煤矸石基地质聚合物的制备及微观结构

Preparation and microstructure of coal gangue-based geopolymer

采用正交试验分析了球磨时间、碱溶液模数、固含量以及液固质量比(简称液固比)对煤矸石基地质聚合物单轴抗压强度和弹性模量的影响,结合扫描电子显微镜(SEM)、X射线衍射(XRD)、红外光谱(FTIR)和核磁共振(NMR)对煤矸石基地质聚合物进行了表征,探讨了不同力学性能煤矸石基地质聚合物的微观结构差异.结果表明:煤矸石基地质聚合物的抗压强度和弹性模量随碱溶液模数和液固比增加而减小,随固含量增加先增大后减小,其中固含量影响最显著,液固比和模数影响较显著,球磨时间影响最小.SEM结果显示抗压强度高的地质聚合物微观表面结构致密,观察不到明显的煤矸石颗粒轮廓,说明地质聚合反应较充分.XRD结果显示地质聚合物中晶相结构单一,主要为石英结构.地质聚合物抗压强度越大,波数1200~950 cm^(-1)范围内的Si(Al)-O结构越多.化学位移56.36×10^(-6)~57.51×10^(-6)范围的AlQ_(4)(4Si)型^(27)Al NMR窄谱峰和化学位移-93.18×10^(-6)~-88.66×10^(-6)范围的Q^(4)(3Al)型^(29)Si NMR宽漫峰,表征了煤矸石基地质聚合物的生成以及地质聚合反应程度的强弱.

The orthogonal experimental was used to study the influence of milling time,modulus of alkali solution,solid content and liquid-solid ratio on uniaxial compressive strength and elastic modulus of coal gangue-based geopolymer(CGGP).The microstructure difference of CGGP with different mechanical properties were characterized by scanning electron microscope(SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and nuclear magnetic resonance(NMR).The results show that the uniaxial compressive strength and elastic modulus decrease with the increase of alkali solution modulus and liquid-solid ratio,but firstly increase and then decrease with the increase of solid content.The effect of solid content is the most significant,liquid-solid ratio and modulus are more significant,and ball milling time is the least.The SEM results show that the CGGP with higher uniaxial compressive strength have denser and smoother micro-physical surface without obvious coal gangue particle outline,indicating that the geopolymerization reaction is sufficient.The XRD spectra results show that the crystalline phase structure of CGGP is single,mainly quartz.The higher uniaxial compressive strength of CGGP have more Si(Al)—O structural types in wavenumber 1200—950 cm^(-1)of FTIR spectra.The formation of CGGP can be characterized by the appearance of^(27)Al NMR narrow peak between chemical shift of 56.36×10^(-6)—57.51×10^(-6)(AlQ^(4)(4 Si))and^(29)Si NMR wide peak at between-93.18×10^(-6)—-88.66×10^(-6)(Q_(4)(3 Al)).