Green synthesis of ceria powders with special physical properties by carbon dioxide carbonization

Abstract

In order to improve the application values of Ce element, in this paper, rare earth chloride solution was used as raw material, the pH value was controlled by inorganic alkali, the ceria powders with special physical properties were prepared by carbon dioxide carbonization method. According to characterization of SEM, XRD, and TG-DSC, Ce(OH)3 prepared at pH = 7.5 exhibits smaller particle size than that prepared at other conditions. CeO2 precursor obtained by direct carbonization of Ce(OH)3 shows smaller particle size and narrow size distribution, CeO2 precursor forms at first by carbonization of Ce(OH)3 with the continuous addition of CO2 gas, and the chemical component is indicated to be Ce2O(CO3)2·6H2O. Cubic phase CeO2 powders are obtained by calcined at 750 °C for 4 h. The mean particle size D50 is 0.941 μm, and particle size distribution is smaller than 1. The microscopic appearance is homogeneous, with a spherical-like shape and a grain size of 200–500 nm. The light quality characteristics of sedimentation volume and accumulation density are obviously better than those of carbonate precipitation products. The carbonization method can be used not only to obtain ultra-fine rare earth oxides with fine particle size, narrow distribution and high dispersion properties, but also to achieve the reuse of carbon dioxide greenhouse gas.