Characterisation of concentrates of heavy mineral sands by micro-Raman spectrometry and CC-SEM/EDX with HCA

The effectiveness of electrostatic separation of zircon and TiO2 phases during the processing of heavy mineral concentrates derived from heavy mineral sands depends upon the chemical, physical and mineralogical characteristics of the concentrates. Here the authors’ demonstrate the use of combined micro-Raman spectrometry (MRS), scanning electron microscopy (SEM) and computer controlled scanning electron microscopy coupled with an energy-dispersive X-ray detector (CC-SEM/EDX), followed by hierarchical cluster analysis (HCA) to determining these characteristics on samples from the non-magnetic fraction of the Richards Bay (South Africa) heavy mineral concentrate. All samples were found to be predominately comprised a heterogeneous population of grains of zircon and rutile and other TiO2 polymorphs with diverse physicochemical properties. Combined MRS and CC-SEM/EDX enabled the identification of textural characteristics which impacted on the efficiency of electrostatic separation of zircon and rutile concentrate streams.