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为了实现农作物稻秸的多层分级利用,采用扫描电子显微镜和X-射线能谱分析仪分析硅在稻秸单元表面的存在形式和分布形态,并进一步利用稻秸制备成微纳米二氧化硅,探讨热解温度(575、675、775℃)和热解时间(2、4h)对二氧化硅得率和粒径的影响。研究表明,硅主要以二氧化硅的形式存在于稻秸表面的颗粒物区,质量分数达12.8%。热机械处理可以减小硅的粒径。在相同的热解温度下,热解时间从2h增加到4h,二氧化硅颗粒粒径逐渐增大,并且使纳米二氧化硅得率保持在8%以上。。在相同的热解时间下,热解温度上升使得二氧化硅粒径变大。球磨处理可以改善二氧化硅颗粒的团聚现象,并且使粒径从18.94μm下降到6μm以下,处于小于100nm的比例增多。研究结果为以稻秸为原料制备纳米二氧化硅提供参考。
In order to achieve multi-level grading of crop straw, the existence form and distribution of silicon on rice straw unit surface were analyzed by scanning electron microscopy and X-ray energy dispersive spectroscopy, and the micro-nano silica was further prepared by using rice straw. Effects of pyrolysis temperature (575, 675, 775 ℃) and pyrolysis time (2, 4h) on yield and particle size of silica were investigated. The results show that silicon is mainly present in the form of silica in the particulate matter on the surface of rice straw, with a mass fraction of 12.8%. Thermomechanical treatment can reduce the particle size of silicon. At the same pyrolysis temperature, the pyrolysis time increased from 2h to 4h, the particle size of silica particles increased gradually, and the yield of nano-silica was kept above 8%. . At the same pyrolysis time, the pyrolysis temperature increases so that the silica particle size becomes larger. Ball milling can improve the agglomeration of silica particles and decrease the particle size from 18.94μm to 6μm or less, and the proportion of less than 100nm increases. The results provide a reference for the preparation of nanosilica from rice straw.