文献类型：期刊文献

英文题名：The influence of calcium source on the preparation of geopolymer using circulating fluidized bed fly ash

作者：Qiao, Xiu-chen[1]

机构：[1] School of Resource and Environmental Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China

年份：2019

卷号：2

外文期刊名：Sustainable Construction Materials and Technologies

收录：EI(收录号：20200608139848)

语种：英文

外文关键词：Inorganic polymers - Sustainable development - Hydrated lime - Silica - Aluminum oxide - Fluidized beds - Zeolites - Alumina - Fluidized bed process - Calcite - Calcium - Fly ash - Calcium carbonate - Fluidized bed combustion - Curing - Sodium compounds

摘要：Circulating fluidized bed（CFB）fly ash contains a high content of calcium and sulfur, which makes it difficult to be used as traditional construction and building materials. However, the chemical compositions and mineral compositions of CFB fly ash showed potential application in the synthesis of geopolymer. A mixture of metakaolin and CaCO3, CaSO4 and Ca(OH)2 was used to investigate the influence of calcium source on the preparation of geopolymer in the SiO2-Al2O3-CaO-Na2O-H2O system. The results showed that the presence of CaCO3 played a catalytic role and accelerated the setting process. The CaCO3-bearing sample showed the highest strength development at early curing age when the CaO/Al2O3 was 0.5, however, showed the highest after long-term curing when the CaO/Al2O3 was 0.1. New phases faujasite and zeolite formed in 90 day cured CaCO3-bearing samples. When the CaO/Al2O3 was higher than 0.3 the CaSO4-bearing sample quick set due to the formation of AFt. When the CaO/Al2O3 was 0.5 the 28 day cured CaSO4-bearing sample showed a strength reduction due to continuous formation of AFt. New phases including thenardite and faujasite formed in CaSO4-bearing sample. The pozzolanic reaction and the geopolymerization reaction were the main reactions in the Ca(OH)2-bearing samples. ? 2019 International Committee of the SCMT conferences. All rights reserved.