High pressure dewatering rolls Mark-II: A novel dewatering technology for mineral tailings

• New HPDR Mk-II prototype improves fine tailings dewatering using wedge wires. • Operates continuously, with comparable or better performance than filter presses. • Copper and nickel tailings achieved 83.1 wt% and 87.9 wt% solids, respectively. • Partial submersion improves desaturation, enhancing dewatering in nickel tailings. High Pressure Dewatering Rolls (HPDR) is a continuous, high pressure, cloth-less filter designed to improve solid–liquid separation. The Mark-I prototype demonstrated cake solid concentrations comparable to those of conventional filter presses during trials with various industrial suspensions. A further development (HPDR Mk-II) is described here. It is designed for mineral tailings, features a larger filtration area, improved handling of fine particles using 30 µm wedge wires as the filter surface, and the potential for cost reductions in achieving low moisture content. This study overviews the design, proof of concept (phase 1) and safe and continuous steady state operation (phase 2) of the device. Phase 1 demonstrated operation using both flocculated and non-flocculated copper tailings (D[3,2] = 5.84 µm) and phase 2 showcases operation in runs up to one hour with nickel tailings (D[3,2] = 9.33 µm) under varying conditions. Thorough material characterisation of the tailings was conducted for benchmarking purposes. The HPDR achieved filter cake moisture contents of 83.1 wt% for copper and 87.9 wt% for nickel tailings, with a maximum specific solids throughput of 302 kg/m 2 .hr for nickel and 73 kg/m 2 .hr for copper. The cake moisture and specific throughput were comparable to or better than filter press performance, but with the advantages of continuous, cloth-less operation.