  We propose a model for the calculation of renormalized charges and osmotic
properties of mixtures of highly charged colloidal particles. The model is a
generalization of the cell model and the notion of charge renormalization as
introduced by Alexander and his collaborators (J. Chem. Phys. 80, 5776 (1984)).
The total solution is partitioned into as many different cells as components in
the mixture. The radii of these cells are determined self-consistently for a
given set of parameters from the solution of the non-linear Poisson-Boltzmann
equation with appropriate boundary conditions. This generalizes Alexanders's
model where the (unique) Wigner-Seitz cell radius is fixed solely by the
colloids packing fraction. We illustrate the technique by considering a binary
mixture of colloids with the same sign of charge. The present model can be used
to calculate thermodynamic properties of highly charged colloidal mixtures at
the level of linear theories, while taking the effect of non-linear screening
into account.
