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

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.