Fuel, Vol.94, No.1, 52-63, 2012
Multianalytical approaches to the characterisation of minerals associated with coals and the diagnosis of their potential risk by using combined instrumental microspectroscopic techniques and thermodynamic speciation
A routine multianalytical methodology based on the combination of Optical Microscopy (OM) with instrumental microscopic techniques like Electron Microscope (HR-TEM and SEM) coupled to Energy Dispersive X-Ray Spectroscopy (EDS), Confocal Microscopy (CM) and Micro-Raman Spectroscopy (MRS) provides a powerful approach for the research of the mineralogical composition. Coals from different origins (five continents) and different mineralogical composition were selected for analysis. The analytical approach makes use of OM to select the different mineral phases associated to coal samples with subsequent use of the instrumental microscopic techniques on selected targets. The SEM/EDS, HR-TEM/EDS, and MRS analysis showed no significant differences in the chemical composition of the main minerals found associated to coal, such as oxides, sulphides, sulphates, silicates, carbonates, and others. The instrumental techniques provide fast, non-destructive and highly-selective analysis of both the whole coal and particle surfaces. Moreover, thermodynamic speciation through chemical modelling simulations gives the required information to confirm the stability of secondary minerals detected in the samples and helps to diagnose the potential environmental risks associated with weathering. (C) 2011 Elsevier Ltd. All rights reserved.
Keywords:Minerals;Multianalytical approach;Non-destructive techniques of characterisation;Diagnosing potential impacts;Thermodynamic speciation