哈尔乌素煤中矿物固相反应对煤灰熔融特性的影响

Influences of Minerals Solid Phase Reaction on Melting Characteristics of Coal Ash in Haerwusu Coal

以鄂尔多斯地区哈尔乌素煤为研究对象,利用光学显微镜和X射线衍射(XRD)等手段分析了煤中主要矿物组成,研究了助熔剂SiO_2,Fe_2O_3和CaO在不同添加量下对哈尔乌素煤灰熔融性温度的影响。利用FactSage软件中的Equilib模块,模拟了添加助熔剂前后煤中矿物的固相反应过程。结果表明:超过1 250℃后,哈尔乌素煤灰中的主要成分是长石和刚玉,刚玉质量分数超过了40%,这是原煤煤灰熔融性温度较高的重要原因。原煤中分别添加7%(质量分数,下同)的SiO_2,10%的Fe_2O_3和12%的CaO后,煤灰熔融温度降低幅度较大。高温下煤灰中部分耐高温矿物与助熔剂发生了固相反应,生成的低熔点矿物和低温共熔物是煤灰熔融性温度降低的直接原因。

Taking Haerwusu coal in Erdos as the researching project, utilizing methods of optical microscope and XRD, the main mineral composition in coal was analyzed. After adding fluxes such as SiO2, Fe2O3 and CaO with different ratios, how those fluxes affected the ash melting temperature of Haerwusu coal was researched. Utilizing the Equilib module in FactSage software, the solid phase reaction process of minerals in coal before and after addition of fluxes was calculated and simulated. The research results show that after 1 250 ℃, the main contents of Haerwusu coal ash are feldspar and corindon, the ratio of corindon is beyond 40%, that is the main reason why the ash melting temperature of raw coal is relatively high. After adding 7% SiO2, 10% Fe2O3 and 12% CaO in raw coal, the decrease of ash melting temperature is relatively big. The solid phase reaction has happened between part of high temperature resistant minerals and fluxes, the low melting point minerals and low temperature eutectic formed by the reactions are the direct reasons which lead to decrease of ash melting temperature.