固硫灰渣的微观结构与火山灰反应特性

MICROSTRUCTURE AND POZZOLANIC REACTIVITY OF FLUIDIZED BED COMBUSTION ASHES

用X射线衍射、红外光谱和扫描电镜研究流化床燃煤固硫灰渣(简称固硫灰渣)的微观结构。用化学反应动力学方法研究固硫灰渣的火山灰反应特性,并与粉煤灰进行对比。阐述了固硫灰渣的微观结构与其火山灰反应特性之间的关系。结果表明:固硫灰渣与粉煤灰矿物组成差异较大,主要体现在它不含莫来石。固硫灰渣中[SiO4]和[AlO6]聚合度均低于粉煤灰的。固硫灰渣颗粒表面比粉煤灰的疏松。固硫灰渣的火山灰反应速率常数明显高于粉煤灰的,而表观活化能相反。固硫灰渣火山灰反应活性明显高于粉煤灰的,反应阻力也较小,这是由其微观结构所决定的。

Microstructures of fluidized bed combustion （FBC） ashes and pulverized coal （PC） ashes were measured by X-ray diffraction, infrared spectroscopy and scanning electron microscope. The pozzolanic reactivity of FBC and PC ashes was investigated based on the kinetics of the pozzolanic reaction. The relationship between the microstructures and the pozzolanic reactivity of the FBC ashes was thoroughly researched. The results show that the FBC ashes have some characterizations that are very different from PC ashes; for example, they contain no mullite, and have a lower polymerization degree of [SiO4] and [AlO6] and looser texture. The reaction rate constant of the FBC ashes is higher than that of the PC ashes, while the activation energy is just the opposite. The pozzolanic activity of the FBC ashes is significantly higher than that of the PC ashes, and the reaction barrier of the former is lower than that of the latter, which are controlled by their microstructures.