Pore structure and network analysis of filter cake

Abstract

Filtration is an important solid–liquid separation technology employed widely in the mineral processing industries. The effectiveness of the filtration operation can be influenced by numerous variables, related to the particulate phase, the slurry rheology and the equipment. Continuous filtration of fine particles involves filter cake formation and removal of surface moisture by drawing air through the pore structure network. In order to gain a better understanding of the complex transport phenomena that occur in the filter cake, analysis of the effect of the three-dimensional pore geometry on the effective transport properties of the filter cake is necessary. In this regard, analysis of the pore connectivity in a packed bed of particles should allow for a detailed description of fluid flow and transport in the filter cake structure. Two interrelated approaches, namely computer simulation and experimental measurement, can be used to gain knowledge of pore microstructure and its correlation to macroscopic cake properties. In this regard, a three-dimensional Monte Carlo method was used in this work to simulate cake structure. As the resolution and the techniques for three-dimensional geometric analysis have advanced in the last decade, experimental measurements are now possible to specify in detail the pore structure in three-dimensional digital space using high-resolution X-ray microtomography. Thus in addition to computer simulation, this paper presents preliminary experimental findings of pore structure in three-dimensional using X-ray microtomographic techniques. These experimental results are contrasted to results from computer simulation.