| 摘要 |
PURPOSE: Provided is a preparation method of high purity(>=99%) ceric ammonium nitrate by controlling cerium concentration and acidity of nitric acid in the processing of intermediate preparation and crystallization of cerium compound. CONSTITUTION: The preparation method comprises the steps of: dissolving a salt(carbonate, nitrate, chloride, etc.) or an oxide of Ce3+ and Ce4+, such as Ce(NO3)3, Ce(OH)2 or CeO2, into an aqueous HNO3 solution to be a Ce ion/HNO3 molar ratio of 3-12.5; changing Ce3+ into Ce4+ by adding an oxidant; controlling the concentration of Ce and HNO3 to be 8-81g/L and 0.05-0.8N, respectively by adding deionized water and/or volatilizing HNO3 in cerium/nitric acid solution, which results in precipitating cerium compound, Ce(OH)x(NO3)y·nH2O(x+y=4); filtering; dissolving precipitates into nitric acid solution to be a CeO2/HNO3 molar ratio of 1.26-5.075; adding excess ammonium nitrate and optionally nitric acid solution and deionized water to be Ce4+ of 20g-200g/L and HNO3 of 0.5-9N under the pressure of 1-650mmHg at 65-115deg.C; concentrating at a stirring rate of 350cm/sec for deposition of ceric ammonium nitrate; filtering, washing with water, HNO3 or organic solvent and drying under 85deg.C. |
