Preparation of nano-sized Al2O3–2SiO2 powder by sol–gel plus azeotropic distillation method

Nano-sized amorphous Al2O3–2SiO2 powder was prepared by a sol–gel method coupled with azeotropic distillation. The structure of the powder was investigated by DTS, BET, TEM, FT-IR, TG-DTA and XRD, showing that n-butanol azeotropic distillation could effectively remove water from the aluminosilicate gels and prevent the formation of hard agglomerates in the drying process. The average particle diameter of the powder was about 70 nm. The largest BET specific surface area of the powder was 669 m2/g. To examine the alkali-activation reactivity of the powder, alkali-activation tests were performed with the powder reacting with sodium silicate solution. The synthetic powder was found to be highly reactive.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Nano-sized Al2O3–2SiO2 powder was prepared by a sol–gel method with azeotropic distillation. ► The azeotropic distillation could effectively prevent formation of hard agglomerates. ► The synthetic powder possesses high alkali-activation reactivity.