The use of activated alkali aluminosilicate has been shown to be an economically-viable alternative that decreases the environmental impact of building construction material. Geopolymers are a type of activated alkali aluminosilicate that are rich in SiO2 and Al2O3, and harden within alkaline solutions. In this study, geopolymers obtained by alkaline activation of metakaolin with high iron content were characterized. The activation process used sodium hydroxide solutions at molarities of 12, 15, and 18 mol. The geopolymers were oven-dried at 85°C and at room temperature. The results identified the physicochemical and microstructural properties of the geopolymers and elucidated the activation process using the techniques: XRF, XRD, DTA, TG, DTG and DSC analysis. The results of the dynamic recrystallization indicated the presence of quartz, kaolinite, hematite, and muscovite in the samples. The DSC analyses showed an immediate reaction between the precursor material and the activator. The DTA results showed that the reactions began at low temperatures, where the dissolution of Si and Al occurred. The peaks that appear between 45°C and 60°C indicate that polymerization occurred through the condensation of Si and Al.
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