Process for preparing spherical polymerization catalyst components for use in olefin polymerizations

A method of making a solid catalyst component for production of a polyolefin, comprising

• a) dissolving a halide-containing magnesium compound in a mixture comprising alkylepoxide, an organic phosphorous compound, a carboxylic acid or anhydride, and a hydrocarbon solvent to form a homogenous solution;
• b) optionally treating the homogeneous solution with a halogenating agent;
• c) treating the homogenous solution with a first titanium halide compound in the presence of a surface modifier and optionally a first electron donor to form a solid precipitate, wherein, if present, the first electron donor is an ether;
• d) optionally treating the solid precipitate with a second electron donor;
• and
• e) treating the solid precipitate with a second titanium halide compound and optionally with a second electron donor to form the solid catalyst component,
• wherein step b) is performed and/or the first electron donor is present in step c).