Effects of preparation conditions on morphology of Al_2O_3 precursor and pore size distribution of Al_2O_3

Abstract：A series of Al（OH）3were prepared by a coprecipitation-sol technology from Al2（SO4）3and NH4HCO3precipitates.The effects of preparation conditions of Al2O3 precursor on pore size distribution of Al2O3 were studied by orthogonal tests.The alumina and the precursor were characterized by surface area and pore size analyzer and TEM,respectively.The results show that the preparation of precursor with high dispersion is of great significance in preparing Al2O3 with concentrated pore distribution.The order of effects of precursor formation condition on the pore distribution of Al2O3 is as follows： aging timeexcess coefficient（pH）reaction temperaturefeeding wayAl3＋ concentration.The effects of the molding pressure,calcining temperature and binder on pore size distribution of Al2O3 were researched by orthogonal tests as well.The surface area and pore size test suggest that the high pressure results in the formation of defective pores,and the pore size distribution is of double-structure,which indicate that the high pressure is not of benefit to the formation of Al2O3 particles with concentrated pore size distribution.The order of effects on pore size distribution is as follow： molding pressurecalcining temperaturebinder.According to the conditions defined by the orthogonal tests,the Al2O3 with the concentrated pore size distribution from 5 to 10 nm was prepared.