Investigation on ash fusibility of two coals with different particle size and their blends
A typical coal with high ash-melting-point from Huainan and Huaibei mining area(HN)and an Inner Mongolia coal with low ash-melting-point blended coal(ER)were selected and sieved into four distinct particle size ranges of>150 μm,75～150 μm,48～75 μm,and<48 μm,respectively.The mass ratio and ash yield in each particle size range were analyzed.The ash chemical composition,minerals,and liquid phase formed during ash melting were determined by XRF,XRD,and thermodynamic equilibrium calculation,respectively.The effect of particles size on the ash fusion temperature was investigated through mixing HN coal with ER coal with different particle size.The results indicated that the average ash parti-cle size of HN coal increased with the increase of coal particle size,and the average ash particle size of ER coal was around 3 μm when the particle size of ER coal was>48 μm;the ash yield of HN coal in-creased with the increase of coal particle size while the ER coal was opposite.The ash chemical composi-tion of the coal with different particle size was inhomogeneous.The AFTs of HN coal increased with the increase of coal particles while the AFTs of ER coal decreased.When HN coal blended with ER coal with different particle size,respectively,the ash fusion temperatures of the mixed coal was between them.When the HN coal(<48 μm)blended with the ER coal(>150 μm)in a mass ratio of 1∶1,high melting pointe mineral of mullite in ash was converted to low-melting point mineral of anorthite,resulting in the lowest FT of 1 317℃.
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