Mineralogical Composition of the Highvale Mine Coals and Its Impact on Plant Performance

Abstract

Abstract Mineralogical analysis of the Highvale Mine coals using X-ray diffraction (XRD) shows quartz, kaolinite, illite, and feldspars to dominate. Minor amounts of carbonate and unknown hydrate minerals are also present, and most minerals reported by XRD have been verified by scanning electron microscopy-energy-dispersive X-ray spectrometry (SEM-EDX) on selected samples using back-scattered electron imaging on coal pellets, The coal ash indices show the Highvale Mine coals to have low to medium propensity to form slagging or fouling deposits in the boilers. The relationship between ash content of mill samples and opacity in the electrostatic precipitators (ESPs) is not clear. However, there appears to be a correspondence between ash resistivity and ESP performance. As resistivity is a function of ash chemical composition, the differences in ash composition, notably in its Fe2O3 content, may have contributed to the increase in opacity recorded for seam 1. The production of submicron particles, via fragme...