PRODUCTION PROCESS OF TITANIA-SILICA MIXED CRYSTAL PARTICLES HAVING A HIGH BULK DENSITY, TITANIA-SILICA MIXED CRYSTAL PARTICLES OBTAINED BY THE PROCESS AND USES THEREOF

摘要

A process for producing titania-silica mixed crystal particles having a high bulk density and comprising titanium oxide as the main component and silicon oxide as a subsidiary component, the process comprising decomposing a gaseous titanium halide and a gaseous silicon halide, each heated at 600° C., or more in the presence of oxygen or water vapor heated at 600° C. or more, heating the obtained powder at 300 to 600° C. to decrease the concentration of raw material-originated hydrogen halide in the powder to 1 mass % or less, and then subjecting the powder to a treatment of dissociating the aggregated or steric structure.