Fig. 4 shows the ToF-SIMS statistics obtained for the oxidative conditioned,
pH buffered and reductive conditioned samples. The positive
(+) and negative (−) ion signals showed that the surface chemistry
of the Cp samplewas significantly affected by Eh modification (addition
sodium dithionite). At reductive pulp potentials (−97 mV, pH 9) the
amount of sulfur and copper present on the Cp particles was decreased
compared to that of the oxidative conditioned sample, while the
amount of oxides and hydroxide was significantly increased. The
concentration of OC2H5 fragment was also found to decrease at an
Eh ~−97 mV and pH 9. The hydrophobicity and floatability of Cp were
lowered at reductive pulp potentials.