Abstract: The drum cone angle is the most important design parameters in the horizontal screw centrifuge, and its size has important implications to the sediment moisture rate. It can only select the cone angle based on the experimental data parameters at present. This method is time-consuming and labor-intensive, and can not find the best angle due to the experimental error. Firstly, combining with the characteristics of the mud buildings, the laws of solid-liquid separation of drum cone is studied by using FLUENT software. Then, the cone angles of 6 °, 7.5 °, 9.5 °, 12 ° are selected to model and mesh. The drum velocity field of decanters under different cone angle is simulated and analysed. Finally, the double tapered drum of large diameter decanters is designed to meet the building mud. The simulation results show that the maximum sediment thickness is closer to the sub-discharge port when the cone angle is 9.5 ° which is an optimal cone angle parameter. The designed double tapered structure of the cement separation liquid moisture has a higher handling capacity and lower moisture content, so the structure of the whole performance is greatly improved and the work efficiency of decanters is increased

Key words: Cone angle, Drum, Horizontal screw centrifuge, Parametric optimization