利用粉煤灰与铝矾土合成莫来石的研究

Research on synthesizing mullite with fly ash and bauxite

用粉煤灰直接制备M45莫来石以及与铝矾土混合合成M60莫来石,可大大降低莫来石的合成成本。采用综合热分析仪(TG-DSC)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)对样品进行表征。结果表明:经800℃煅烧2 h并经除铁处理的粉煤灰可直接作为低牌号莫来石(M45)使用;用预处理的粉煤灰和铝矾土混合制备高牌号莫来石(M60)适宜的烧结温度为1 000℃;合成的莫来石的主要组分符合中国烧结莫来石标准(YB/T 5267—2005)。

M45 mullite was prepared directly from fly ash and M60 mullite was prepared by mixing fly ash with bauxite. Therefore, the cost of synthesizing mullite was largely reduced. Samples were characterized by thermogravimetry-differential scanning calorimeter （ TG - DSC ） , X - ray diffraction （ XRD ） , and scanning electron microscope （ SEM ）. Results showed that the fly ash sintered at 800℃ for 2 h and disposed by technology of iron removal could be used directly as low grade mullite （ M45 ） , and the profitable sintering temperature was 1 000 ℃for the pretreated fly ash mixed with bauxite in preparing high grade mullite （M60）. Main chemical compositions of the synthesized mullite could meet the Standard of Sintered Mullite of China （ YB/T 5267--2005 ）.