材料期刊网

以偏高岭土掺加石灰石和石膏模拟循环流化床(CFB)飞灰,研究了不同SiO2/Al2O3和Na2O/Al2O3对烧粘土材料合成地聚物过程中,凝结时间和抗压强度的变化规律;借助X射线衍射和拉曼图谱分析,证明了CFB合成地聚物过程中存在10种主要化学反应.同时发现:碱激发剂中钠含量变化主要影响活性硅、铝单体数量的多少,活性硅含量增加更有利于生成CSH和(Na,Ca)-PSS型地聚物;在SiO2-Al2O3-CaO-Na2O体系中,当Na2O/Al2O3≥1.1时,反应体系因生成水化石榴石而改变地聚反应历程,进而对样品抗压强度产生负效应;SiO2/Al2O3≥3.0时,样品凝结迅速,不利搅拌.

The mixture of metakaolin and calcite or gypsum instead of circulating fluidized bed (CFB) fly ash was used to investigate the influence of SiO2/Al2O3 and Na2O/Al2O3 on the setting time and compressive strength of geopolymer.The results of X-ray diffraction (XRD) and Raman spectrum proved that there are 10 chemical reactions occurred in the preparation of metakaolin-based geopolymer.The experimental results also showed that: the variation of sodium components in alkali activator controlled the amount of complex silicon or aluminum anion group, and the formation of CSH and (Na, Ca)-PSS depended on the amount of complex silicon anion group.In the SiO2-Al2O3-CaO-Na2O system, the formation of hydrogarnet showed negative effect on the strength development of geopolymer when Na2O/Al2O3≥1.1, and the geopolymer product set too fast to mix properly when SiO2/Al2O3≥3.0.