High pressure dewatering rolls: Effect of process variables on cake solids concentration and throughput

Abstract

The High Pressure Dewatering Rolls (HPDR) is a novel solid–liquid separation technology that combines compression, vacuum, and shear to enhance dewatering of fine mineral suspensions without requiring filter cloths. This study explores how roller speed, shear, feed concentration, flocculation, particle size distribution, and minimum roller gap affect HPDR performance using well-characterised calcium carbonate suspensions. Increasing roller speed reduced cake solids concentration due to shorter dewatering times, but increased solids throughput up to an optimal speed near 4 rpm. At 7 rpm, throughput decreased due to material floating on top of the rollers and not passing through the nip effect..