利用机械力化学活化粉煤灰制备莫来石

Preparation of mullite using chemical activiation of fly ash by mechanical force

为了探索煤化学工程中粉煤灰的高附加值利用途径,利用机械力化学效应激发粉煤灰的潜在活性。以粉煤灰与Al2O3粉末混合样品(MS)为原料,通过机械粉磨的方式进行处理,并在较低温度条件下煅烧制取莫来石。该方法制备莫来石所需的煅烧温度低(1 150℃),成品纯度高(只含莫来石相和玻璃相,其中莫来石质量分数达到92%)。当机械粉磨时间为30h时,最适宜的煅烧温度为1 150℃,得到纳米莫来石的晶粒大小为35nm。针对不同粉磨时间的样品,DTA和XRD分析均表明:机械粉磨的时间越长,样品晶格结构无序化越强,大大降低了固相反应所需的活化能,提高了MS样品的活性,有利于莫来石在低温条件下析出生成。

To explore the high value added utilization of fly ash,mullite was prepared by means of mechanical grinding and then calcination under the condition of low temperature using fly ash mixed with Al2 O3 powder (MS)as raw material.The calcination temperature for the preparation of mullite by this method is low (1 150 ℃)and the purity of prepared mullite is high (only contai-ning mullite phase and glass phase,wherein the mullite mass fraction is 92%).When the grinding time is 30 h,the best calcina-tion temperature is 1 150 ℃,the formed praticles of nano mullite size is 35 nm.For the the samples by different grinding time, the analysis of DTA and XRD show when the mechanical grinding is longer,the lattice structure disorder of the samples is en-hanced,the activation energy for the solid phase reaction is significantly reduced,the activity of the MS samples is improved,in favor of the formation of mullite under relative low temperature.