摘要
ＮａＡｌＯ２ 溶液和ＣＯ２ 在低温下成胶，生成的沉淀为无定形氢氧化铝、拟薄水铝石或三水氧化铝； 加入一定量的ＮＨ４ ＨＣＯ３ ， 控制一定的时间、温度和压力，氢氧化铝与ＮＨ４ＨＣＯ３ 作用生成片钠铝石ＮＨ４Ａｌ（ＯＨ）２ＣＯ３ ， 经高温焙烧后可制得孔容为０－６ ～１－５ ｍｌ／ｇ 的大孔容氧化铝．
A method for preparing Al 2O 3 with higher pore volume and bigger pore diameter was provided. Al(OH) 3 obtained from neutralization of NaAlO 2 solution by CO 2 at low temperature was mixed with NH 4HCO 3 solution. Under given conditions, the reaction between Al(OH) 3 and NH 4HCO 3 took place and NH 4Al(OH) 2CO 3 was produced. After calcination (600℃/4 h), NH 4Al(OH) 2CO 3 was turned into Al 2O 3. The Al 2O 3 had pore volume more than 0 6 ml/g, and most of the pore volume was in the range of pore diameter between 10～60 nm. The amount of NH 4Al(OH) 2CO 3 in product took much influence on the properties of Al 2O 3. It depended mainly on the treatment conditions, and the type of Al(OH) 3. Higher temperature, longer time and higher n (HCO - 3)/ n (Al 3+ ) value were helpful to the conversion of Al(OH) 3 to NH 4Al(OH) 2CO 3. Amorphous Al(OH) 3 and little crystalline size pseudo boehmite could be easily turned to NH 4Al(OH) 2CO 3 even at below 100℃.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
1999年第2期139-144,共6页
关键词
氢氧化铝
碳酸氢铵
片钠铝石
大孔
氧化铝
aluminum hydroxide, ammonium bicarbonate, ammonium dawsonite, porous alumina
