Granule based on pyrogenically prepared silicon dioxide, its preparation and catalyst support containing the same

PROBLEM TO BE SOLVED: To obtain granules for catalyst carriers which are based on pyrogenically prepd. SiO 2 and have a specific average grain size, BET surface area, pore volume, pore size distribution, pH value and tapping density. SOLUTION: The SiO 2 produced by an in-flame hydrolysis from SiCl 4 is dispersed into water to prepare a dispersion of about 5 to 25 wt.% in concn. The dispersion is spray dried at about 200 to 600°C. The resulted SiO 2 granules are heated for 6 to 8 hours at 150 to 1100°C and a silanizing agent, such as trimethoxyoctylsilane, is sprayed thereto. The granules are then heated for 0.5 to 6 hours at about 105 to 400°C, by which the SiO 2 based granules having the physicochemical characteristics of the average grain size of 10 to 120 μm, the BET surface area of 40 to 400 m 2 /g, the pore volume of 0.5 to 2.5 ml/g, the pore size distribution: the pores of the diameter <5 μm are ≤5% of the total pore volume and the balance meso- and macropores, the pH value of 3.6 to 8.5 and the tapping density of 220 to 700 g/L are obtd. These granules are used as the catalyst carrier for PE production. COPYRIGHT: (C)1996,JPO