稻壳灰显微结构及其中纳米SiO_2的电镜观察

SEM/TEM study on the microstructure of rice husk ash and nano-SiO_2 in it

对低温稻壳灰纳米尺度的显微结构进行了SEM、TEM(SAD)研究,首次发现稻壳灰由纳米尺度的SiO2凝胶粒子(～50nm)疏松地粘聚而成。稻壳灰结构中除了以往报道过的微米尺度的蜂窝孔(～10μm)外,还含有大量由SiO2凝胶粒子非紧密粘聚而形成的纳米尺度孔隙(<50nm)。纳米尺度的SiO2粒子和纳米尺度的大量孔隙是稻壳灰具有巨大的比表面积(50～100m2/g)和超高火山灰活性的根本原因。

The nano microstructure of rice husk ash(RHA) burned at 600℃ was first revealed by using SEM/TEM. The results showed that RHA consists of nano SiO2 particles(～50nm) sticking slackly each other. Besides microncellular pores, there were many nano interstitial pores(<50nm ) formed by the packing of nano SiO2 particles. The nano SiO2 particles and nano pores were the basic factors why RHA is a 'superpozzolan' with so great specific surface and with so highly activity.