燃烧法所得含纳米氧化铁粉煤灰建筑吸波材料

Fly ash with ferric oxide nanoparticles prepared by combustion method as a building electromagnetic wave absorber

为促进纳米材料的推广应用,研究了量大面广的燃煤工业副产物粉煤灰生产工艺对材料性质的影响,利用扫描电镜、能谱仪、X射线衍射仪等对高铁粉煤灰颗粒微观形貌与性质进行了分析.研究表明:在煤粉燃烧过程中,粘土、石英矿物形成硅酸盐玻璃微珠,矿物中的大部分铁元素在球形玻璃体颗粒表面析晶形成铁氧化物,以二价和三价氧化铁的形式存在,晶粒尺寸为纳米级,且能由还原工艺改性;纳米Fe3O4粒子晶相的存在,使高铁粉煤灰颗粒具有特殊的磁性质以及电磁特性,并成为水泥基材料的电磁波有效吸波剂.因此,粉煤灰的燃烧工艺过程对于纳米材料的制备具有参考价值.

Fly ash,a by-prodcuct of coal-fired industry,has a large number and wide variety sources.And the preparation of fly ash is similar to nanopaticles according to the combustion method.The micro-morphology and characters of the high-iron fly ash were studied.The results show that the clay,quartz and silicate minerals change into silicate glass beads,and most of the iron in the minerals turns into iron oxide by crystallization on the surface of spherical particles during the coal combustion process.The crystal with size of nano-scale is divalent or trivalent iron oxide,and can be modified by deoxidization also.The presence of crystalline nanoFe3 O4 phase leads to a special magnetic and electromagnetic properties in the high-iron fly ash.Therefore the fly ash can be used as a electromagnetic wave absorber in cement-based composites.It comes to the conclusion that the combustion processes of fly ash is worthy to be noticed for the nano-material preparation.