Process for the preparation of high purity aluminas starting from impure aluminum chloride solutions
US4486402A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 15, 1982 |
| Grant date | Dec 4, 1984 |
| Priority date | — |
| Expiry date | Dec 15, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/12
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Process for the preparation of high purity alumina containing less than 0.1 weight percent of residual chlorine starting from impure aluminum chloride solutions, which process comprises a crystallization step to provide aluminum chloride hexahydrate crystals having a diameter of from about 400 to about 4000 micrometers in the presence of hydrochloric acid; washing the aluminum chloride hexahydrate crystals so obtained with pure hydrochloric acid; and pyrohydrolyzing the washed crystals of aluminum chloride hexahydrate at a temperature of from about 700.degree. to about 1300.degree. C., in which pyrohydrolysis a gas is forced through a layer of the washed aluminum chloride hexahydrate so as to remove the gaseous reaction products while obviating any possible movement of the solid by the gas, the process particularly producing transition aluminas simultaneously having a specific surface area greater than 100 m.sup.2 /g and a chlorine content less than 0.1 weight percent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.