Abstract: Aiming at the problems of the poor flocculation and sedimentation effect of fine mineral particles in a thicken er,based on the validation of physical experiments,the flocculation and sedimentation behavior was simulated in a ϕ1.2 m lab scale thickener by CFD-PBM coupling method,where the Euler-Euler method and the RNG k-ε model were used to describe solid-liquid interaction and turbulence pulsation,respectively.The results show that the velocity characteristics of both liquid and solid phases within the feedwell of the thickener exhibit essentially consistent distributions and the velocity achieves the highest at the feed inlet.The feed velocity significantly affects the internal flow field and particle flocculation characteristics in the thickener.With the increase of feed velocity,the turbulent kinetic energy dissipation rate increases gradually,while the mean size of flocs firstly increases and then decreases;When the feed velocity is 1.5 m/s,the particles flocculation effect is better than that of other conditions,corresponding to the underflow concentration of about 55% for the thickener,which meets the production needs.The results of this study provide a theoretical basis and practical guidance for the optimization of feed ve locity for the thickener.

Key words: thickener,flow characteristics,flocculation behavior,numerical simulation,feed velocity