US3689615A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of improving refractory bricks
Assignee: Borsodnadasdi Lemezgyar
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Filing: 1971-01-04
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Granted: 1972-09-05
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Expires: 1991-01-04
Abstract
Abstract Heat and wear resistance and other properties of refractory bricks are improved by embedding them in a special powder and heating them in an oxygen-free atmosphere at 900*-1,100* C. for 18-36 hours. The powder is prepared by heating bauxite powder slowly to 950*-1,100* C. and keeping it there for 10-15 hours, then cooling and comminuting the powder and admixing 40-60 percent by weight of it with 40-60 percent by weight of powdered aluminum and 1-6 percent by weight of powdered ammonium chloride, then annealing this intermediate powder at 950*-1,100* C. for 2226 hours, cooling and comminuting and admixing 10-20 percent by weight powdered aluminum and 0.5-3 percent by weight powdered aluminum chloride.
Inventors
- 👤 Miklos Sandor
- 👤 Istvan Nyitray
- 👤 Jozsef Nemeth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:28
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/01; C04B35/10
Claims Analysis
Total Claims: 0
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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) | 1975-09-05 | 1976-03-06 | 1976-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-05 | 1980-03-06 | 1980-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-05 | 1984-03-06 | 1984-09-05 | $7700.00 | Window Closed / Lapsed |