Process for the production of alumina
US4526763A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 3, 1982 |
| Grant date | Jul 2, 1985 |
| Priority date | — |
| Expiry date | May 3, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01F7/26
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
In a process for the production of alumina from aluminous raw material, an ammonoalunite intermediate is formed. The raw material is preferably a clay which is leached with sulfuric acid to form an aluminous solution which is separated from the solid materials. After any required extraction of iron, such as by liquid ion exchange, the solution is subjected to elevated temperatures and pressures in the presence of ammonium ions to form ammonoalunite which is recovered as a precipitate. The liquor is recycled to leach the clay, while the ammonoalunite is thermally decomposed to alumina. Gases liberated during decomposition are scrubbed with recycled liquor to form clay leach liquor. The alumina may be purified by washing with sulfuric acid to obtain a purity suitable for aluminum electrolysis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.