| 摘要 |
A process for the preparation of an activated catalyst for the polymerization of olefins, includes mixing, in the absence of a solvent, at least one chromium salt with a support composition including at least one compound (A) which is an inorganic, oxygen-containing compound of at least one element selected from the group consisting of Group IVb, IIIa and IVa, and at least one compound (B) which is an inorganic compound containing at least one element selected from the group consisting of Group IVb and IIIa, the at least one compound (B) being different from the at least one compound (A); preactivating the mixture by heating in an oxidizing atmosphere at a temperature which is lower than the melting temperature of the at least one chromium salt to obtain a catalyst precursor; and activating the catalyst precursor by calcining in an oxidizing atmosphere and under conditions such that part of the chromium is converted to hexavalent chromium.
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