激发剂的性质对页岩提钒尾渣基地聚物性能的影响

Effects of Properties of Activators on Compressive Strength of Shale Vanadium Tailings Based Geopolymer

为研究地聚物的弱碱性激发技术,以湖北某地的页岩提钒尾渣为原料,进行了地聚物碱激发研究。主要研究了不同偏高岭土掺量、激发剂模数和激发剂用量对地聚物抗压强度的影响。最终确定在m(提钒尾渣)∶m(偏高岭土)=9∶1,弱碱性激发剂Na2SiO3的模数为3. 0,Na2SiO3的掺量为14%的激发制度下,地聚物试样3 d的抗压强度即可达到27. 55 MPa,极大地提高了地聚物的抗压性能。对不同模数的硅酸钠下制备的地聚物进行物相转变、化学键变化和微观形貌分析,发现在液体硅酸钠的作用下,页岩提钒尾渣中的石英被进一步溶解;溶解的无定形硅铝物质与液体硅酸钠中的硅酸根反应逐渐生成硅铝凝胶相;液体硅酸钠中的硅酸根起一个诱导作用,液体硅酸钠的模数越高,其硅酸根含量越高,与页岩提钒尾渣中的无定形硅铝物质反应也越迅速,从而生成更多的硅铝凝胶相,促进了地聚物抗压强度的提高,实现了地聚物的安全制备。

In order to study the weak alkaline activation technology of geopolymer,alkali activation of geopolymer was studied using the shale vanadium tailings in Hubei Province as raw materials.The effects of different addition of metakaolin,modulus of activator and dosage of activator on the compressive strength of geopolymer were studied. Finally,the compressive strength of the geopolymer sample can reach 27. 55 MPa in 3 days under the activation system of m( shale vanadium tailings) ∶m( metakaolin) is 9 ∶1,the modulus of weak alkaline activator Na2SiO3 is 3. 0 and the dosage of activator is 14%,which greatly improves the compressive performance of the geopolymer.The phase transition,chemical bond change and micro-morphology of the geopolymers prepared under different modulus sodium silicate were analyzed. It was found that the quartz in the vanadium tailings is further dissolved under the action of liquid sodium silicate. The dissolved amorphous silicon and aluminum compounds react with silicates in liquid sodium silicate to form silica-alumina gel phases. Silicates in the liquid sodium silicate acts as an inducer,the higher the modulus of the liquid sodium silicate is,the higher the content of silicates is,and the faster the reaction between the liquid sodium silicate and amorphous silicon and aluminum compounds in vanadium tailings is.Thus,more silica-alumina gel phases are formed and the compressive strength of geopolymer is improved,and the safe preparation of geopolymer has been realized.