碳酸氢铵沉淀法制备超细CeO_2粉体工艺条件研究

Study on the Preparation Condition of Ultra Fine CeO_2 by Precipitation Method with Ammonium Bicarbonate

用碳酸氢铵从硝酸铈溶液中沉淀制备了超细C eO2粉体,研究了沉淀工艺条件对制备C eO2的一次粒径、团聚粒径以及粉体团聚性的影响。研究表明形成的碳酸铈胶状沉淀物需要在高温下陈化足够长的时间才能制备出一次粒径小,分散性好的C eO2产品,否则将形成大的团聚体。当碳酸氢铵与硝酸铈的摩尔比为3∶1左右、沉淀温度为50℃左右时制备的C eO2具有小的一次粒径,而且产品的分散性好。适当地增大加料速度和初始料液的pH值有利于减小C eO2的一次粒径和团聚性。

Ultra-fine CeO2 was prepared from cerium nitrate solution by precipitation method with ammonium bicarbonate. The influence of the preparing conditions on the primary particle size, aggregated particle size and aggregated degree of CeO2 was studied. The results show that it needs high aging temperature and enough aging time for the colloidal precipitate of cerium carbonate to get the relatively small primary particle size of CeO2 with good dispersion, otherwise large aggregate will form. As the molar ratio of NH4HCO4 to Ce （NO3）3 is about 3 ： 1 and the precipitation temperature is about 50℃, the prepared CeO2 has small primary particle size and good dispersibility. Moderate increase of the feeding rate and the pH of initial solution is preferable to decrease the primary particle size and aggregation of CeO2.