Method of obtaining pure alumina by acid attack on aluminous minerals containing other elements
US4177242A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 9, 1978 |
| Grant date | Dec 4, 1979 |
| Priority date | — |
| Expiry date | Feb 9, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01F7/74
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of obtaining alumina of high purity from aluminous mineral containing impurities by attacking the mineral with a sulphuric acid liquor and separating the resulting liquor from a residue which remains after the attack, the steps of PA1 (a) mixing the resulting liquor with a liquor containing HCl and H.sub.2 SO.sub.4, PA1 (b) introducing HCl gas into the mixture, PA1 (c) cooling the mixture from step (b) to precipitate hydrated aluminum chlorosulphate crystals having the formula AlSO.sub.4 Cl.6-7H.sub.2 O, PA1 (d) separating the hydrated crystals of hydrated aluminum chlorosulphate from the mother liquor, PA1 (e) heating the separated crystals to a temperature that does not exceed 600.degree. C. to yield a mixture of aluminum sulphates and hydrochloric gases, PA1 (f) thermally decomposing the aluminum sulphates to yield alumina of high purity and sulphuric gases, PA1 (g) degassing the mother liquor of step (c) to yield HCl gas, PA1 (h) concentrating the mother liquor from step (f), PA1 (i) freeing the concentrate from impurities, and PA1 (j) recycling the mother liquor from step (h) to the attack on the aluminous mineral.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.