Abstract: Based on the discrete phase model of the Euler-Lagrange equation,the concentration fields of three different types of zinc dross under a circulating purification system were calculated by using the numerical simulation method. The result shows that the deposition rate increases with the decrease of zinc dross size. When the zinc dross size is smaller than 80 μm,the order of deposition rate from high to low is suspending dross,top dross,and bottom dross. The average residence time of the top dross in the back area of the strip exit is the longest,and it will be beneficial to the removal of the top dross to install a pumping tube in this area. On the inner part of the V-shaped zone,the mass concentration of the suspending dross is the highest,and it has the biggest influence on the surface quality of steel strips. The main travel area of the bottom dross is close to the bottom of the zinc pot,and the bottom dross cannot adhere to the strip surface and it has minimal impact on the surface quality of steel strips.