Cathodoluminescence and reflected light correlative microscopy for iron ore characterization

摘要

Image analysis aiming at process design or control might be based on several types of microscopy, each providing advantages and limitations. Automated mineralogy systems based on SEM are dominant for ore characterization, but there are relevant cases where such systems cannot perform the required characterization, as iron ores and complex multi-metallic rare-earth ores.The characterization of iron ores is typically performed using reflected light microscopy. Optical image analysis systems can recognize most common iron-bearing minerals, but the discrimination between quartz, other transparent gangue minerals and the embedding resin is very tough.Here we present a correlative microscopy setup that combines reflected light and cathodoluminescence. The correlated use of reflected light and cathodoluminescence signals provided contrast to discriminate epoxy resin from transparent minerals allowing the segmentation and measurement of gangue minerals and iron oxides in an iron ore sample. The obtained results were validated in comparison to measurements from SEM images of the same fields.