18; C04B35/71; C04B35/78; C04B35/80; C04B38/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
67 words
A lightweight refractory which is a shaped porous body having refractory particles and aluminous short fibers bound to each other with mullite, the crystalline structure of said refractory being chiefly composed of mullite and corundum, the mullite content being at least 12 mol % of the sum of mullite and corundum, said refractory being substantially free of free silica and having a bulk specific gravity of 0.5-1.5.
Claim 2
Dependent Claim
67 words
A lightweight refractory which is a shaped porous body having refractory particles and aluminous short fibers bound to each other with mullite, the crystalline structure of said refractory being chiefly composed of mullite and corundum, the mullite content being at least 12 mol % of the sum of mullite and corundum, said refractory being substantially free of free silica and having a bulk specific gravity of 0.5-1.5.
Claim 3
Dependent Claim
22 words
A lightweight refractory according to claim 1 wherein said refractory particles are selected from the group consisting of alumina, mullite or alumina-mullite.
Claim 4
Dependent Claim
65 words
A process for producing a lightweight refractory comprising the steps of mixing 10-30 wt % of amorphous silica with polycrystalline aluminous short fibers cut to a length of 20-2,000 μm or a mixture thereof with no more than an equal amount of refractory particles, shaping the resulting mixture, and firing the shaped mixture at 1,400°-1,600° C. until it is found to contain no detectable cristobalite.
Claim 5
Dependent Claim
65 words
A process for producing a lightweight refractory comprising the steps of mixing 10-30 wt % of amorphous silica with polycrystalline aluminous short fibers cut to a length of 20-2,000 μm or a mixture thereof with no more than an equal amount of refractory particles, shaping the resulting mixture, and firing the shaped mixture at 1,400°-1,600° C. until it is found to contain no detectable cristobalite.
Claim 6
Dependent Claim
21 words
A process according to claim 3 wherein said refractory particles are selected from the group consisting of alumina, mullite or alumina-mullite.
Claim 7
Dependent Claim
88 words
A lightweight refractory which is a shaped porous body wherein refractory particles, aluminous short fibers cut to a length of no more than 2000 μm and aluminous continuous fibers cut to a length of 1-40 mm are bound to each other with mullite, the crystalline structure of said refractory being chiefly composed of mullite and corundum, the mullite content being at least 12 mol % of the sum of mullite and corundum, said refractory being substantially free of free silica and having a bulk specific gravity of 0.5-0.5.
Claim 8
Dependent Claim
88 words
A lightweight refractory which is a shaped porous body wherein refractory particles, aluminous short fibers cut to a length of no more than 2000 μm and aluminous continuous fibers cut to a length of 1-40 mm are bound to each other with mullite, the crystalline structure of said refractory being chiefly composed of mullite and corundum, the mullite content being at least 12 mol % of the sum of mullite and corundum, said refractory being substantially free of free silica and having a bulk specific gravity of 0.5-0.5.
Claim 9
Dependent Claim
77 words
A process for producing a lightweight refractory comprising the steps of mixing 10-30 wt % of amorphous silica with polycrystalline aluminous short fibers cut to a length of 20-2,000 μm and polycrystalline aluminuous continuous fibers cut to a length of 1-40 mm or a mixture thereof with no more than an equal amount of refractory particles, shaping the resulting mixture, and firing the shaped mixture at 1,400°-1,600° C. until it is found to contain no detectable cristobalite.
Claim 10
Dependent Claim
77 words
A process for producing a lightweight refractory comprising the steps of mixing 10-30 wt % of amorphous silica with polycrystalline aluminous short fibers cut to a length of 20-2,000 μm and polycrystalline aluminuous continuous fibers cut to a length of 1-40 mm or a mixture thereof with no more than an equal amount of refractory particles, shaping the resulting mixture, and firing the shaped mixture at 1,400°-1,600° C. until it is found to contain no detectable cristobalite.
Claim 11
Dependent Claim
17 words
A process according to claim 6 wherein said refractory particles are those of alumina, mullite or alumina-mullite.
Claim 12
Dependent Claim
33 words
A process according to claim 6 wherein the polycrystalline aluminous continuous fibers are used in amounts of 0.5-10 wt % of the sum of all the polycrystalline aluminous fibers and the refractory particles.
Claim 13
Dependent Claim
24 words
A process according to claim 6 wherein the polycrystalline aluminous continuous fibers have a length of 2-20 mm and a diameter of 5-20 μm.
Claim 14
Dependent Claim
17 words
A process according to claim 6 wherein the polycrystalline aluminous continuous fibers are cut from continuous filaments.
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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) | 1992-07-17 | 1993-01-16 | 1993-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-17 | 1997-01-16 | 1997-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-17 | 2001-01-16 | 2001-07-18 | $7700.00 | Window Closed / Lapsed |