滴定速率对制备纳米NH_4 AlO(OH)HCO_3的影响

Effects of titration speed on preparing nano-NH_4AIO(OH)HCO_3

以NH_4Al(SO_4)_2和NH_4HCO_3为主要原料,采用均相沉淀法制备纳米Al_2O_3前驱体NH_4AlO (OH)HCO_3(AACH),研究了滴定速率对其制备的影响。结果表明:将硫酸铝铵溶液滴入剧烈搅拌的碳酸氢铵溶液中,滴定速率不同,产物的组成和尺寸大小不同。滴定速率较低时,产物为晶化完全、纯净的AACH相,滴定速率较高时,产物中含有极少γ- AIOOH,而且滴定速率越低,所得前驱体尺寸越小。

NH4 AlO（OH） HCO3, the precursor of nano- Al2O3, was prepared by homogeneous precipitation method using NH4 Al（SO4）3 and NH4 HCO3 as raw materials. Effects of titration speed on preparing precursors were identified in the paper. The results indicate that titration speed has a great influence on preparing precursors.Nano-NH3 AlO（OH）HCO3 is prepared by adding an aqueous solution of N H4 Al（SO4）3 drop by drop to an aqueous solution of NH4 HCO3 at a titration speed of 3ml/min. When titration speed is low, the product is pure AACH crystals. When titration speed is high, the product contains γ-AIOOH little. And titration speed is lower,the size of precursors is smaller.