铁尾矿-矿渣基地聚合物的制备及其性能

Preparation and properties of iron tailing - slag based geopolymer

我国铁尾矿产生量较高,但利用率仍较低,为了高附加值资源化利用铁尾矿,将铁尾矿、高炉矿渣与粉煤灰混合后作为硅铝原料,通过机械粉磨和碱性激发剂来激发其反应活性,制备地聚合物胶凝材料。探讨了高炉矿渣与铁尾矿的配比、碱激发剂水玻璃的掺量对地聚合物试样抗压强度的影响,分析了地聚合物胶凝材料形成机理。结果表明:将铁尾矿和高炉矿渣采用机械粉磨活化时,粉磨时间超过60 min后其比表面积提高幅度变小,综合考虑原料活性和成本,机械粉磨时间定为60 min。当粉煤灰掺量为10%、高炉矿渣与铁尾矿的配比为5∶3、碱性激发剂水玻璃掺量为10%时,所制得的地聚合物试样3、7、28 d龄期的抗压强度分别为10.7、18.9、32.9 MPa。地聚合物试样在养护过程中,随着养护时间的延长,试样的结构越来越致密,尤其是28 d龄期的试样结构更加致密,生成的凝胶产物填充在原料颗粒之间的空隙,并将未反应的原料颗粒包裹,与相邻的凝胶产物相互胶结,形成一整体,从而有利于试样抗压强度的提高。

The production of iron tailing in China is abundant,but the utilization rate is still low.In order to achieve the high value-added utilization of the iron tailing,the geopolymer cementitious materials were prepared by iron tailing,blast furnace slag and fly ash as the aluminosilicate raw materials,which were activated by mechanical grinding and alkali activators.The effects of blast furnace slag to iron tailings ratio and the content of water glass activators on the compressive strength of the geopolymer samples were studied.Additionally,the formation mechanism of geopolymer cementitious materials was analyzed.The results show that the iron tailing and blast furnace slag are activated by mechanical grinding,and the increase in specific surface area slows down after 60 minutes of grinding.Considering the activity of raw materials and cost,the optimal mechanical grinding time is 60 min.With a fly ash content of 10%,a blast furnace slag to iron tailings ratio of 5∶3,and a water glass content of 10%,the compressive strength of the geopolymer samples at 3 d,7 d and 28 d reaches 10.7 MPa、18.9 MPa and 32.9 MPa,respectively.During the curing process of the geopolymer samples,as the curing time increases,the structure of the samples becomes denser and denser.The structure of the 28 d sample is more compact,the gaps between the raw material particles are filled by the generated gel products,and the unreacted raw material particles are wrapped by the generated gel products,which bond with the adjacent gel products to form a whole.The compact structure is beneficial in improving the compressive strength of the samples.