浮选机叶轮工作参数对气泡尺寸分布特征的影响

气泡尺寸是衡量浮选动力学过程及其分选效果的重要依据。叶轮工作参数在根本上决定着流体通道大小和流体特性，进而影响气泡弥散和颗粒悬浮。本研究采用高速摄像机对KYF型浮选机内的气泡进行拍摄和尺寸分析，系统考查叶轮直径、叶轮离底间隙、叶轮转速3个因素两两交互对气泡尺寸分布特征的影响。结果表明，增大叶轮直径、缩小叶轮离底间隙、提高叶轮转速均可使气泡尺寸减小，同时也能改善气泡尺寸分布的均匀性；叶轮直径及离底间隙两个结构参数与叶轮转速之间具有显著的协同交互作用，在较低和中等叶轮转速下，叶轮结构参数对气泡尺寸特征的调控作用更为明显，叶轮转速则是在较小的叶轮直径和较大的叶轮离底间隙下影响更为显著；两个叶轮结构参数相比，叶轮直径对气泡尺寸的调控效应比叶轮离底间隙更显著，同时二者也有一定的交互作用，叶轮直径越大，叶轮离底间隙对气泡尺寸均匀性的影响越明显。研究结果可为浮选机内叶轮尺寸的选择和安装操作参数选取提供依据。

Effect of working parameters of Impeller on the characteristics of bubbles size distribution in Flotation Machine

Bubble size is an important basis to estimate the flotation kinetic process and separation effect. The impeller working parameters fundamentally determined the size of fluid flow passage and the characteristics of fluid, and then affected the bubbles dispersion and the particles suspension. In this research, a high-speed camera was used to shoot the bubbles and analyze bubbles size in a KYF flotation machine, and the interaction effects of two factors in impeller diameter, off-bottom clearance of impeller and impeller speed on bubbles size distribution were systematically examined. The results showed that increasing the impeller diameter, reducing the off-bottom clearance of impeller and increasing the impeller speed all can reduce bubbles size and improve the uniformity of bubbles size distribution. There were some significant synergistic interactions between impeller speed with impeller diameter and off-bottom clearance of impeller. At a lower or medium impeller speed, impeller structure parameters are of more significant importance in regulating bubbles size characteristics. However, the effect of impeller speed is more remarkable at a small impeller diameter or a large off-bottom clearance of impeller. Regarding the two structural parameters of impeller, the effect of impeller diameter on bubbles size is more significant than that of the impeller off-bottom clearance. Moreover, the interaction between them was also certain. The larger the impeller diameter is, the more obvious of the effect of the impeller off-bottom clearance on the uniformity of bubbles size. The results can provide some basis for the selection of impeller size and installation operation parameters in the flotation machine.