X-PEEM in combination with XPS, ToF-SIMS and UV–vis techniques
has been effectively used for the study of surface chemistry of Cp particles
of size d80 of 20 μmat oxidative and reductive pulp conditions. For
Cp treatedwith xanthate at an oxidative pulp potential, TEY Cu L3 and Fe
L2,3-edge NEXAFS spectra have shown the surface of the Cp was mildly
oxidised and covered with adsorbed molecular CuEX. A small amount
of FeIII oxidation products was observed. When the Eh was reduced to
−100 mV, an increase in concentration of CuI and FeIII oxides and
hydroxideswere detected. Cu L3-edge NEXAFS has also shown the presence
of low percentages of CuII oxides (CuO or Cu(OH)2) and a thicker
internal layer of CuI oxide (Cu2O). Extensive oxidation of Cp particles
caused low recovery at reductive pulp conditions. In each case, there
were small changes in surface speciation between particles.