Preparation and microstructure analysis of iron tailings/fly ash based geopolymer
To improve the compressive strength of the prepared fly ash/iron tailings based geopolymer(IGF),the effects of n(Na2O)/n(Al2O3),activator modulus,liquid-solid ratio,solidification temperature and iron tailings content on the compressive strength of IGF were analyzed through single factor and orthogonal experiments.The phase changes of IGF were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and infrared spectroscopy(FTIR).The results showed that the compressive strength of IGF increased first and then decreased with the increase of activator modulus,n(Na2O)/n(Al2O3),liquid-solid ratio and iron tailings content,and was positively correlated with the curing temperature.The order of influence was:curing temperature>modulus>liquid-solid ratio>n(Na2O)/n(Al2O3).SEM and XRD results indicated that IGF contained abundant SiO2 and Al2O3.The hydrated calcium silicate(C-A-H gel and C-S-H gel)generated by the combination of the two materials could make the structure more compact,and improve its durability and strength.In addition,adding iron tailings to fly ash based geopolymers could fill the pore structure of IGF,reduce microstructural damage,increase its density,meet the application standards of building materials,and provide possibilities for seeking cement substitutes and improving industry efficiency.
iron tailingsfly ashgeopolymerscompressive strengthamorphous gelorthogonal test
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