燃煤固体产物的矿物组成研究

A STUDY OF THE MINERAL COMPOSITION OF COAL COMBUSTION RESIDUES

利用X射线衍射、穆斯堡尔谱与扫描电子显微镜等方法研究中国典型燃煤煤种的燃烧产物的矿物学特征 ,揭示出不同化学成分以及不同类型产物中矿物组成的差异性。根据化学成分 ,可将燃煤固体产物分为硅铝质、铁质和钙质三组 ,硅铝质产物的结晶相主要为莫来石和石英 ,而结渣中基本为莫来石 ;铁质产物中主要矿物包括α Fe2 O3 、γ Fe2 O3 与Fe3 O4 ,其含量随锅炉燃烧温度的变化而变化 ;钙质产物中矿物种类复杂 ,飞灰中检出石灰、石膏和石英 ,沾污中检出石膏、赤铁矿和石英 ,而结渣中还发现钙的硅酸盐矿物。上述矿物分布特征是由不同成分的硅酸盐熔体在不同热力学条件下的结晶行为所决定的。

The mineral composition of typical coal combustion residues in China, including fly ash, bottom ash, slagging and fouling, were investigated by X\|ray diffraction, Mssbauer spectroscopy and scanning electron microscopy. According to the chemical composition, coal combustion residues can be divided into aluminosilicate, ferruginous and calcareous groups. The mineral phase in aluminosilicate residues is composed mainly of mullite and quartz, but only mullite is detected in aluminosilicate slagging. The mineral association of ferruginous residues consists of α\|Fe\-2O\-3, γ\|Fe\-2O\-3 and Fe\-3O\-4, and their contents vary with the combustion temperature of the boiler. The mineral composition of calcareous group is quite different from one type to another type of residues, the fly ash mainly consists of lime , gypsum and quartz; the fouling mainly consists of gypsum , hematite and quartz; and the slagging consists mainly of portlandite, magnetite and quartz . These mineral associations are depend upon the crystallization behavior of silicate melts differing in chemical composition under different thermodynamic conditions.