Alkaline activation of metakaolin–fly ash mixtures: Obtain of Zeoceramics and Zeocements

This study examines the variation in physico-mechanical properties and mineralogical and microstructural characteristics of the alkaline inorganic polymers obtained by alkaline activation, with a mixture of sodium silica solution and sodium hydroxide, of two different starting materials: matrix M (metakaolin) and matrix FM (50% fly ash and 50% metakaolin). The activation process was conducted at different temperatures (85 °C, 150 °C, and 200 °C). The highest strength values were obtained for the FM matrix at 150 °C. The main reaction product was a sodium aluminosilicate gel in every case. Zeolites formed as by-products. The quantity and type of arising zeolites (sodalite, zeolite A, and faujasite) depended on the nature of the starting material and on the curing conditions used.The authors would like to thank the Programme for High Specialisation in Industrial Technologies “New low-temperature techniques and ceramic coverings” funded by the Instituto de la Pequeña y Mediana Industria de la Generalitat Valenciana, IMPIVA (REF. IMAETA/2004/15 – IMAETB/2005/12). Thanks are also due to the Directorate General of Scientific Research for financing project BIA2004-04835; and to the CSIC for co-financing European social contract REF. I3P-PC2004L.Peer reviewe

Alkaline activation of metakaolin–fly ash mixtures: Obtain of Zeoceramics and Zeocements

This study examines the variation in physico-mechanical properties and mineralogical and microstructural characteristics of the alkaline inorganic polymers obtained by alkaline activation, with a mixture of sodium silica solution and sodium hydroxide, of two different starting materials: matrix M (metakaolin) and matrix FM (50% fly ash and 50% metakaolin). The activation process was conducted at different temperatures (85 °C, 150 °C, and 200 °C). The highest strength values were obtained for the FM matrix at 150 °C. The main reaction product was a sodium aluminosilicate gel in every case. Zeolites formed as by-products. The quantity and type of arising zeolites (sodalite, zeolite A, and faujasite) depended on the nature of the starting material and on the curing conditions used