Process study of CeO2 preparation by jet-flow pyrolysis via microwave heating

Abstract

The spray pyrolysis method has the disadvantage of nozzle plugging, and the conventional heating model causes a large temperature gradient, which leads to unevenly heated reactants. This study used cerium chloride heptahydrate and Venturi reactor as raw material and core equipment. The technology of microwave heating was combined to prepare single-phase sphere-like cerium oxide. The mean size of the particles was near 80nm. The product was characterized via XRD, SEM, and EDS technologies. The purity, morphology, and energy consumption were compared with the conventional spray pyrolysis. Fluent software coupled with HFSS was employed to simulate the effects of different process conditions on products? purity and temperature field in the reactor. There was good correspondence between experimental and simulated results. The results showed that as gas velocity Vg increased, the tendency of the temperature field distribution did not change. The lowest mass fraction of chlorine element reached 0.13% when the gas inlet velocity reached 1.7 m/s. When the material inlet velocity was 0.05 m/s, the mass fraction of the chlorine element was below 0.1%, which indicated that the reactants had a complete reaction. It has been calculated that the heating cost, energy consumption, and CO2 emission decreased sharply compared with the spray pyrolysis method.