The influences of mineral behaviour on blended coal ash fusion characteristics

The ash fusion characteristics and mineral behaviour of three kinds of individual coal ash and a series of two-component blended ashes were studied. The ash fusibility and chemical composition were measured and analysed. The samples were heated progressively from 800 degrees C to the initial deformation temperature (IT) at 100 degrees C intervals in reducing atmosphere. Mineral composition and type at each temperature interval were determined by X-ray diffraction (XRD) analysis. The results show that blended ash softening temperatures do not change linearly with blending ratios. It can lie between or lower or higher than that of the individual parent coals. Some combinations of component coal's mineral produce low-melting eutectic minerals at high temperature and this is the main reason causing the non-arithmetic averaging of softening temperature of blended ash. It is consistent with the results from the ternary system phase diagram. (C) 1999 Elsevier Science Ltd. All rights reserved.