采用水热法，以硫酸铝(Al2(SO4)3∙18H2O)为原料、尿素为沉淀剂，在一定的醇水比例下(体积比2：1)，制备出具有不同形貌的氧化铝前驱体，用SEM、XRD和TG-DSC分析对粉体的微观结构及热分解过程进行了研究。结果表明：相同条件下，水热处理温度影响氧化铝前驱体的微观形貌及向α-Al2O3转变的温度，随水热处理温度的提高，其相结构由无定型态向结晶度高的薄水铝石相转变，而其煅烧产物向α-Al2O3转变的温度逐渐升高。利用Doyle-Ozawa法和Kissinger法计算经水热温度为100、140和160℃处理获得产物热分解过程的表观活化能，通过该两种方法得到的表面活化能平均值分别为150.68、155.46、171.09 kJ/mol。用 Kissinger法确定了反应级数、频率因子和不同水热处理温度下产物的热分解速率方程。%Alumina precursors with different morphologies were synthesized using Al 2(SO4)3·18H2O as reactant, urea as precipitator and mixture solution of ethanol and water (volume ratio of 2:1) as solvent by a hydrothermal treatment method. The microstructures, thermolysis processes of as-synthesized powders were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), differential scanning calorimeter and thermo gravimetric analysis(TG-DSC). The results show that, under the same conditions, hydrothermal temperature affects the morphology of the alumina precursor and the phase transition temperature ofα-Al2O3. With increasing the hydrothermal temperature, their phases change from amorphous to boehmite with high crystallinity, at the meantime, the phase transition temperature ofα-Al2O3 of their calcined products increase gradually. The average apparent activation energies of thermolysis of precursors obtained on three hydrothermal temperature 100, 140 and 160℃ are calculated to be 150.68、155.46 and 171.09 kJ/mol, using the Doyle-Ozawa and Kissinger methods, respectively. The reaction order and frequency factor are determined by Kissinger method. The kinetics equations of thermolysis of precursors obtained at different hydrothermal temperatures are deduced.
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