GB945403A - Improvements in or relating to the production of alumina - Google Patents

Abstract

Eta-alumina is produced by spraying a mixture of alcoholates, obtained by reacting aluminium triethyl with ethylene at a temperature between 65 DEG and 150 DEG C. and a pressure from 200 to 5,000 p.s.i.g. and oxidizing the reaction product with a gas containing free oxygen, on to the surface of an agitated body of water maintained above 50 DEG C. thereby forming separate phases of hydrated alumina slurry and alcohols, separating the alumina slurry from the alcohols, and thereafter drying and calcining to form eta-alumina. Any alchols contained in the hydrated alumina slurry may be removed by leaching with a suitable solvent, e.g. diethyl ether, methanol, butanol or acetone, by stripping with an inert stripping medium, e.g. steam or nitrogen, or by a combination of solvent extraction and stripping. The alcohol phase, after separation, may be further treated to remove the water from the alcohols and to further separate the individual alcohols. Any conventional spray or atomizing nozzle may be used to subdivide the alcoholates. Further subdivision is aided by the use of an atomizing gas which can be any inert gas. The dried hydrated alumina, which is mainly a -alumina monohydrate may be calcined at a temperature between 600 DEG and 1,200 DEG C. for 0.5 to 24 hours to form etaalumina.