The Floatex Density Separator (FDS) is a classifier-concentrator. In the concentrator fluidization coupled with hindered settling leads to separation in a teeter bed column. Due to the apparent density of the suspension, the viscosity of the bed offers more resistance and particles settle in terms of the drag force. The separation principle of the FDS is complex, hence it was decided to study separation based on size alone by considering interactions between different process parameters to predict the performance of FDS. The effects of four important operating parameters set point, teeter water flow rate, feed rate and pulp density of feed on the performance of the FDS have been studied through simulation. From the theoretical values, interaction between various process inputs has been studied. A detailed understanding has been established about particle behavior under different feed input conditions for pure silica (S.G. 2.65). The predicted values are validated against the experimental results. It was found that variations in TW flow rate and feed rate are predicted with considerable degree of accuracy. (C) 2011 Elsevier B.V. All rights reserved.