干燥方式对油页岩灰渣制备SiO_2气凝胶性质的影响

INFLUENCE OF DRYING METHODS ON PHYSICAL PROPERTIES OF SILICA AEROGEL PREPARED FROM OIL SHALE ASH

以油页岩灰渣为原料,结合微波干燥、热风干燥和烘箱干燥3种方式在常压下成功地制备了SiO2气凝胶,研究了干燥方式对气凝胶性质的影响。结果表明:3种干燥工艺都能制备出性能较好的气凝胶,密度为0.0703~0.112 g/m3,比表面积为718~1360 m2/g,孔体积为2.37~4.29 m3/g,孔径为11.8~14.1 nm。其中微波干燥制备气凝胶弥补了传统的烘箱干燥使凝胶受热不均而产生温度梯度的缺点,缩短了干燥时间,减少了粉体团聚,使气凝胶尽可能保持了原有的孔结构。

In this paper,oil shale ash as raw materials,combined microwave drying,hot air drying and oven drying at atmospheric pressure in three ways successful SiO2 aerogels prepared to study the effects of three drying methods on the nature of the airgel.The silica aerogels based on oil shale ash were successfully synthesized via microwave drying,hot air drying and oven drying at atmospheric pressure,respectively.The results indicated that all the silica aerogels prepared via different methods were nanoporous material with the meshwork structure,the BET surface area of 718 ~1360 cm2/g,tapping density of 0.0703 ~ 0.112 g /cm3,pore diameter of 11.8 ~14.1 nm.This method compensated for the shortcomings of oven drying of the temperature gradient,shortened drying time and reduced the agglomeration of the powders,so the aerogels maintained the original pore structure as much as possible.