Catalytic solid for use in the polymerization of alpha-olefines, process for preparing it and process for the polymerization of alpha-olefines in the presence of a catalyst system containing this solid

摘要

The invention concerns: a catalytic solid containing magnesium, a halogen, titanium and silicon, this catalytic solid also containing aluminium and being microporous; a process for preparing this catalytic solid; use of this catalytic solid for polymerising alpha-olefines.