| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a cerium-based oxide by which ceric oxide having excellent heat resistance in a specific surface area can stably be produced by using an inexpensive apparatus. SOLUTION: In the method for producing the cerium-based oxide, including at least (1) a process for adjusting the concentration of free acid in a solution containing a cerium salt, (2) a process for adding and dissolving urea in the solution, (3) a process for forming cerium hydroxide by heating the solution, (4) a process for filtering the cerium hydroxide, and (5) a process for firing the cerium hydroxide, when addition equivalent of urea in the process of (2) is defined as X [X (equivalent) = ((urea addition amount)-(urea amount required for neutralizing free acid))/(urea amount required for forming cerium hydroxide)], X is set to be at least 3. COPYRIGHT: (C)2008,JPO&INPIT |
