Preparation of low-cost mullite ceramics from natural bauxite and industrial waste fly ash
Preparation of low-cost mullite ceramics from natural bauxite and industrial waste fly ash
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DOI：
10.1016/j.jallcom.2007.06.023
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发表时间：
2008-07
影响因子：
6.2
通讯作者：
Yingchao Dong;Xuyong Feng;Xuefei Feng;Yan-Wei Ding;Xing-qin Liu;G. Meng
中科院分区：
文献类型：
--
作者：
Yingchao Dong;Xuyong Feng;Xuefei Feng;Yan-Wei Ding;Xing-qin Liu;G. Meng
以天然高铝矾土和工业废渣粉煤灰为原料，制备了低成本莫来石陶瓷。采用X射线衍射仪对粉煤灰、铝土矿及其莫来石组成为3：2的混合物的烧成样品进行了表征。结果表明，在1300°C以下，方石英与Al2O3发生固相反应，随后Al2O3溶解成过渡玻璃相，发生二次莫来石化。结果表明，二次莫来石的形成导致了轻微的膨胀，尽管烧结引起的收缩。此外，样品在高温下烧制，然后在相对密度、孔隙率、微观结构和断裂强度方面进行表征。在1600°C时，相对密度和断裂强度分别为93.94%和186.19MPa。在烧结体中仅观察到少量的近球形闭合孔。
Low-cost mullite ceramics were prepared from the mixtures of natural bauxite and industrial waste fly ash. The fired samples, including fly ash, bauxite and their mixture based on the composition of 3:2 mullite, were characterized respectively by XRD (X-ray diffraction). The results indicate that the secondary mullitization occurred by the solid-state reaction of cristobalite and corundum below 1300°C, followed by the dissolution of corundum into transitory glassy phase at higher temperatures. The dilatometric results reveal that the formation of secondary mullite resulted in a slight expansion in spite of the shrinkage induced by sintering. In addition, the samples were fired at elevated temperatures and then characterized in terms of relative density, porosity, micro-structure and fracture strength. At 1600°C, the relative density and fracture strength are 93.94% and 186.19MPa, respectively. Only a small amount of nearly spherical closed pores were observed in the sintered body.