Effect of the Ratio SiO2/Al2O3 on the Structure, Properties, and Thermal Stability of Geopolymer Refractory Materials

The properties of lightweight geopolymer materials (GM) based on refractory technogenic aluminosilicate wastes were studied. The effect of the ratio of the oxides SiO2 and Al2O3 in the compositions of GM on the physical and mechanical properties of GM was investigated. It was found that SiO2/Al2O3 reduction in the GM composition results in higher density and strength and lower water absorption of the samples after a keeping period. After firing at temperatures 800 and 1000°C the strength of the samples becomes all the higher the lower the ratio SiO2/Al2O3 in the composition. The heat resistance of the samples comprises four thermal cycles for high and more than seven cycles low ratio SiO2/Al2O3.