Geopolymerization of halloysite via alkali-activation: Dependence of microstructures on precalcination
Geopolymerization of halloysite via alkali-activation: Dependence of microstructures on precalcination
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通过碱活化进行埃洛石的地质聚合：微观结构对预分解的依赖性
DOI：
10.1016/j.clay.2019.105375
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发表时间：
2020-02
影响因子：
5.6
通讯作者：
Liu Dong
中科院分区：
文献类型：
--
作者：
Zhang Baifa;Guo Haozhe;Yuan Peng;Li Yun;Wang Qiang;Deng Liangliang;Liu Dong
埃洛石具有与高岭石非常相似的化学组成，但它具有特殊的纳米管结构和表面反应性。本文研究了埃洛石的碱活化地质聚合反应，研究了450 °C ~ 1000 °C预煅烧温度对埃洛石基地质聚合物微观结构和力学性能的影响。所得产物的特征在于使用组合的技术，包括X-射线衍射，傅里叶变换红外光谱，扫描电子显微镜，N2物理吸附分析，和核磁共振。结果表明，埃洛石在450 °C煅烧时结构变化最小，其碱活化产物由于形成多孔结构的水方钠石而表现出较差的力学性能。在650 °C和850 °C之间的煅烧温度下发生的脱羟基可以改善埃洛石与碱性溶液的反应性。具有致密结构的地质聚合物的形成导致抗压强度增加。当埃洛石在1000 °C下煅烧时，也发生地质聚合，但程度较低，因为形成纳米γ-Al 2 O3。这导致产品的抗压强度降低。这些结果表明，埃洛石基地质聚合物的微观结构和性能在很大程度上取决于埃洛石的预煅烧，并且最佳温度为750 °C左右，以确保具有高反应性的高脱羟基度，这有利于地质聚合。
Halloysite has a chemical composition very similar to that of kaolinite, but it possesses a special nanotubular structure and surface reactivity. This work focuses on the geopolymerization of halloysite via alkali-activation, and investigates the effects of precalcination temperatures ranging from 450 °C to 1000 °C on the microstructures and mechanical properties of halloysite-based geopolymer. The products obtained were characterized using a combination of techniques including X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, N2physisorption analysis, and nuclear magnetic resonance. The results show that halloysite underwent minimal structural changes when calcined at 450 °C, and its alkali-activation product showed poor mechanical properties due to the formation of hydrosodalite with a porous structure. The dehydroxylation that occurred at calcination temperatures between 650 °C and 850 °C could improve the reactivity of halloysite with alkaline solution. The formation of geopolymer with a compact structure resulted in increased compressive strength. When halloysite was calcined at 1000 °C, geopolymerization also occurred, but to a lesser extent because of the formation of nanosized γ-Al2O3. This resulted in a decreased compressive strength in the product. These results indicate that the microstructures and properties of halloysite-based geopolymers are greatly dependent upon the precalcination of halloysite and that the optimal temperature is around 750 °C to ensure a high degree of dehydroxylation with high reactivity, which is favorable for geopolymerization.
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影响因子：
3.5
作者：
K. Heide;M. Földvári
通讯作者：
K. Heide;M. Földvári
DOI：
10.1007/s11595-009-1132-6
发表时间：
2009-03
期刊：
Journal of Wuhan University of Technology-Mater. Sci. Ed.
影响因子：
--
作者：
Zuhua Zhang;X. Yao;Huajun Zhu;Sudong Hua;Yue Chen
通讯作者：
Zuhua Zhang;X. Yao;Huajun Zhu;Sudong Hua;Yue Chen
影响因子：
3.9
作者：
Lee, WKW;van Deventer, JSJ
通讯作者：
van Deventer, JSJ
影响因子：
3.9
作者：
Chen, Xu;Sutrisno, Andre;Struble, Leslie J.
通讯作者：
Struble, Leslie J.
影响因子：
2.2
作者：
P. Yuan;Daoyong Tan;F. Annabi-Bergaya;Wenchang Yan;Mingde Fan;Dong Liu;Hongping He
通讯作者：
P. Yuan;Daoyong Tan;F. Annabi-Bergaya;Wenchang Yan;Mingde Fan;Dong Liu;Hongping He