Process for obtaining pure alumina by the hydrochloric attack of aluminous ores and extraction of the impurities by means of a sulphuric treatment
US4237102A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1979 |
| Grant date | Dec 2, 1980 |
| Priority date | — |
| Expiry date | May 8, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/80
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A cyclic process for obtaining very pure alumina by the hydrochloric acid attack of a silico-aluminous material, the said process comprising, in a first stage, the precipitation of at most 75% of the alumina present in the liquor originating from the attack in the form of hexahydrated aluminum chloride which is subsequently decomposed by heating, then, in a second stage, the treatment of the liquor leaving the first stage with HCl gas in order to precipitate dissolved Al.sub.2 O.sub.3 in the form of hexahydrated aluminum chloride which is recycled into the liquor leaving the attack, while the hydrochloric liquor leaving the second stage and impoverished in Al.sub.2 O.sub.3 but rich in impurities, is treated with a recycled sulphuric liquor in order to precipitate impurities as their corresponding sulphates.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.