Utilization of entrainment for a gravity based recovery of ultrafine particles

Ultrafine particle recovery poses a complicated challenge to be solved, due to the low collision efficiency with bubbles in flotation processes and a high recovery of gangue material by entrainment. As a result, losses of valuable metals occur. In the present work, a novel approach was chosen for the recovery of ultrafine particles. Instead of flotation, entrainment was used for a gravity based particle recovery. A 3D-printed particle collector was designed to recover the particles at the top of a bubble column. To obtain a good understanding about the density dependence of the process, SiO 2 , Ni and W particles were used to cover a density range of 2.65-19.28 g ⋅ cm -3 . High recoveries were achieved for Ni (73 %) and W (59 %) particles. SiO 2 was only recovered in high amounts ( ≈ 50 %) when particle sizes exceeded 10 μ m . An extensive investigation of the flow regime was performed to gain an overview about the correlation in between flow regime and particle recovery results. • 3D-printed design for ultrafine particle recovery. • Ultrafine particles have been recovered successfully via entrainment. • Selectivity for heavier particles smaller than 10 μ m