Pressure filter collection systems: sizing and optimisation

Plate and frame pressure filters are a widely used dewatering technology in both paste fill and dry-stack tailings operations. These filters work by using pressure from a feed slurry pump or membrane squeeze to push liquid through filter cloths, retaining solid particles within the plate chamber. At the end of the process, the filter cake is gravity discharged. Belt conveyor systems are commonly used to collect the discharged filter cake and convey it to downstream processes and facilities. The collector conveyor and downstream systems must consider the dynamics of unloading filter cake from the filter. The batch nature of unloading a pressure filter can cause excessive material surges on the bulk conveying system, often significantly greater than the nominal system capacity. If these material surges are not correctly determined, the downstream system is at significant risk of being undersized or prone to poor performance. By optimising surge capacities through various control arrangements, the risk of spillage and plugged chutes can be reduced and capital expenditure can be lowered by specifying lower capacity belt conveyor systems. This paper covers the surge discharge rate calculations and provides control considerations to reduce downstream surge requirements. It considers both the advantages and disadvantages of the various control options, enabling readers to make informed decisions when specifying bulk conveying systems for receiving pressure filter cake.