高铝粉煤灰制备莫来石晶须的实验研究

MULLITE WHISKERS DERIVED FROM HIGH-ALUMINIUM COAL FLY ASH

以高铝粉煤灰、NH4Al(SO4)2.12H2O和NaH2PO4.2H2O等为原料,设计配方研究温度对莫来石晶须生长的影响。运用X射线粉末衍射(XRD)和扫描电子显微镜(SEM)等手段,对莫来石及晶须形成过程进行表征,结果表明:当Al2O3/SiO2摩尔比为0.32,烧结温度1 400℃,保温时间6 h,可获得直径为0.2 mm^0.5 mm,长径比为17~30的莫来石晶须。

Mullite whiskers have been successfully synthesized from starting materials of high-aluminium coal fly ash,NH4Al（SO4）2·12H2O and SiO2,with a small addition of NaH2PO4·2H2O by designing composition sintered at different temperatures in air for 6 h.The formation mechanism,morphology,composition and structure of the mullite whisker were investigated by XRD,EDS and SEM respectively.Results showed that the mullite micro-crystal began growing at 1 200 ℃,and grew into the whisker at 1 400 ℃.Mullite whiskers with a diameter of 0.2 mm～0.5 mm（aspect ratio 17～30） have been manufactured at 1 400 ℃ for 6h with the Al2O3/SiO2 molar ratio of 0.32 after chemically leaching the glass matrix with HF solution.