TOF-SIMS Statistical Analysis of Surface Hydrophobic/Hydrophilic Species Ratios and Contact Angle Estimation in Real Ore Systems

摘要

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has been used to derive statistical differences in surface concentrations and lateral distributions of hydrophobic and hydrophilic species comparing flotation concentrate and tail samples. Differences between particles of the same mineral phase (chalcopyrite) and distribution of particular species across individual particle surfaces have been measured in single mineral and ore samples. An objective of this study was to derive the contact angle of chalcopyrite particles in an ore from the TOF-SIMS hydrophobic/hydrophilic indices using a calibration curve of contact angle versus TOF-SIMS indices for chalcopyrite in single mineral experiments. This derived contact angle can then be used to calculate the flotation rate constant and recovery of that mineral in the ore. A good correlation was obtained between TOF-SIMS hydrophobic/hydrophilic indices, the amount of collector adsorbed, contact angle and flotation recoveries of chalcopyrite in single mineral and in Ok Tedi ore systems. Differences between collector (DTP) distributions on concentrate and tail samples can be statistically separated. Hydrophilic species concentrations such as calcium and metal hydroxides were found to be statistically higher on chalcopyrite in tailings than on the concentrate particle surfaces. TOF-SIMS data were used to produce various hydrophilic and hydrophobic indices derived from selected pairs of related measures eg: Ca~+/Fe~+, FeOH~+/Fe~+, SO_3~-7S_2~-, DTP~-/SO_3~-.The statistical basis of analysis allows identification of surface chemical factors discriminating between particles of a particular mineral phase that report to concentrate or tails. The method suggests that it will be possible to assess conditioning of sulfide surfaces for optimum selectivity.