Errors in the Laboratory X-ray Absorption Near Edge Structure with Respect to Species Analysis in Slags Considering Leak Radiation

The knowledge on the element species in slags is of great importance for, e.g., process control or recovery of valuable materials. X-ray absorption near-edge spectroscopy (XANES) is a suitable method, especially for slags, since it allows element speciation not only in crystalline but also in amorphous phases. The sample preparation as well as the evaluation via linear combination fitting of reference spectra are relevant influencing factors for the results. Errors can occur due to, e.g., improperly prepared samples, damping effects, and inappropriate reference materials. In this study, the origin of spectral damping was investigated with two lab-based spectrometers on a sample series of Fe2O3 prepared as pellets with different masses. Additionally, an electric arc furnace (EAF) slag served as a complex model sample to determine the influence of dampened spectra on the speciation analysis through linear combination fitting. Powder X-ray diffraction (PXRD), X-ray fluorescence spectrometry (XRF), electron probe microanalysis (EPMA), and inductively coupled plasma optical emission spectroscopy (ICP-OES) were employed as complementary and supporting characterization methods.