The ion exchange dynamics of a ternary Cu2+-Zn2+-Na+ system in a fixed-bed column was described by a mathematical model. The modeling considered the external and internal mass transfer limitations and thermodynamic equilibrium on the liquid-solid interface, described by the mass action law. To validate the model experimental data were obtained on the ion exchange in a fixed-bed column for the ternary system using Amberlite IR120 resin. In the simulation, none of the model parameters were obtained from fitting to the experimental breakthrough curves of the ternary system. In the model, the values for the external mass transfer coefficients were calculated from empirical relations whereas the internal mass transfer coefficients and mass action law parameters were obtained from the literature, determined from the constitutive binary systems. The model was able to reproduce the experimental breakthrough data under different operating conditions. (C) 2012 Elsevier B.V. All rights reserved.