灰化温度对准东煤灰组分分析的影响

Effect of ashing temperature on analysis of Zhundong coal ash

采用等离子低温灰化法和国标缓慢灰化法,在灰化终温T<200,500和815℃下,分别制备了3种准东煤的灰样,使用XRF,TG-DSC和XRD分析比较了灰化温度对灰组分分析的影响。实验发现,准东煤中Al,Si,Ti等在灰化过程中基本无释放,Na/Ca/Mg在500℃时有少量释放,在815℃时大量释放。中温灰与低温灰的矿物组分相似,主要区别是低温灰中的高岭石在中温灰中转变成了偏高岭石。低温灰中仍有部分未充分氧化的有机质。而高温灰与中、低温灰相比有明显差异。准东煤灰成分分析不宜采用现有国标中的缓慢灰化方法,而应使用等离子低温灰化法或者采用灰化终温不超过500℃的缓慢灰化法。

Ash samples of three Zhundong coals were prepared at low,medium and high final ashing temperatures,respectively at T〈200 ℃,500 ℃ and 815 ℃,by using the low temperature plasma ashing method and the slow ashing method specified in Chinese national standard. The effect of ashing temperature on the ash composition evaluation was compared and analyzed. It is found that little Al,Si and Ti release during the ashing process. A small amount of Na /Ca / Mg release at 500 ℃,while a large amount of Na / Ca / Mg release at 815 ℃. Minerals in the medium temperature ashes are similar to those in the low temperature ashes,but significantly differ from those in the high temperature ashes. Kaolinite in the low temperature ashes is transformed to meta-kaolin in the medium temperature ashes. There is still some organic matters left in the low temperature ashes. The existing national standard is not suitable for the evaluation of Zhundong coal ashes. Instead,the low temperature ashing or slow ashing below 500 ℃ are suggested.