Direct fuel-fired furnace arrangement for the recovery of gallium and germanium from coal fly ash
US4643110A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1986 |
| Grant date | Feb 17, 1987 |
| Priority date | — |
| Expiry date | Jul 7, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S588/90
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A furnace arrangement utilizes a single vertically disposed shaft furnace incorporating the features of pellet drying and hardening, oxidizing heat-up, reducing roast and gas separation. The upper portion of the furnace dries and hardens "green" pellets while at the same time subjecting them to an oxidizing atmosphere and temperature increase. A stack of the pellets slowly moves downwardly through a transistion zone to a reducing atmosphere in a lower portion of the furnace. A heated reducing gas circulates through this lower portion and out of the furnace through a recovery system of the furnace arrangement. After the sublimate carried by the reducing gas is removed, the reducing gas is supplemented and returned to the lower portion of the furnace to again produce a reducing atmosphere. A smaller branch of cooled reducing gas enters the lower portion of the furnace adjacent the bottom to cool the pellet residue immediately prior to removal from the furnace.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.