Cerium dioxide with large particle size prepared by continuous precipitation

Cerium dioxide (CeO2) has attracted much attention and has wide applications such as automotive exhaust catalysts, polishing materials for optical glasses and additives for advanced glasses, as well as cosmetic materials. The particle size and its distribution are key factors to the performance of the materials in the functional applications. However, control of particle size is still a challenge in materials synthesis. Therefore, continuous precipitation of cerium oxalate (precursor of ceria) was carried out at different operational conditions such as reactant concentration, agitation speed, feeding rate and reaction temperature, and their effect on the particle size distribution, distribution width and morphology of cerium oxalate were investigated. The optimum conditions for preparing cerium oxalate with large particle size were determined based on orthogonal test as follows: [Ce(NO3)]=0.02 mol/L, agitation speed: 200 r/min, feeding rate of solutions of cerium nitrate and oxalic acid: 10 ml/min, reaction temperature: 80 °C. The results showed that the shape of cerium oxalate was sheet and the phase structure was amorphous. The median particle size of the final product was 27.60 μm, the particle size distribution width was very narrow and the micrograph was still sheet-like. Some attempts were made to explain the experimental phenomena in terms of agglomeration, disrupt, and precipitation kinetics.