PRODUCTION OF METAL OXIDE PARTICLES

PURPOSE:To easily produce a spherical metal oxide having very high single dispersibility and a large average particle diameter in a short time by discharging part of the alkaline reacted aq. soln. into the outside of the system or keeping the volume of the soln. constant in the hydrolyzing process in the process of hydrolyzation of a hydrolyzable organometallic compd. while dropping an alkaline aq. soln. on the compd. CONSTITUTION:A hydrolyzable organometallic compd., preferably alkoxysilane or a low condensation product obtd. by partially hydrolyzing it, especially preferably tetramethoxysilane or tetraethoxysilane is hydrolyzed while dropping an alkaline aq. soln. on the compd. so that 1-6 times (by mol) as much water as the metallic element is added. The aq. soln. is made alkaline with a base, preferably ammonia. In the hydrolyzing process, part of the alkaline reacted aq. soln. is discharged into the outside of the system, e.g. by thrusting a tube and drawing out a part of the soln. or the volume of the soln. is kept constant by continuously drawing out the soln. by a volume corresponding to the total amt. of the soln. dropped.