Intensification of fine apatite flotation with microbubble generation and inclined plates in the flotation column

Abstract

Microbubbles have received great interest in the flotation of fine particles. A membrane distributor is developed to generate microbubbles for the flotation of fine apatite particles. Massive microbubbles are continuously formed under the shear flow in the membrane tube. Compared with a Venturi tube the membrane distributor achieves better performance in P2O5 recovery and grade. The effects of superficial gas velocity and collector concentration are investigated. It is found that there exists an optimal superficial gas velocity at which the large P2O5 recovery is obtained. The high P2O5 recovery and grade benefit from large concentration of sodium oleate. To further improve the performance of the flotation column, computational fluid dynamics (CFD) simulation is performed to reveal the gas-liquid flow influenced by inclined plates. The spatial pattern of the bubbles is photographed by a high-speed camera and reasonably characterized by the CFD results. Introducing the inclined plates in the column improves the P2O5 recovery. Both experimental observation and simulated data demonstrate that the inclined plates result in the slow circulating flow below the inclined plate. Good bubble-liquid segregation makes the entrained bubbles move upward into the overflow.