配煤和助熔剂降低煤灰熔融温度的矿物学特性研究

主要研究添加助熔剂或配煤降低晋城无烟煤的灰熔融温度。通过X射线衍射(XRD)、热力学计算以及灰熔点测试等手段,研究混煤灰熔融特性及其在变形温度时的矿物学特征,解析其结渣特点。结果表明,原煤灰含量越低,混煤灰熔点降低效果越明显。在配煤添加量为20%时,低灰煤C灰熔点降低趋势最明显,对于高灰煤G,则为30%;助熔剂K对C的灰熔点降低效果比对G的更明显。在混煤灰的变形温度处,出现了长石类矿物质。长石类矿物含量的上升和莫来石含量的下降促使灰熔点快速降低。热力学计算表明,高温下,煤灰中液相物质的产生伴随着钙长石和石英含量的快速下降以及莫来石含量的缓慢降低。钙长石参与了煤灰中液相物质的产生。能够与钙长石作用形成低熔点共熔体的物质的含量决定了它的助熔效果。

Mineralogical properties of lowering coal ash melting temperature using blending coal and fluxing agent

In order to understand the slagging properties of blended coal, different coal blending and flux agent were added to Jincheng anthracites. The X-ray diffraction (XRD), thermodynamic software FactSage and ash fusion temperature (AFT) test were employed to analyze the ash fusion characteristics of blended coals and the mineralogical properties of the blended coal ashes. The results show that the content of ash in coal has an important role in the AFT change of blended coals. The lower the ash contained in raw coal is, the easier the AFT of blended coal lowers. The addition ratio of coal blending is 20% and 30% when the AFT decreases significantly for coal C with low ash content and G with high ash content, respectively. There is more significant fluxing effect of K on C than that on G. It is found that the feldspar mineral is formed at the deformation temperature. The decreasing in contents of mullite as well as the appreciably increasing for feldspar is the main reason for the decreasing of AFT. The thermodynamic analyses indicate that the producing of liquid matter is related to the rapidly decreasing in the contents of anorthite and quartz, as well as slowly decreasing for mullite at high temperature. The anorthite takes part in the formation of liquid matter. The fluxing effect of anorthite depends on the contents of matter which can react with anorthite to produce a melt with lower fusion point.