US3839167A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Novel alumina feed for aluminum cell
Assignee: Alcoa Corp
•
Filing: 1973-06-28
•
Granted: 1974-10-01
•
Expires: 1993-06-28
Abstract
Abstract Use of an alumina which has a total water of 3 to 20 wt.-percent and a surface area of at least 45 m2/g as cell feed improves the efficiency of operation of an electrolytic cell for reduction of alumina to aluminum.
Inventors
- 👤 W Sleppy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:57
CPC Classifications
C; C25; C25C; C25C3/00; C25C3/06; C25C3/18
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
75 words
A PROCESS FOR INCREASING THE EFFECIENCY OF SMELTING ALUMINUM, COMPRISING ADDING, SYBSTANTIALLY CONTINUOUSLY, DIRECTLY TO A MOLTEN ELECTROLYTE IN A CELL FOR THE ELECTROLYTIC REDUCTION OF ALUMINA TO ALUMINUM, AN ALUMINA WHICH HAS A TOTAL WATER OF FROM 3 TO 20 WEIGHT PERCENT AND A SURFACE AREA OF AT LEAST 45 M2/G, SAID ALUMINA COMPRISING UP TO 100 PERCENT OF THE AL2O3 FED TO SAID CELL, AND ELECTROLYTICALLY REDUCING ALUMINA TO ALUMINUM IN SAID CELL.
Claim 2
Dependent Claim
75 words
A PROCESS FOR INCREASING THE EFFECIENCY OF SMELTING ALUMINUM, COMPRISING ADDING, SYBSTANTIALLY CONTINUOUSLY, DIRECTLY TO A MOLTEN ELECTROLYTE IN A CELL FOR THE ELECTROLYTIC REDUCTION OF ALUMINA TO ALUMINUM, AN ALUMINA WHICH HAS A TOTAL WATER OF FROM 3 TO 20 WEIGHT PERCENT AND A SURFACE AREA OF AT LEAST 45 M2/G, SAID ALUMINA COMPRISING UP TO 100 PERCENT OF THE AL2O3 FED TO SAID CELL, AND ELECTROLYTICALLY REDUCING ALUMINA TO ALUMINUM IN SAID CELL.
Claim 3
Dependent Claim
30 words
The process of claim 1 wherein said alumina is added in increments at intervals of up to ten minutes in amounts calculated to maintain constant alumina concentration in the electrolyte.
Claim 4
Dependent Claim
39 words
The process of claim 1 wherein said electrolyte consists essentially of NaF, AlF3, and Al2O3 and has an NaF to AlF3 weight ratio up to 1.1:1 and wherein said alumina has a total water of 8 to 20 percent.
Claim 5
Dependent Claim
19 words
The process of claim 3 wherein said alumina has a total water in the range 10 to 18 percent.
Claim 6
Dependent Claim
19 words
The process of claim 3 wherein said alumina has a surface area in the range 135 to 180 m2/g.
Claim 7
Dependent Claim
26 words
The process of claim 1 wherein said alumina amounts to at least 50 percent by weight of the total amount of Al2O3 fed to the cell.
Claim 8
Dependent Claim
21 words
The process of claim 1 wherein said alumina amounts to at least 90 percent of the Al2O3 fed to the cell.
Claim 9
Dependent Claim
51 words
A process for increasing the efficiency of smelting aluminum, comprising adding, substantially continuously, directly to a molten electrolyte in a ceLl for the electrolytic reduction of alumina to aluminum, alumina having a water content effective for dispersing its individual particles upon addition thereof to said electrolyte but insufficient to cause mucking.
Claim 10
Dependent Claim
51 words
A process for increasing the efficiency of smelting aluminum, comprising adding, substantially continuously, directly to a molten electrolyte in a ceLl for the electrolytic reduction of alumina to aluminum, alumina having a water content effective for dispersing its individual particles upon addition thereof to said electrolyte but insufficient to cause mucking.
References Cited (Backward Citations)
US2464267A
Cited
US3135672A
Cited
US3128151A
Cited
US3294656A
Cited
US3582483A
Cited
US3729398A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |