Rapid gangue mineral concentration measurement over conveyors by NIR reflectance spectroscopy

Near-infrared (NIR) reflectance spectroscopy is being used increasingly as a laboratory technique to supplement XRD analysis and other measurements of blast-hole cuttings for metallurgical processing decision making. The advantage of the technique is the speed of measurement and the lack of need for sample preparation. NIR is a surface measurement that responds to transition element, electronic transitions and molecular, vibrational transitions in crystal lattices. The constituents of a sample are quantified by creating predictive models by regression against primary sample analyses through XRD, XRF and CEC. e developed predictive models for concentrations of swelling clays, kaolinite, muscovite and biotite from conveyor samples of copper ore using a QS 8000 over-the-conveyor system. The results are precise enough to be used for real-time, process decision making. In addition, prediction models have also been developed for seven oxides in limestone conveyed to stockpiles in cement plants.