US3666653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryolitic linings in furnaces for aluminum smelting
Assignee: Montedison SpA
•
Filing: 1967-07-06
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Granted: 1972-05-30
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Expires: 1987-07-06
Abstract
Abstract Disclosed is an improvement in furnace vats for fused bath electrolysis of alumina which comprises a refractory mass of substantially pure natural or synthetic cryolite or of cryolitealumina mixtures in which a dispersion of carbon grit is within the refractory mass. Also disclosed is a process for preparing said mass.
Inventors
- 👤 Giuseppe De Varda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:07
CPC Classifications
C; C25; C25C; C25C3/00; C25C3/06; C25C3/08; C25C3/085; C04; C04B; C04B35/00; C04B35/515
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
18 words
The furnace vat of claim 1, wherein said vat is composed of at least one prefabricated shaped piece.
Claim 2
Dependent Claim
21 words
The furnace vat of claim 2, wherein the prefabricated shaped pieces consist of substantially pure cryolite containing carbon grit in dispersion.
Claim 3
Dependent Claim
20 words
The furnace vat of claim 2, wherein the prefabricated shaped pieces consist of cryolite-alumina mixtures, containing carbon grit in dispersion.
Claim 4
Dependent Claim
23 words
The furnace vat of claim 4, wherein the prefabricated shaped pieces consist of mixtures cryolite-alumina containing at least about 20 percent of Al2O3.
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) | 1975-05-30 | 1975-11-29 | 1976-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-30 | 1979-11-29 | 1980-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-30 | 1983-11-29 | 1984-05-30 | $7700.00 | Window Closed / Lapsed |