Method for preparing a spray-dried composition for use as a polymerization catalyst

A method of making a composition comprising spray-dried particles, said method comprising:

• a) providing a solution or mixture comprising components i), ii), iii), and iv) or the reaction product of thereof:
• i) a magnesium halide;
• ii) a solvent selected from the group consisting of ether, ketone and ester compounds;
• iii) a transition metal compound wherein the transition metal is selected from the ouv consisting of metals of Groups 3-10 and Lanthanides;
• and
• iv) an electron donor selected from the group consisting of alcohols, thiols, weakly donating amines and phosphines;
• b) contacting the solution or mixture of step a) with an inert filler comprising substantially spherical particles having a D50 particle size from 1 to about 12 μm to form a slurry, and
• c) spray-drying the slurry to form spray-dried particles.