铁尾矿—偏高岭土基地聚物配方优化及机理

Formula Optimization and Mechanism of Preparing Geopolymers Based on Iron Tailings and Metakaolin

以铁尾矿为主要原料,并添加偏高岭土作为校正材料,以NaOH溶液和水玻璃作为碱激发剂制备地聚物,通过正交试验研究原料配比对地聚物性能的影响。研究结果表明,在原料n(SiO_2):n(Al_2O_3)为3.0、液固比0.35、碱激发剂模数1.2的条件下,所制得试样28 d的抗压强度最大,为59.0 MPa。采用X射线衍射分析(XRD)、傅里叶红外光谱仪分析(FTIR)和扫描电子显微镜分析(SEM)对最佳条件制备的试样微观结构进行表征表明,试样具有地聚物的微观结构特征,主要物相组成为无定形的硅铝酸盐、半结晶的CSH(I)和α-C_2SH,随着龄期的增长,生成了更多凝胶状物质将细颗粒物胶结在一起,导致试样结构密实,抗压强度提高。

Geopolymers were prepared with the iron tailings as main raw materials, metakaolin as the adjusted materials, with NaOH solution and sodium silicate as alkali activator agent, the effects of raw materials ratio on the properties of geopolymers were investigated by orthogonal testThe results show that under the conditions of raw materials with n(SiO2):n(Al2O3) of 3.0, liquid-solid ratio of 0.35, and alkali activator modulus of 1.2, the compressive strength value of geopolymers is the highest at 28 d, which comes up to 59.0 MPa. The microstructure of the samples were characterized by XRD, FTIR and SEM. Microscopic analysis indicate that the samples have the microstructure characteristics of the normal geopolymers, and the main compositions are amorphous aluminosilicate, semi-crystalline CSH(I) and α-C2SH. As the curing ages are prolonged, more gelatinous substances are generated and bond the fine particles together to form compact internal structure in samples, which improves the compressive strength of geopolymers.