激发剂含量与原料比对地质聚合物显微结构与性能的影响

Effect of Activator Content and Raw Material Ratio on Microstructure and Properties of Geopolymer

采用压制成型法制备了粉煤灰基地质聚合物,采用XRD与SEM-EDS测试手段研究了激发剂含量与原料质量比对地质聚合物样品显微结构与抗折强度的影响。结果表明:激发剂的质量百分比为23 wt.%时,抗折强度最大值为35.84 MPa;Na型针沸石发育程度较好,呈“芽刺状”;硅铝摩尔比为1.37,但样品的泛碱程度较大。粉煤灰与炉渣的比例对地质聚合物抗折强度的影响规律分为两段:当粉煤灰添加量小于80%时,样品的抗折强度呈递增规律,符合方程y=0.211x+19.117;当粉煤灰添加量大于80%时,样品的抗折强度呈先增后减的规律,符合方程y=0.041x^(2)-7.572x+379.617。两种原料比例为80∶20时,Na型针沸石相特征峰强度达到最大,形貌呈细直状或弯曲状,发育较佳,相互之间穿插在缝隙之中,样品抗折强度最大,近似为双硅铝链结构产物。

Fly ash based geopolymer was prepared by pressing molding method.Effect of activator content and fly ash to slag ratio on the microstructure and bending strength of geopolymers were studied by XRD,SEM and EDS.The results show that the maximum bending strength is 35.84 MPa when the activator content is 23 wt.%.Na-type zeolite phase is well developed and the morphologies appears as bud thorn with Si/Al mole ratio of 1.37 with high efflorescence degree.Influence of fly ash to slag ratio on the bending strengths of geopolymers can be divided into two sections.The bending strengths of the samples basically present an increasing trend when the fly ash contents are less than 80%and are closely consonant with the equation of y=0.211x+19.117;The bending strengths of the samples assume parabola relation when the fly ash contents are more than 80%and are are closely consonant with the equation of y=0.041x^(2)–7.572x+379.617.Na-type needle zeolite phase and trona phase appear in the microstructure of the samples.When the ratio of the two raw materials is 80:20,the intensity of the diffraction peak representing Na-type zeolite phase has the maximum value.The growth of the zeolite phase is well with the crystal morphologies of fine straight or curved filament and intersperse between each other in the microstructure.The bending strength of the sample is maximum with a double chain structure of Si-O-Al formed.