中文摘要：

为了去除稻壳炭中对水泥基材料有害的残留炭,分别采用通风煅烧和化学沉淀的方法得到稻壳灰 （RHA）和纳米SiO2;采用红外、X射线衍射、扫描/透射电子显微镜和氮吸附-脱附研究了2种产物的结构 和形貌.结果表明： RHA和纳米 SiO2均为无定形结构,残留炭已基本去除;它们呈多孔结构,比表面积分别为179.19和248.67m^2/g;RHA微米级颗粒是由50-100 nm的SiO2凝胶粒子疏松聚集而成;纳米SiO2平均粒径为30nm,分散良好;RHA和纳米 Si02可显著降低饱和氢氧化钙溶液的电导率,增强水泥基复合材 料的早期强度,显示出较高的火山灰活性,可作为生态纳米矿物掺和料.

英文摘要：

The rice husk ash （ RHA） and silica （ Si02） nanoparticles are prepared from rice husk charcoal （RHC） by the methods of ventilated calcining and chemical precipitation, respectively, to remove the residual carbon which is harmful to cement composites. The structures and morphologies of these products are investigated by the Fourier transform infrared spectroscopy, X-ray diffraction, scanning/ transmission electron microscopy and N2 adsorption- desorption analyzer. The results show that the as-produced RHA and Si02 nanoparticles exist in amorphous phase without residual carbon, and exhibit porous structures with specific surface areas of 170.19 and 248. 67 m2 /g , respectively. The micro particles of RHA are aggregated by numerous loosely packed Si02 gel particles with the diameter of 50 to 100 nm. The Si02 nanoparticles are well dispersed with the average size of about 30 nm. Both the RHA and Si02 nanoparticles can significantly reduce the conductivity of saturated Ca（OH）2 solution and increase the early strength of the cement composites. They also exhibit high pozzolanic activity, indicating that they can be used as ecological nano mineral admixtures.