PROCESS FOR PREPARING A CATALYST COMPONENT

摘要

The present invention relates to a catalytic system for the polymerization of alpha-olefins consisting of a) an aluminium compound chosen among those of formula AlR3 or AlRxY3-x, wherein R is a lower alkyl radical, Y is an halogen or hydrogen atom, and x is a number between 1 and 2, and b) a titanium compound finely dispersed on a carrier having a high surface area, which carrier has been previously treated with a magnesium inorganic compound of the formula MgX2.nH2O, wherein X represents a halide and n is a number ranging from 0 to 6, in which catalyst the amount of magnesium dispersed on the carrier is ranging from 0.1 to 10% by weight and the molar ratio of aluminium to titanium is ranging from 20 to 75. The invention also relates to a method for preparing this catalytic system which has a high activity and remains unimpaired in time.