Copper tailings filtration: Influence of filter cake desaturation

• Cake-to-fabric adhesion and cake cohesion tests were carried out using special test rigs for a tensile testing machine directly subsequent to laboratory filter press tests. • Filtration process parameters (filtration pressure, air blow pressure, and duration of the air blow) can be used to control the properties of the filter cake. • Residual water content and saturation decrease with an increase of the three process parameters, adhesion and cohesion increase. • A simplified mathematical model was developed which describes the desaturation behavior. Copper mining produces immense amounts of tailings due to low ore grades. These residues are increasingly dewatered by filtration in recessed plate filter presses to ensure safer storage and high recovery of water. The process parameters filtration pressure, desaturation time, desaturation pressure and cake thickness have a significant influence on achieving water content as well as bulk material stability specifications and maintaining operation performance, especially with regard to cake detachment. In this study, copper tailings filtration tests in a laboratory filter press and directly connected measurements of cake-to-fabric shear adhesion as well as filter cake shear cohesion were carried out. It is shown that optimization of cake properties with regard to residual water content, suitability for detachment and bulk material stability by specific adjustment of the filtration and post-treatment parameters is possible. Furthermore, implementation of a mathematical model allows water content, cake saturation, cake-to-fabric shear adhesion and cake shear strength prediction dependent on filter cake desaturation time and pressure for tailings filtration applications in recessed plate filter presses.