Process for the preparation of light, highly activated dispersed aluminium oxide, shaped products of light aluminium oxide and process for the preparation of the shaped products.

摘要

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 DEG -600 DEG 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 m2/g, a pore volume of more than 1.2 cm3/g and adequate resistance to fracture and wear. The shaped components are in particular produced by treating low apparent density aluminum oxide with rehydrated grains and extruding as a pliable mass, or by rolling the low apparent density aluminum oxide grains in a cumulative granulation process in which water is added during granulation.