高温弱还原气氛下煤灰中矿物质的定量研究

利用X射线衍射(XRD)研究了1 100-1 500℃条件下弱还原性气氛下胜利褐煤和高平无烟煤煤灰中矿物质的变化,利用Siroquant定量软件计算了高温灰样中矿物质和无定形相的含量,结合化学成分分析,利用差减法计算了煤灰中无定形相的化学组成。结果表明,利用XRD、Siroquant软件并结合化学成分分析,可以对煤灰中的矿物质及无定形相进行定量分析,并可获得不同温度下无定形相的化学组成变化。不同温度范围内煤灰中无定形相的形态不同,当温度低于1 100℃时,煤灰中无定形相主要是未结晶或结晶度较差的氧化物,而随着温度的升高,矿物质发生熔融并形成了玻璃态物质,此时的无定形相则是以熔融的硅酸盐和硅铝酸盐为主。煤灰的硅铝比越低,高温下越容易生成莫来石。

Quantitative analysis of mineral matters in coal ash under reducing atmosphere at high temperature

The behaviors of mineral matters in Shengli and Gaoping coal ash under reducing atmosphere at high temperatures were investigated by X-ray diffraction (XRD). The contents of crystalline minerals and amorphous matters were calculated using Siroquant software based on the XRD pattern of coal ash, and the chemical compositions of amorphous matters in coal ash at high temperatures were studied using the subtraction method. The results show that the content of crystalline minerals and amorphous matters in coal ash and the variation of chemical composition of amorphous matters in coal ash at different temperatures could be obtained using Siroquant and chemical analysis. The form of amorphous matters in coal ash varies with temperature. The amorphous matters in the coal ash exist in the form of non-crystalline oxides below 1100℃ and they transform to vitreous materials above 1200℃ because some crystalline minerals melt at high temperatures. The low Si/Al ratio of coal ash is beneficial to the formation of mullite at high temperature.