Representative Cu L3-edge absorption spectrumof Cp sample treated
with xanthate at oxidative conditions showed dominant single peak at
932.6 eV attributed to CuI species intrinsic to Cp (Fig. 7C-5). A broad
unresolved and hence poorly-defined component near 933.8 eV was attributed
to adsorbed CuEX. The absence of pre-edge peaks between 930
and 931.3 eV associated with the CuII state indicates the absence of the
CuII oxides at the Cp surface at oxidative conditions. The Fe L2,3-edge
absorption spectrum (Fig. 7D-7) showed leading peak at binding energy
707.2 eV that has been attributed to FeIII in Cp. The lack of a strong contribution
at 711 eV indicates that the surface of Cp was mildly oxidised
and covered with hydrophobic CuEX species. This explains the high
recovery (97%) of Cp at oxidative conditions.