Method for producing a polyolefin

A method for producing a polyolefin comprising polymerizing ethylene or ethylene and other α-olefin in the presence of a catalyst comprising a transition metal compound and an organometallic compound, wherein a catalyst system is used which comprises:

• (A) a solid catalyst component prepared by reacting a homogeneous solution containing
• (I) metal magnesium and a hydroxylated organic compound,
• (II) at least one zirconium compound of the formula Zr(OR1)4, wherein R1 is a hydrocarbon group having 1 to 20 carbon atoms, and
• (III) at least one silane of the formula Si(OR4)4 wherein R4 is a hydrocarbon group having 1 to 12 carbon atoms, with
• (IV) at least one organoaluminum halide compound to obtain a solid product, isolating the solid product, and reacting this solid product with
• (V) TiX4, wherein X is a halogen atom, and
• (VI) at least one compound selected from the group consisting of silicon halides, hydrocarbon halides, aluminum halides and boron halides, and
• (B) at least one organoaluminum compound, wherein
• the ratio of magnesium atom of reactants (I) to zirconium atom of reactant (II) is from 1:0.05 to 1:5,
• the ratio of magnesium atom of reactant (I) to silicon atom of reactant (III) is from 1:0.05 to 1:5,
• the ratio of magnesium atom of reactant (I) to aluminum atom of reactant (IV) is from 1:1 to 1:20 and
• the ratio of magnesium atom of reactant (I) to titanium atom of reactant (V) is from 1:0.1 to 1:10:
• and the ratio of magnesium atom of reactant (I) to compound (VI) is from 1:01 to 1:10.