【摘要】 以尿素为沉淀剂制备纳米晶镁铝水滑石,其结晶生长机理与粒径无关。从相变驱动力、晶种与晶体形成、成核速率和晶体生长速率3个方面研究了纳米晶镁铝水滑石的结晶动力学,求出不同温度下成核速率、晶体生长速率及其相应的表观活化能,并确定其动力学模型。结果表明影响晶粒形成和生长的主要因素是晶化温度和反应物过饱和度。当x(Mg)∶x(Al)=3、晶化温度120℃、晶种Al(OH)3、晶种用量3.0%时可快速得到较好的层状纳米晶镁铝水滑石。更多还原

【Abstract】 Nanocrystaline Mg-Al hydrotalcite was prepared as the catalysts using urea.The mechanism of crystal growing nanocrystaline Mg-Al hydrotalcite had no relation with crystal grain size.Crystalization kinetics for namocrystaliztion Mg-Al hydrotalcite was discussed in the views of phase transition force,seed and crystalline forming,nucleation rate and crystal growth rate.The nucleation rate,crystal growth rate and apparent activation energy were obtained with different temperature and confirmed the crystalization kinetics model.It was concluded that the primary reasons which influnced the forming and growth of crystalline were temperature of crystallinity and oversaturation of reactants.The better samdwich Nanocrystaline Mg-Al Hydrotalcite can be easily received when Mg∶Al was 3,temperature of crystalline was 120℃,the seed of crystalline was Al(OH)3 and the dosage was 3.0%.更多还原