Pore characteristics of cake by filtration based on LBM-DEM-DLVO coupling method

Abstract

Slurries containing fine particles are widely dewatered by flocculation combined with filtration. Understanding the microscopic filtration process of a flocculated slurry is helpful in designing flocculation and filtration schemes; however, there is currently limited research. In this study, the Lattice Boltzmann method–Discrete Element method–DLVO coupling method (LBM–DEM–DLVO) was used to conduct numerical experiments on the pore characteristics of cake by filtration. The numerical results demonstrate that the cake formed by filtration of the flocculated slurry contains two types of pores: interfloc and intrafloc pores. The diameter of the interfloc pores, which are the dominant channels for water seepage in the cake, is relatively large. The pore properties of the cake were significantly influenced by the interaction force between the particles in the floc and the filtration pressure; the mechanism was analyzed. Engineering proposals for dewatering are also presented. A multi-stage pressure treatment process and increased Finter during flocculation are recommended.