Study on internal flow field and flotation performance of a vortex-driven flotation cell for fine minerals

Abstract

The efficient recovery of fine minerals remains a major challenge in mineral processing. Flotation is one of the primary methods for fine particle separation, and from the perspective of flotation dynamics, turbulence intensification is essential. In this study, a novel vortex-driven flotation cell for fine mineral particles was designed, and its flow field characteristics and flotation performance were investigated through computational fluid dynamics simulations and flotation experiments. The simulation results indicate that the mineralized zone exhibits high turbulence dissipation rate and 20%–30% gas volume fraction, providing an energetic environment for particle-bubble collisions; the cyclonic zone generates moderate swirling, enabling density-based separation of middlings and tailings; and the foam floating zone maintains steady flow with turbulence intensity less than 5% of that in the mineralized zone, ensuring stable flotation of mineralized bubbles. Further investigation of the radial and axial arrangement of vortex mineralization tubes shows that a radial distance of 0.5R maximizes turbulent kinetic energy in the mineralized zone, enhancing fine particle-bubble mineralization, while an axial distance of 0.33H produces appropriate swirling intensity in the cyclonic zone, promoting both middlings-tailings separation and bubble rise. The flotation results of − 45 μm middling coal show that the vortex-driven flotation cell with 0.5R–0.33H arrangement achieve a 2.76 percentage points increase in yield and a 3.99 percentage points improvement in recovery of combustibles compared with conventional flotation column under the same conditions. The device demonstrates potential for industrial scale-up, providing a new approach for the efficient recovery of fine minerals.