Air Dispersion and Bubble Characteristics in a Downflow Flotation Column

Bubble Sauter mean diameter and aeration rate of a gas-liquid system in a laboratory downflow flotation column were explored. Both critical coalescence concentration and Sauter mean diameter decreased with increasing superficial liquid velocity, and also the Sauter mean diameter was found to obviously increase with the increase in the sampling height under low dodecylamine concentration. The aeration rate increased as the dodecylamine concentration increased at a constant valve opening degree and also linearly increased as superficial air velocity increased at a constant superficial liquid velocity of 11 cm/s. Compared to the superficial air velocity, the dodecylamine concentration was found to present a larger effect on the Sauter mean diameter but a smaller one on the aeration rate within the studied ranges of the dodecylamine concentration and superficial air velocity.

本研究针对实验室下行浮选柱内气液体系的气泡索特平均直径（Sauter mean diameter）与充气速率展开探究。结果表明，临界聚结浓度（critical coalescence concentration）与索特平均直径均随表观液速（superficial liquid velocity）升高而降低；在低十二胺（dodecylamine）浓度条件下，索特平均直径随采样高度（sampling height）增加呈现显著上升趋势。当阀门开度固定时，充气速率随十二胺浓度升高而增大；在表观液速固定为11 cm/s的工况下，充气速率随表观气速（superficial air velocity）呈线性增长。在本次研究所覆盖的十二胺浓度与表观气速范围内，相较于表观气速，十二胺浓度对索特平均直径的影响更为显著，而对充气速率的影响则相对较弱。