Preparation of ceria with large particle size and high appearance density

Cerium is one of the most abundant rare earth elements in both bastnasite and monazite. Ceria has been widely used in optical, catalytic, electrolyte, and sensor materials, with unique performances. With the development of functional materials, great interest has been focused on the synthesis and characterization of specific fine/mesoporous ceria powder. In this study, the modified precipitation and recrys-tallization processes combined with a controlled calcination process for fabricating the ceria with large particle size and high appearance density was reported. During precipitation, a certain amount of mineral acid such as nitric acid served as an additive, to adjust the precipitation and crystallization processes of cerium oxalates. An appropriate acidic condition could lead the process into the Oswald ripening stage and made the particles become bigger. Thus, the appearance density of powder was increased. The optimized conditions, such as the temperature, feeding speed, type and concentration of mineral acids, and the concentration of cerium-contained stock solution, were investigated and evaluated.