Filtration and Drying Characteristics of Red Mud

Abstract

This paper deals with filtration and drying characteristics of red mud which is a waste from Bayer process to produce alumina.
First, the equilibrium porosity and the local specific filtration resistance of red mud slurry were measured at various compressive pressures and experimental equations were obtained. The Ruth's coefficient in a case of constant pressure filtration was calculated on the basis of the modern filtration theory and the Ruth's theory, respectively, and the both calculated values were compared with experimental data.
Secondly, shrinkage characteristics and drying rate of the sample bed prepared by forming wet red mud into a cylindrical shape were measured. The results indicated that the shrinkage characteristics could be estimated from the data of the true density of red mud, the moisture content of the sample bed and the specific volume of the dried sample bed. Furthermore, it was clarified that drying rates were affected by the solute material in the red mud slurry deposited at and near drying surface.