高岭土对准东煤结渣特性及矿物质演变的影响

采用热分析和X射线衍射物相分析相结合的方法,对添加高岭土前后的准东煤灰矿物质组分随温度的演变规律进行了研究,分析了高岭土对准东煤结渣特性的影响。结果表明,准东煤中原始矿物质以方解石、硬石膏、石英为主,高温下主要是镁硅钙石和硅酸二钙;掺混高岭土后准东煤灰熔融温度呈现先下降后上升趋势。掺混比例为3%时,准东煤灰以钙黄长石、铁橄榄石、镁硅钙石为主,三者易形成低温共融物,导致此比例下灰熔融温度大幅降低;添加比例超过6%后,灰中矿物质由易形成低温共融的钙黄长石向高熔点的钙长石转变,ST温度快速上升至1 380 ℃;结渣指标计算结果表明,高岭土在原煤中掺混比例达到6%时,能够有效缓解准东煤结渣。

Effect of kaolin on ash slagging and mineral conversion of Zhundong coal

The XRD and TGA were used to study the ash slagging and mineral conversion of Zhundong coal(ZDC) by adding different amounts of kaolin. The results show that the original minerals in Zhundong coal mainly include calcite, anhydrite and quartz, and merwinite and dicalciumsilicate are produced at high temperature. With the increase in the blending ratios of kaolin, the ash fusion temperature decreases at first, but increases later. After adding 3% kaolin into ZDC, gehlenite, fayalite, and merwinite are the main minerals produced at high temperature, which resulting in a low tempereture eutectic. When the blending ratio is above 6%, anorthite becomes the main mineral that have a high melting point, causing a great increase of ash fusion temperature to above 1 380 ℃. The slagging index calculation shows that the kaolin can relieve the slagging degree of ZDC obviously when the blending ratio is above 6%.