X-ray Absorption Near-Edge Spectroscopy Calculations on Pristine and Modified Chalcopyrite Surfaces

Abstract

Understanding chemical modifications on the chalcopyrite surface is an important issue to improve hydrometallurgical processes to recover copper from the mineral. X-ray absorption near-edge spectroscopy (XANES) can be used for this task, but the interpretation of the spectrum and the correlation with chemical changes in the first atomic layers are not straightforward. The present study demonstrates the potential of combining spectrum measurements with theoretical X-ray spectrum simulations to elucidate the chemistry behind weathering of important classes of minerals. We simulated the S and Fe K-edge XANES spectrum for pristine and modified chalcopyrite surfaces using periodic DFT calculations and the transition-potential model. The calculated S K-edge XANES spectra are in good agreement with experimental data and the peaks were attributed using the density of states. The simulated Fe K-edge XANES spectra do not reproduce all features observed experimentally. The effect of surface changes due to reconstruc...