FOER FARING FRAMSTAELLNING AV EN BAERARKATALYSATOR FOER POLYMERISATIONAV A-OLEFINER

摘要

Process for the preparation of a supported catalyst for the polymerisation of alpha -olefins, in which (1) a support gel containing silicon dioxide is prepared by (1.1) introducing a sodium or potassium waterglass solution into a rotating stream of an aqueous mineral acid both longitudinally and tangentially to the stream, spraying the silicic acid hydrosol thus formed in droplet form into a gaseous medium, allowing it to solidify into a hydrogel and freeing the hydrogel thus obtained of salt by washing without prior aging, (1.2) drying the hydrogel resulting from (1.1) to form the support gel, and (2) the support gel (1) is loaded with chromium trioxide or a chromium compound which can be converted into chromium trioxide under the conditions of the process step (3), which results in a chromium-containing support gel, and (3) the chromium-containing support gel (2) is heated in an anhydrous gas stream containing oxygen in a concentration of over 10% by volume for from 10 to 1000 minutes at from 400 to 1100 DEG C, the hydrogel resulting from the process step (1.1) being dried in the process step (1.2) over a time of not more than 60 seconds in a shaping flash dryer at an inlet temperature of from 80 to 400 DEG C .