Na_2O质量分数对高碱煤灰烧结强度影响

Effect of sodium oxide content on ash sintering strength of high alkali coal

为研究Na_2O质量分数对高碱合成灰烧结强度的影响,将不同Na_2O质量分数的合成灰制成灰柱并在管式炉中进行烧结实验,使用微机控制万能测试机对灰柱烧结强度进行了测试,使用X射线衍射(XRD)、扫描电子显微镜(SEM)对合成灰的矿物质组成以及微观形貌进行了检测和观察。结果表明:随着Na_2O质量分数的增加,灰柱烧结强度不断增加,灰中含钠物质逐渐由钠长石转化为霞石,含钙物质逐渐由钙长石转化为硅灰石和钙黄长石;霞石、硅灰石、钙黄长石等矿物质形成的低温共熔体会使体系中产生大量液相,促进灰质点扩散过程,使灰柱烧结强度增大;随着Na_2O质量分数的增加,灰颗粒间孔隙不断减小,表面由粗糙疏松变得光滑致密。

In order to study the effect of Na2O content on sintered strength of high alkali synthetic ash, the synthetic ash with different Na20 mass fractions was made into ash column and heated in a tubular furnace. The microcomputer control universal testing machine was applied to test the sintering strength of the synthetic ash, the X-ray diffraction （XRD） and scanning electron microscopy （SEM） were used to detect and observe the mineral composition and microstructure of synthetic ash. The results show that, with the increase of Na20 mass concentration, the sintered strength of the ash increased, the sodium compounds in the ash gradually changed from albite to nepheline, and the calcium compounds gradually transformed from anorthite to wollastonite and gehlenite. The low temperature eutectic system formed by minerals such as nepheline, wollastonite and gehlenite produced a large amount of liquid phase in the system, promoting the diffusion process of ash particles and increasing the sintering strength of the ash column. With the increase of Na20 mass concentration, the observed pore size between the ash particles decreased and the surface of the ash oarticles became more and more smooth.