Plasma torch furnace processing of spent potliner from aluminum smelters
US5222448A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 1992 |
| Grant date | Jun 29, 1993 |
| Priority date | — |
| Expiry date | Apr 13, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/91
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Spent potliner from aluminum reduction cells includes carbon, inorganic brick and refractory material, and fluoride, sulfur, and cyanide compounds, and is considered hazardous. It is treated by introducing it into a vessel, and exposing it to the heat of a plasma torch at a temperature of at least 1000.degree. C. As a result, carbon is gasified and converted to combustible carbon monoxide or hydrocarbons, or to carbon dioxide; inorganic material is melted form slag; fluoride compounds are melted, vaporized, or reduced to gaseous HF; cyanide compounds are destroyed; and all other materials, including sulfur compounds, are either melted or gasified. As a result, the spent potliner is rendered non-hazardous, and the quantity of remaining slag has both its solid volume and mass substantially reduced by a factor of at least 1.5:1 in mass and at least 3:1 in volume relative to the input spent potliner. The process allows gaseous fluoride compounds to be captured and thermal energy produced in the process to be extracted. The molten slag material produced within the vessel is removed from the vessel, and cooled to form a solid slag which is substantially free of cyanide compounds, resisti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.