循环流化床灰渣制备胶凝材料综述

Review on Preparation of Cementitious Materials from Circulating Fluidized Bed Combustion Ash

循环流化床(Circulating Fluidized Bed,CFB)灰渣是一种全新的燃煤固废,为了促进其在胶凝材料领域的应用,本文综述了不同CFB灰渣制备胶凝材料的方法和制约条件。文献研究显示,较高的火山灰活性和水硬性让CFB灰渣常被用作辅助胶凝材料,但体系SO_(3)质量分数常控制为小于3.5%。当CFB灰渣掺量不超过20%时,可与粉煤灰、矿粉等复配制备生态水泥。用CFB灰渣制备蒸压加气混凝土时,当体系SO_(3)质量分数超过5.0%时,产品中托贝莫来石生成量下降、吸湿特性增强。低硫低钙CFB灰渣可制备地质聚合物,但体系总CaO超过3.5%,地聚反应减少、水化反应增多。CFB灰渣无论新陈,均可以用来制备可控低强度材料。此外,本文也指出了针对CFB灰渣的理论和应用研究方向。

Circulating fluidized bed(CFB)combustion ash is a totally new solid waste discarded from coal combustion process.In order to accelerate the investigation and utilization of CFB ash,this paper summarizes the utilization methods and constraints of CFB ash in the preparation of cementitious materials.The literature review shows that CFB ash shows high pozzolanic and hydraulic properties and is hence always used as sup-plementary cementitious materials,however,the mass fraction SO_(3) in the system is generally lower than 3.5%.CFB ash is suitable for the prepara-tion of an eco-cement when mixing with coal fly ash or granulated blast furnace slag when its mixing percentage is lower than 20%.When it is used for the preparation of autoclaved aerated concrete,the amount of tobermorite in sample decreases and the moisture adsorption capacity of product increases when the amount of mass fraction SO_(3) is higher than 5.0%.CFB ash with low CaO and SO_(3) is a good raw material for the preparation of geopolymer.However,geopolymerizationg decreases and hydration increases when the amount of total CaO is higher than 3.5%.Both fresh and hy-drated CFB ash are all good for the preparation of controlled low strength materials.Some research suggestions are also presented on the theoretical and applied research.