Synchrotron-based X-ray photoemission electron microscopy (X-PEEM), X-ray photo-electron spectroscopy
(XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and ultraviolet visible spectroscopy were
used to characterize the flotation behaviour of chalcopyrite with xanthate at different processing conditions.
The flotation recovery of chalcopyrite decreased from 97% under oxidative conditions (Eh ~385 mV SHE, pH 4)
to 41% at a reductive potential of−100mVSHE (at pH 9). X-PEEM images constructed from the metal L3 absorption
edges were used to produce near-edge X-ray absorption fine structure (NEXAFS) spectra from regions of
interest, allowing the variability in mineral surface chemistry of each mineral particle to be analysed, and the
effect of pulp potential (Eh) on the flotation of chalcopyrite to be determined. XPS, ToF-SIMS and NEXAFS
analyses of chalcopyrite particles at oxidative conditions show that the surface was mildly oxidised and covered
with adsorbed molecular CuEX. The Cu 2p XPS and Cu L2,3 NEXAFS spectra were dominated by CuI species
attributed to bulk chalcopyrite and adsorbed CuEX. At a reductive potential of −100 mV SHE, an increase in
concentration of CuI and FeIII oxides and hydroxides was observed. X-PEEM analysis was able to show the
presence of a low percentage of CuII oxides (CuO or Cu(OH)2) with predominantly CuI oxide (Cu2O) which is
not evident in Cu 2p XPS spectra.