Development of a simple and rapid EDXRF method for quantification of ZrO2 and HfO2 in aqueous and organic process stream solutions generated from a zirconium extraction facility

Abstract

A simple and rapid method using an energy dispersive X-ray fluorescence (EDXRF) spectrometer is developed for facilitating the analysis of aqueous as well as organic process stream solutions from a zirconium extraction facility for the quantification of zirconium oxide (ZrO₂) and hafnium oxide (HfO₂). Except for dilution, not much sample preparation is involved in the analysis and accordingly the experimental parameters are optimized. Calibrations are performed separately using a set of synthetic standard solutions of zirconium and hafnium prepared in nitric acid medium for aqueous samples and in TBP + kerosene medium for organic samples. Studies are carried out to examine the effect of free acidity, sample matrix, and sample volume on determination of Zr and Hf and optimization of these parameters has been carried out accordingly for regular analysis. Zirconium oxide (ZrO₂) and hafnium oxide (HfO₂) are calculated from the results for reporting purposes. The results from the EDXRF method are compared with those of a gravimetric (phthalic acid precipitation) method with respect to zirconium and ICP-AES method with respect to Hf. On comparison, the results are found to be in good agreement. Detection limits for the developed method are found to be 0.06 g L⁻¹ for ZrO₂ and 0.03 g L⁻¹ for HfO₂. The developed method is employed for the determination of ZrO₂ up to 200 g L⁻¹ and HfO₂ up to 5 g L⁻¹ in various process stream solutions from a zirconium extraction facility. A RSD of less than 3% has been achieved for ZrO₂ and less than 5% has been achieved for HfO₂ in this method.