Systems of thin platelets are studied by Monte Carlo simulations. The platelets interact by a hard core pair potential and Coulomb interactions associated with a distribution of electrical charges. According to the relative values of the charges localized in the central part and on the periphery of the platelets, it is shown that, at constant density, the system can evolve from an homogeneous fluid phase to a phase where the platelets are associated in clusters which percolate through the simulation cell. We discuss the possibility that this simple model can be a first approximation able to describe qualitatively the behavior of kaolin suspensions when the pH value of these solutions decreases from basic to acid.