氧化物组分摩尔比对偏高岭土基地聚合物力学性能及结构的影响

Effects of the molar ratio of oxide components on the mechanical properties and structure of metakaolin geopolymer

以偏高岭土、水玻璃和氢氧化钠为主要原料制备地聚合物,研究了氧化物组分摩尔比(n(SiO_2)/n(Al_2O_3)、n(Na2O)/n(Al_2O_3)和n(H2O)/n(Al_2O_3))对偏高岭土基地聚合物抗压强度的影响,采用X射线衍射(XRD)和傅里叶变换红外光谱(FTIR)对地聚合物的结构和组成进行了分析。结果表明,三种摩尔比在一定范围内均存在最佳值,在最佳配比下制得的地聚合物样品3,7,28 d抗压强度分别为62.6,69.4,77.2 MPa。在地聚合反应中,主要形成无定形凝胶结构,当n(SiO_2)/n(Al_2O_3)<3.6和n(Na2O)/n(Al_2O_3)<0.8时,产生结晶度良好的沸石晶体。

Geopolymer was prepared by using metakaolin,sodium silicate and sodium hydroxide as main raw materials. The effects of the molar ratio of oxide components n( SiO_2)/n( Al_2O_3),n( Na_2O)/n( Al_2O_3) and n( H_2 O)/n( Al_2O_3)) on the compressive strength of metakaolin geopolymer were investigated. The structure and components of geopolymers with different molar ratios of the oxide components were analyzed by means of X-ray diffraction( XRD) and Fourier transform infrared( FTIR). The results show that the molar ratio has an optimal value in a certain range. The geopolymer sample prepared with optimum molar ratios could reach the 3,7 d and 28 d compressive strength of 62. 6,69. 4,77. 2 MPa,respectively. During geopolymerization,the resulted products were amorphous phases gel structure,with Si O2/Al_2O_3 molar ratios less than 3. 6 and Na2 O/Al_2O_3 less than 0. 8,the resulted products were zeolite crystals with good crystallinity.