A slit pore membrane is used for a membrane filtration of silica suspensions of two concentrations: a relatively low volume fraction when supposedly only pore blocking mechanism is responsible for a membrane flux decline and a relatively high volume fraction when cake layer formation is supposed to dominate. A theory is developed for both cases. It is shown that the membrane filtration proceeds in two different regimes depending on the applied pressure difference and the theory is developed for both cases. It is shown that the theory predictions are in a reasonable agreement with our experimental data. (C) 2012 Elsevier B.V. All rights reserved.