Al2O3·2SiO2 powders synthesized via sol–gel as pure raw material in geopolymer preparation
Autor: | Piercarlo Mustarelli, Michelina Catauro, Alice S. Cattaneo, Flavia Bollino |
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Přispěvatelé: | Catauro, M, Bollino, F, Cattaneo, A, Mustarelli, P, Catauro, Michelina, Bollino, Flavia, Cattaneo, Alice Silvia, Mustarelli, Piercarlo |
Jazyk: | angličtina |
Rok vydání: | 2017 |
Předmět: |
Materials Chemistry2506 Metals and Alloys
Materials science Ceramics and Composite 02 engineering and technology Raw material powder 010402 general chemistry Geopolymer 01 natural sciences Solid-state NMR law.invention Al Alkali activation law Aluminosilicate Materials Chemistry Calcination Reactivity (chemistry) Composite material Metakaolin Sol-gel Al2O3·2SiO2 powder 021001 nanoscience & nanotechnology ·2SiO 0104 chemical sciences Solid-state nuclear magnetic resonance Chemical engineering Ceramics and Composites Sol–gel method 0210 nano-technology Sol-gel method |
Popis: | Geopolymers are inorganic aluminosilicates mainly proposed as environmentally friendly building materials, which are obtained by alkali activation of natural minerals, calcined clay (e.g., metakaolin) and other aluminosilicate sources. The wide range of chemical and mineralogical compositions of these raw materials influences several properties of the obtained geopolymers. In the present work, pure Al2O3·2SiO2 powders were synthesized via the sol-gel technique and proposed as pure aluminosilicate sources to prepare alkali activated geopolymers. Samples differing in the ratio between the SiO2 precursor and the H2O used in the sol-gel process were prepared, in order to study the effect of water content on the material structure and reactivity. The chemical structure of all the obtained Al2O3·2SiO2 powders were characterized by Fourier transform infrared (FT-IR) and solid-state nuclear magnetic resonance (27Al and 29Si MAS NMR) spectroscopies and compared to that of a reference metakaolin. Moreover, material reactivity was evaluated by alkali activation of the samples. After 28 days of ageing, 27Al and 29Si MAS NMR and FT-IR spectra ascertained the formation of a geopolymeric network in the activated samples. The results showed that lower water content allows obtaining a homogeneous Al-rich geopolymer similar to that obtained, using metakaolin as raw material. |
Databáze: | OpenAIRE |
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