Microscopy in mineral processing - A review

With gradual depletion of high-grade ores, the future need for metals has to be met by exploiting low and off grade ores of increasing complexity. Recovery of by-products has also become an economic necessity. Environmental considerations have made it necessary to eliminate minerals containing noxious impurities. Extrative process must not only operate withing these constraints, but also in addition be economical, zero-waste technology and environmental friendly. In order to design the most viable process, it is imperative that both qualitative as well as quantitative mineralogical information is available on the ore, beneficiated/processed intermediates, rejects and end products. Mineral processing is an nature in the form of minerals, hence mineralogical characterisation is a useful intitial step for mineral processing. Optical (reflected and/or transmitted light) and electron micoscopy (SEM-WDS-EDS and/or EPMA) are most indispensable tools for minerals characterisation. However, the other necessary data in the form of chemical analysis can readily be supplied by a number of methods, which is also useful in charaterisation studies. This paper reviews the applications of mineralogical information, obtained through microscopic studies, in the process and/or flow sheet developments of mineral processing. The information contained in this paper represent contributions from a distinguished and international assembly of researchers and practicing mineral engineers working with complex ores.