Understanding filter cake formation through electrical impedance measurements TarletonSteve HoldichRichard WillmerS.A. 2009 An electrical impedance tomography technique for determining the solids concentration in solid/liquid mixtures has been used to analyse cake formation during the pressure leaf filtration of aqueous based mineral suspensions. The experimental data are interpreted through so-called ‘modern filtration theory’ which serves to highlight some of the difficulties that currently exist in the areas of both modelling and scale-up in solid/liquid separation.