利用X射线衍射仪(XRD)分析高温煤灰熔融机理

High Temperature Coal Ash Fusion Mechanism by X-Ray Diffraction(XRD)

选择3种不同灰熔融温度的煤,在弱还原性气氛下,利用XRD考察不同加热温度下煤灰熔融过程中的矿物演变过程,并对煤灰的熔融机理进行探讨。结果表明:3种煤中的晶体矿物主要有高岭石、石英、方解石、石膏和黄铁矿等,煤中高岭石和石英的含量与煤灰熔融温度成正相关影响。煤中方解石、黄铁矿和石膏含量与煤灰熔融温度成负相关影响。815℃煤灰中晶体矿物主要为石英、硬石膏和赤铁矿等。随着加热温度的升高,煤灰中石英、硬石膏等结晶矿物含量逐渐减少,生成新的矿物。莫来石的生成是导致煤灰熔融温度高的主要原因。低灰熔融煤灰在加热过程中,1 100℃时少量铁钙辉石的生成起到了降低煤灰熔融的作用。

By using the advanced instrumentation of X-ray diffraction（XRD）,the mineral matter of three coals with different fusion temperatures and mineral transformation of three coal ashes in reducing conditions were studied.The results show that the coal mineral phases generally include kaolinite,quartz,calcite, gypsum and pyrite.The mineral phases of coal ashes which are ashed at 815 ℃ generally include quartz,hematite,and anhydrite.As the heating temperature increases,the content of quartz, anhydrite and hematite in coal ash will decrease in reducing conditions and some new mineral phases are formed during the heating processes.The new phase of mullite formed is the main reason of high fusion temperature of coal ash samples.Otherwise, the hedenbergite formed at 1 100 ℃ in the heating process is the main reason for lowering the ash melting temperature.