Metal removal kinetics and metal ion selectivity in ion flotation were stud
ied from a thermodynamic perspective. Surface tension data could be used wi
th the Gibbs adsorption equation to quantitatively predict the metal-ion re
moval kinetics in alkylsulfate-Cu systems. However, surface tensions predic
ted cation selectivity coefficients in the sodium dodecylsulfate (SDS)-Cu-C
a and SDS-Cu-Pb systems rather poorly, although the predicted order of the
selectivity, (Cu2+ < Ca2+ < Pb2+) was correct. Another thermodynamic select
ivity model, which used the Grahame adsorption equation and a geometrical a
nalysis, predicted cation selectivity coefficients that agreed very well wi
th experimentally, measured values.