Process for the heat treatment of spent pot linings derived from Hall-Heroult electrolytic cells
US5365012A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 1993 |
| Grant date | Nov 15, 1994 |
| Priority date | — |
| Expiry date | Jun 25, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S588/90
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A process for heat treating spent pot linings from Hall-Heroult electrolytic cells which comprise carbon and silico-aluminous materials impregnated with fluorides. The pot linings are ground to a particle size less than 5 mm, and formed into an intimate mixture with calcium sulfate or calcium sulfate dihydrate having a particle size less than 1 mm. The mixture is injected into the center of a vortex formed by a flow of circulating hot gas at the top part of a reactor at a temperature between 700.degree. and 1100.degree. C., and extracted from the bottom part of the reaction at a temperature between 400.degree. and 750.degree. C. after a contact time of less than 2 seconds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.