Abstract: A process for producing active aluminum oxide granulate of high porosity which comprises mixing finely ground aluminum oxide powder with at least one finely ground additive selected from the group consisting of water-soluble salts and non-ionic substances which do not react with aluminum oxide, are not hygroscopic at room temperature and below about 60% relative humidity and do not undergo any phase transformation at temperatures of up to about 100.degree. C. in a ratio by weight of aluminum oxide to additive of from about 90:10 to 30:70, granulating the mixture in the presence of water, ageing the granulate for at least 5 hours at 50.degree. to 100.degree. C., washing out water-soluble additive, drying and activating the granulate at a temperature of from 200.degree. to 500.degree. C.

Abstract: Highly active aluminum oxide characterized by a severely disturbed crystalline structure of .chi.-(chi-)aluminum oxide, a specific surface area of about 260 to 400 m.sup.2 /g according to BET, a residual water content of 2 to 10 % and a water absorption capacity at 50 % relative atmospheric humidity of more than 15 %, and process of producing same by heating aluminum hydroxide to a temperature of 350.degree. to 800.degree.C with a residence time of from 0.1 to 2 seconds in a zone of high turbulence in a hot gas which enters said zone at a temperature of about 500.degree. to 1200.degree.C at an inflow rate of 30 to 150 m/second. These highly active aluminum oxide may be formed into beads by grinding said aluminum oxide to a specified particle size and forming the aluminum oxide under addition of water.