Patent ID: 7659223

Claim:
A process for preparing an olefin polymerization catalyst component in the form of particles having a predetermined size range, said process comprising the steps of: a) preparing a solution of a complex of a Group 2 metal and an electron donor by reacting a compound of said metal with said electron donor or a precursor thereof in an organic liquid reaction medium; b) adding said solution of said complex to at least one compound of a transition metal to produce an emulsion, the dispersed phase of which contains more than 50 mol % of the Group 2 metal in said complex; c) agitating the emulsion in order to maintain the droplets of said dispersed phase within such an average size range of 5 to 200 μm; d) solidifying said droplets of the dispersed phase by heating; and e) recovering the solidified particles of the olefin polymerization catalyst component; wherein an aluminum alkyl compound of the general formula AlR 3−n X n wherein R stands for a straight chain or branched alkyl group having 1 to 20 carbon atoms; X stands for halogen; and n stands for 0, 1, 2 or 3, is added and brought into contact with the droplets of the dispersed phase of the agitated emulsion before recovering the solidified particles in step e).