SOL-SPRAY TECHNIQUE FOR FINE-GRAINED CERIA PARTICLES

Submicron-range cerium oxide powders of narrow size distribution have been prepared by spray-drying of a sol derived from cerium nitrate. Ce rium hydroxide is first precipitated by taking care to keep cerium in the Ce3+ state and later peptized to a stable sol at pH 3. The stabili ty of the sol at different pH values was studied by nephelometry. Ther mal-decomposition characteristics of spray-dried cerium hydroxide, the formation of the CeO2 phase, and the physical properties of calcined ceria, including particle size and distribution, are reported. A cryst allite size as small as 100 angstrom could be obtained.