高比表面积窄孔分布氧化铝的制备 Ⅰ.沉淀条件的影响  

Preparation of Alumina with High Specific Surface Area and Narrow Pore Size Distribution Ⅰ. Effect of Precipitation Conditions

作　　者：杜明仙[1] 翟效珍[1] 李源[1] 李林东[1] 朱华青[1] 谭长瑜[1] 

机构地区：[1]中国科学院山西煤炭化学研究所,山西太原030001

出　　处：《催化学报》2002年第5期465-468,共4页

基　　金：抚顺石油化工公司资助项目

摘　　要：以硫酸铝液为原料 ,以氨水、氢氧化钠和铝酸钠为碱沉淀剂 ,采用pH摆动法制备了高比表面积、大孔径、窄孔分布、大孔体积氧化铝 ,考察了沉淀剂、沉淀温度及沉淀时酸侧pH值对氧化铝物性的影响 ,并对 pH摆动法与等 pH沉淀法的结果进行了比较 .结果表明 ,通过改变制备参数可以获得高比表面积、大孔体积的氧化铝 ,当沉淀温度为 70℃ ,pH摆动 3或 4次时 ,氧化铝的孔体积可高达 1 0ml/ g,比表面积仍大于 30 0m2 / g.用 pH摆动法制得的样品比用等 pH沉淀法制得的样品容易酸溶 ,对挤压成型有利 .不同样品在酸溶液中的分散性表明 ,用氨水沉淀剂可获得相对较小的沉淀粒子 .改变沉淀时酸侧的pH值 。The development of processing technology for heavy oil demands that the catalyst support has better properties. The alumina with high specific surface area, large pore volume and diameter, and narrow pore size distribution was prepared by pH swing method from Al 2(SO 4) 3 and different precipitants such as NH 4OH, NaOH and NaAlO 2. The effects of precipitants, precipitation temperature and pH value on the properties of alumina were studied. The alumina precipitated by pH swing and by constant pH value was compared. The experimental results showed that the alumina with better properties can be obtained by changing the preparation parameters. The alumina had about 1.0 ml/g pore volume as well as 300 m 2/g specific surface area when the pH swing times were three or four and the precipitation temperature was 70 ℃. The samples precipitated by pH swing method have more narrow pore size distribution and higher acid dispersibility, and are more easy to be extruded into catalyst support than those by constant pH method. Though the alumina precipitated by constant pH method has similar pore structure to those by pH swing method, it is sandy and has heavier bulk density. The experimental results indicated that the sample precipitated by NH-4OH has higher acid dispersibility than that by NaOH or NaAlO 2 precipitant. NH 4OH precipitant can produce smaller and more homogeneous precipitated particles and more narrow pore size distribution than other precipitants. The pore volume of alumina decreased, the pore size distribution became more narrow, and the particles became smaller when pH value on acid-side decreased from 3.0 to 2.5.

关 键 词：氧化铝 比表面积 窄孔分布 pH摆动法 沉淀条件 硫酸铝 催化剂 载体 

分 类 号：TQ426.95[化学工程]