Catalyst System and a Process for the Production of a Polyethylene in the Presence of this Catalyst System

A process for the production of polyethylene polymerisation in the presence of a catalyst comprising:

• a) a solid reaction product obtained by reaction of:
• 1) a hydrocarbon solution comprising
• (a) an organic oxygen containing magnesium compound or a halogen containing magnesium compound and
• (b) an organic oxygen containing titanium compound and
• 2) a mixture comprising a metal compound having the formula MeRnX3-n wherein X is a halogenide, Me is a metal of Group III of Mendeleev's Periodic System of Chemical Elements, R is a hydrocarbon radical containing 1-10 carbon atoms and 0≦n≦3 and a silicon compound of formula RmSiCl4-m wherein 0≦m≦2 and R is a hydrocarbon radical containing 1-10 carbon atoms wherein the molar ratio of metal from (b):
• titanium from (a) is lower then 1:1 and
• b) an organoaluminium compound having the formula AlR3 in which R is a hydrocarbon radical containing 1-10 carbon atoms.

A process for the production of an ethylene polymer having an average molecular weight higher than 280000 g/mol and lower than 10000000 g/mol. an average particle size (D50) in the range between 50 and 250 micrometer and a bulk density in the range between 350 and 600 kg/m3 comprising polymerisation in the presence of a catalyst comprising:

• a) a solid reaction product obtained by reaction of:
• 1) a hydrocarbon solution comprising
• (a) an organic oxygen containing magnesium compound or a halogen containing magnesium compound and
• (b) an organic oxygen containing titanium compound and
• 2) a mixture corn rising a metal compound having the formula MeRnX3-n wherein X is a halogenide, Me is a metal of Group III of Mendeleev's Periodic System of Chemical Elements, R is a hydrocarbon radical containing 1-10 carbon atoms and 0≦n≦3 and a silicon compound of formula RmSiCl4-m wherein 0≦m≦2 and R is a hydrocarbon radical containing 1-10 carbon atoms wherein the molar ratio of metal from (b):
• titanium from (a) is lower then 1:1 and
• b) an organoaluminium compound having the formula AlR3 in which R is a hydrocarbon radical containing 1-10 carbon atoms.