| abstract |
A method for activating supported chromium oxide catalysts in which a chromium-containing catalyst on a silica-containing base is first heated in an oxidizing atmosphere at temperatures up to about 850° C. and then cooled down. During the cooling step of the catalyst, the oxidizing atmosphere is replaced by a non-oxidizing one, leading to an activated catalyst. A process for the polymerization of alpha-olefins, especially ethylene, in which at least one alpha-olefin is contacted, under polymerization conditions, with the catalyst activated by the method described above. |