The use of optical reflected light and SEM imaging systems to provide quantitative coal characterisation

• Published in: Minerals engineering Vol. 24; no. 12; pp. 1299 - 1304
• Main Authors: O’Brien, G., Gu, Y., Adair, B.J.I., Firth, B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2011
• Subjects: Automated imaging; Coal; Coal mines; Constituents; Imaging; Liberation analysis; Macerals; Minerals; Reflectance; Scanning electron microscopy; Automated imaging; Coal; Liberation analysis
• ISSN: 0892-6875; 1872-9444
• DOI: 10.1016/j.mineng.2011.04.024

► Identified and tested a new method for preparing coal samples for analysis in both optical and SEM systems. ► Investigated the feasibility to reliably analyse the same coal samples by both systems. ► Formulated a practical pathway for obtaining integrated maceral and mineral information on a particle by particle basis. Emerging energy markets demand coal products with significantly different quality specifications to those used in coke making and conventional power generation. The suitability of different types of coal as particulate fuels requires a fully quantitative understanding of the nature and associations of both mineral and maceral constituents in individual coal particles. This characterisation defines not only the chemical attributes of coal assemblages, but also a predictive understanding of utilisation performance. Particle characterisation information is traditionally obtained using a combination of optical imaging methods for the organic constituents and SEM based determinations for detailed mineral information. New preparation methodologies have been developed to allow coal samples to be analysed much more effectively by both optical and SEM systems. Optical microscopy measurements of coal reflectance are traditionally carried out using an oil immersion lens. Recent tests show that measuring maceral reflectance in air can produce equivalent results to measurements made using an oil immersion lens. Thus a workflow is possible that makes for fast effective collection of data from both systems from the same surface. These developments are important precursors to fully integrating an optical imaging system with the latest SEM based developments on the FEG platform.