Continuous process for obtaining pure alumina from an acidic liquor originating from the chlorosulphuric attack of an aluminous ore and for the purification of the liquor which has been freed from alumina
US4241030A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1979 |
| Grant date | Dec 23, 1980 |
| Priority date | — |
| Expiry date | May 8, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01F7/26
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for obtaining pure alumina comprising the combination of chlorosulphuric attack of calcined aluminous ores containing impurities, followed by concentration of the liquor obtained after the attack and separation of the sterile material, sulphuric acid treatment of the concentrated liquor followed by chlorination to precipitate almost all the hexahydrated aluminum chloride, separation of the precipitate of hexahydrated aluminum chloride and of the chlorosulphuric mother liquor charged with impurities, pyrohydrolysis of the precipitate to give the desired pure alumina with recycling of released hydrochloric acid, degassing of the chlorosulphuric liquor of impurities with recycling of the gaseous HCl for chlorination, yielding a sulphuric liquor of impurities, finally the elimination of the impurities present in this latter liquor in the form of a sulphuric precipitation by concentration in the presence of potassium ions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.