Abstract: The invention relates to a process for manufacturing highly active, dispersed aluminum hydroxide, of low apparent density. First, unground, very fine grained aluminum tri-hydroxide, of which more than 99% of the grains are at most 3 .mu.m in size, is introduced continuously into a reactor along with a stream of hot dry air, is whirled up and strongly dispersed, heated to 400.degree.-600.degree. C. and shock dehydrated. The low apparent density aluminum oxide flowing out of the reactor in the hot air stream is precipitated out by suitable mechanical means, dispersed in mildly acidic or mildly basic water and rehydrated with the aid of heating. The invention also relates to shaped components of highly active, dispersed low apparent density aluminum oxide having a specific surface area of at least 200 m.sup.2 /g, a pore volume of more than 1.2 cm.sup.3 /g and adequate resistance to fracture and wear.

Abstract: Granular active alumina with high mechanical durability is made by activation of an aluminum hydroxide with an apparent density in the green granular condition of at least 2.20g/cm.sup.3. The green aluminum hydroxide is subjected to compacting by dry compression before activation by a usual heat treatment. Compacting is preferably by running between two rollers.