Patent ID: 8795623

Claim:
A method for preparing cerium carbonate comprising: continuously introducing a reaction solution comprising a cerium precursor and urea in a tubular reactor including an inlet, an outlet, and one or more reaction tubes through the inlet; reacting the cerium precursor with urea at an elevated temperature in the reaction tube; and continuously discharging cerium carbonate formed by the reaction of the cerium precursor and urea to the outlet, wherein during the continuous introduction of the reaction solution, the reaction solution is continuously introduced at a speed enabling residence of the reaction solution in the reaction tube for a residence time satisfying the following Mathematical Formula 1, wherein the residence time of the reaction solution in the reaction tube is 5 to 15 minutes, the concentration of the cerium precursor in the solution is 0.1 to 3 mol/L, and the reaction tube has a diameter of 0.25 to 5 inches: Residence time(min)≧20000·[{concentration(mol/L)·diameter(inch)}/temperature(° C.)] [Mathematical Formula 1] in the Mathematical Formula 1, “residence time (min)” represents a period of time (min) during which the reaction solution resides in the reaction tube, “concentration (mol/L)” represents molar concentration of the cerium precursor in the reaction solution, “diameter (inch)” represents diameter (inch) of the reaction tube, and “temperature (° C.)” represents an internal temperature of the reaction tube when the reaction solution is introduced.