Bath for electrolytic reduction of alumina and method therefor
US6485628B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 2000 |
| Grant date | Nov 26, 2002 |
| Priority date | — |
| Expiry date | Nov 25, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25C3/18
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An electrolytic bath for use during the electrolytic reduction of alumina to aluminum. The bath comprises a molten electrolyte having the following ingredients: (a) AlF3 and at least one salt selected from the group consisting of NaF, KF, and LiF; and (b) about 0.004 wt. % to about 0.2 wt. %, based on total weight of the molten electrolyte, of at least one transition metal or at least one compound of the metal or both. The compound may be, for example, a fluoride, oxide, or carbonate. The metal can be nickel, iron, copper, cobalt, or molybdenum. The bath can be employed in a combination that includes a vessel for containing the bath and at least one non-consumable anode and at least one dimensionally stable cathode in the bath. Employing the bath of the present invention during electrolytic reduction of alumina to aluminum can improve the wetting of aluminum on a cathode by reducing or eliminating the formation of non-metallic deposits on the cathode. Removing sulfur from the bath can also minimize cathode deposits. Aluminum formed on the cathode can be removed directly from the cathode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.