Process for regulating the acidity of all-Heelectrolytic cells
US4867851A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 14, 1988 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Sep 14, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25C3/22
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The invention relates to a process for regulating the acidity of the electrolytic bath by recycling fluorinated effluents emitted by the Hall-Heroult electrolytic cells for the production of aluminum, in which said fluorinated effluents are collected, by the dry route, on the alumina. It comprises the following stages: PA0 a reference value for the fluorine/alumina weight ratio is fixed in connection with the alumina leaving the collecting apparatus, PA0 a continuous measurement takes place of the fluorine and alumina quantities entering the collecting apparatus, PA0 the alumina flow rate is regulated so as to maintain the F/Al.sub.2 O.sub.3 ratio at its reference value, generally fixed between 0.5 and 3%, PA0 fluorinated alumina is fed into a storage means with a predetermined capacity and equipped with a level measuring means, PA0 the electrolytic cells are supplied with the fluorinated alumina taken from the storage means and PA0 the acidity of each cell is adjusted through the addition of aluminum fluoride and/or varying the power dissipated in the cell.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.