Determination of Major and Minor Components in Zinc Concentrate by Wavelength Dispersive-X-ray Fluorescence Spectrometry

A method has been developed for the direct determination of Cu, Si, Mg, Zn, Al, Fe, S, Pb, Ca, As, K, Cd and Mn in zinc concentrate samples using a fusion method by Axios PW4400 XRF spectrometer. The conditions for pre-oxidation on sample preparation were studied using the wet chemical method. A 0.3 g sample with 1 g lithium nitrate and 0.5 mL liquid hydrogen (30%) were loaded into a platinum-gold crucible at room temperature. The sample and oxidants were mixed well by shaking the crucible. The higher sample/flux ratio increased the intensities of the trace elements signals in XRF. A lithium tetraborate fusion agent was applied to reduce the matrix effects among elements. The formula and calibration models of gain on ignition are discussed in this paper. The gain on ignition of the actual sample, which cannot be corrected by the software, was converted to the loss on ignition of a virtual sample. The matrix effects among different elements were corrected by theoretical alpha coefficients and empirical coefficients. The precision (RSD, n=12) of the method was less than 3% for all components except Cd. The detection limits of the method were 6.55-111.24 μg/g. Due to the analysis of CRM (GBW 07163 and GBW 07170 were mixed in a mass ratio of 1∶5) by this method, the obtained results are consistent with certified values.