Olefin polymerization catalyst and catalyst support

Claim 1

An olefin polymerization catalyst prepared by the steps of: a. reacting a zirconium compound of the formula M 4 Zr(C 2 O 4 ) 4 .nH 2 O, where M is an alkali metal or ammonium ion and n equals 0 to 10, with a silicon compound of the type A 2 SiO 3 , where A is an alkali metal, in an aqueous solution at a pH of at least 11 and then adding an acidic material to a pH of about 5-9, to produce a hydrocogel; b. aging said hydrocogel at a temperature between about ambient to 90° C. for at least one hour; c. washing said hydrocogel of b with an aqueous liquid; d. partially dehydrating the resulting washed hydrocogel of c by azeotropic distillation by mixing with a compound capable of forming an azeotrope with water or by washing the hydrocogel with a water miscible solvent to produce a substantially water-free, large pore volume zirconia-silica catalyst support; e. removing residual water from the product of d by chemically reacting this water with a ketal of the formula RC(OR) 2 R in which R is the same or different and is hydrogen or an alkyl group of 1-5 carbon atoms; f. calcining the resulting zerocogel at a temperature of about 1000°-1850° F. preparatory to its use as an olefin polymerization catalyst support; g. introducting a chromium compound onto said calcined support of f; and h. activating to produce an active polymerization catalyst.