Analysis of Phosphate Ore Samples by Wavelength Dispersive X-Ray Fluorescence Spectrometry (WDXRFS): Implications for Grade Control during Mining and Process Optimization

ABSTRACT The mining and beneficiation of low-grade phosphate ores has become inevitable due to its increasing consumption for fertilizers. Controlling of ore grade through blending and beneficiation of low-grade ore requires extensive chemical analysis in each step for optimizing process parameters. To facilitate rapid analysis of phosphate ore a new analytical procedure has been developed using sequential WDXRF spectrometer. A set of international certified reference materials (CRMs) and well-characterized in-house standards of phosphatic siliceous dolostone of the Vempalle Formation, Cuddapah basin were utilized for calibration of the analytical signals. The newly developed analytical procedure has been tested by analyzing major oxides in four natural samples of phosphate ore from the Proterozoic Jhamarkotra rock phosphate deposit, Udaipur, Rajasthan. The analytical results indicate wide tolerance ranges of the calibration lines especially for CaO, P2O5, SiO2 and MgO. The results were subsequently validated with the data obtained on the same set of samples by Inductively Coupled Plasma-Optical Emission Spectrometric (ICP-OES) technique. The comparison shows that the precision and accuracy of WDXRFS data for CaO, P2O5, and SiO2 in phosphate ore are well within the statistically acceptable range i.e., <1% and 5–10% respectively, except for other major oxides at low (<1 wt.%) concentrations. This study reveals that WDXRFS can be used as a cost effective, rapid and eco-friendly technique for routine analysis of phosphate ore, containing significantly wide ranges of CaO, P2O5 as well as SiO2 and MgO impurities, for grade controlling during mining and optimizing process parameters during beneficiation and extraction.