Method for preparing high-purity lamellar single crystal and lamellar crystal compact aggregated cerium carbonate

The invention relates to a method for preparing high-purity lamellar single crystal and lamellar crystal compact aggregated cerium carbonate. Ammonium citrate is added in advance to regulate and control the crystallization process when cerium is precipitated by using ammonium (hydrogen) carbonate. The molar ratio Rab of the ammonium bicarbonate to the cerium ions is 5-8, the molar ratio Rac of theammonium carbonate to the cerium ions is 2.5-4, the addition amount of the triammonium citrate is more than or equal to 0.1 percent, and the aging crystallization time is more than or equal to 4 hours; and along with the increase of Rab and Rac, the chlorine content in the product is reduced, and the cerium carbonate lamellar single crystal with the chlorine content of less than or equal to 50mg/kg is converted into the ceric ammonium carbonate double salt lamellar crystal compact aggregate with the chlorine content of less than or equal to 20mg/kg. For the cerium carbonate flaky single crystal, the addition amount o