Ziegler-natta catalyst compositions for producing polyethylenes with a high molecular weight tail and methods of making the same

A method of making a polyethylene polymer containing from about 1% to about 10% of a high molecular weight tail above molecular weight 1,000,000, the method comprising polymerizing ethylene, and optionally, a C3 to C8 α-olefin, with a catalyst system comprising a catalyst component, a halogenating agent;

• and an activating co-catalyst, wherein the catalyst component is made by a method comprising:
• a) contacting in a slurrying agent:
• i) at least one magnesium dihydrocarbyl oxide;
• ii) at least one Lewis acidic solubilizing agent;
• and
• iii) at least one titanium compound;
• and
• b) spray drying the slurry of step a) to evaporate the slurrying agent and to produce solid particles;
• where the magnesium dihydrocarbyl oxide and the titanium compound are present in the slurry in a molar ratio of magnesium to the total moles of the titanium compound and any transition metal compound(s) different than the titanium compound is from about 2 to about 60;
• and
• wherein the method of making the catalyst component further comprising step c), as follows:
• c) contacting the solid particles of step b) with:
• i) one mild first halogenating agent selected from SiCl4 and SiCl4/TiCl4 and ii) one strong second halogenating agent of R8AlCl2, where R8 ethyl, in succession.