US3725222A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of aluminum
Assignee: Alcoa Corp
•
Filing: 1971-10-26
•
Granted: 1973-04-03
•
Expires: 1991-10-26
Abstract
Abstract Production of aluminum by continuous electrolysis of aluminum chloride in molten electrolyte of controlled oxide content.
Inventors
- 👤 A Russell
- 👤 L Knapp
- 👤 W Haupin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:23
CPC Classifications
C; C25; C25C; C25C3/00; C25C3/06; C25C3/18
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
22 words
A process in accordance with claim 1 wherein the percent by weight of oxide in the bath does not exceed 0.1 percent.
Claim 2
Dependent Claim
22 words
A process in accordance with claim 1 wherein the percent by weight of oxide in the bath does not exceed 0.05 percent.
Claim 3
Dependent Claim
27 words
A process in accordance with claim 1 wherein the said aluminum chloride fed into the electrolytic bath contains less than 0.25 percent by weight of metal oxide.
Claim 4
Dependent Claim
27 words
A process in accordance with claim 4 wherein the said aluminum chloride fed into the electrolytic bath contains less than 0.1 percent by weight of metal oxide.
Claim 5
Dependent Claim
27 words
A process in accordance with claim 4 wherein the said aluminum chloride fed into the electrolytic bath contains less than 0.05 percent by weight of metal oxide.
Claim 6
Dependent Claim
24 words
A process in accordance with claim 1 wherein the concentration of aluminum chloride in the said bath is maintained at 1-15 percent by weight.
Claim 7
Dependent Claim
26 words
A process in accordance with claim 7 wherein the aluminum chloride fed into the electrolytic bath contains less than 0.25 percent by weight of metal oxide.
Claim 8
Dependent Claim
56 words
A process in accordance with claim 1 wherein upon increase in the concentration of metal oxide in the bath above a predetermined desired level through introduction of undissolved metal oxide into the bath, sufficient metal oxide is removed from the bath to reduce the concentration of metal oxide in the bath below the said predetermined level.
Claim 9
Dependent Claim
63 words
A process in accordance with claim 9 wherein the removal of metal oxide from the bath is effected by increasing the capacity of the bath thru effected by increasing the capacity of the to dissolve metal oxide and thereafter electrolyzing sufficient dissolved metal oxide from the bath that the concentration of metal oxide in the bath returns to the said predetermined desired level.
Claim 10
Dependent Claim
33 words
A process in accordance with claim 10 wherein the said increasing of the capacity of the bath to dissolve metal oxide is effected by increasing the concentration of aluminum chloride in the bath.
Claim 11
Dependent Claim
30 words
A process in accordance with claim 10 wherein the said increasing of the capacity of the bath to dissolve metal oxide is effected by decreasing the temperature of the bath.
Claim 12
Dependent Claim
40 words
A process in accordance with claim 10 wherein the said solvent consists essentially of alkali metal chloride, and the said increasing of the capacity of the bath to dissolve metal oxide is effected by adding a fluoride to the bath.
Claim 13
Dependent Claim
38 words
A process in accordance with claim 9 wherein the said removal of metal oxide from the bath is effected by temporarily decreasing the current density sufficiently to increase the rate of electrolysis of metal oxide from the solution.
Claim 14
Dependent Claim
24 words
A process in accordance with claim 9 wherein the said removal of metal oxide is effected by filtration of undissolved oxides from the bath.
Claim 15
Dependent Claim
32 words
A process in accordance with claim 1 wherein the said solvent consists essentially of at least one salt selected from the group consisting of alkali metal halides and alkaline earth metal halides.
Claim 16
Dependent Claim
32 words
A process in accordance with claim 1 wherein the said solvent consists essentially of at least one salt selected from the group consisting of alkali metal chlorides and alkaline earth metal chlorides.
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) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |