Abstract The impeller in a mechanical flotation tank plays a key role in keeping particles in suspension, dispersing and breaking-up air bubbles, and promoting particle-bubble collision. However, the turbulent regime generated by the impeller can also affect the pulp-froth interface, destabilising the lower regions of the froth and affecting the overall flotation performance. The effects that pulp zone design modifications have on the froth are, however, poorly understood and have not been well-studied. In this work, we study the impact of impeller-stator design on the performance of a large laboratory-scale flotation tank. Two different impeller designs, with and without a stator, were assessed under a range of air flow rates to determine changes in pulp bubble size, froth stability, and metallurgical recovery. The results allow us to quantify, for the first time, the reduction in bubble size in a three-phase flotation system and the improvement in froth stability due to the use of a stator, and thus the enhancement in flotation performance. An inverse relationship is found between the pulp bubble size and froth stability. It is shown that the impeller designs that exhibited smaller bubble sizes resulted in higher froth stability values and also higher flotation recoveries. These findings provide insights into the links between pulp and froth zone phenomena, paving the way for improvements in flotation tank design that lead towards flotation optimisation.

中文翻译：

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叶轮-定子设计对气泡尺寸的影响：对泡沫稳定性和浮选性能的影响

摘要 机械浮选槽中的叶轮在保持颗粒悬浮、分散和破碎气泡、促进颗粒-气泡碰撞等方面起着关键作用。然而，叶轮产生的湍流状态也会影响矿浆-泡沫界面，破坏泡沫下部区域的稳定性并影响整体浮选性能。然而，人们对纸浆区设计修改对泡沫的影响知之甚少，也没有得到充分研究。在这项工作中，我们研究了叶轮 - 定子设计对大型实验室规模浮选罐性能的影响。两种不同的叶轮设计（带定子和不带定子）在一系列空气流速下进行评估，以确定纸浆气泡大小、泡沫稳定性和冶金回收率的变化。结果使我们能够量化，首次在三相浮选系统中减小气泡尺寸并由于使用定子提高了泡沫稳定性，从而提高了浮选性能。在纸浆气泡尺寸和泡沫稳定性之间发现了反比关系。结果表明，显示出较小气泡尺寸的叶轮设计导致更高的泡沫稳定性值和更高的浮选回收率。这些发现为矿浆和泡沫区现象之间的联系提供了见解，为改进浮选罐设计以实现浮选优化铺平了道路。在纸浆气泡尺寸和泡沫稳定性之间发现了反比关系。结果表明，显示出较小气泡尺寸的叶轮设计导致更高的泡沫稳定性值和更高的浮选回收率。这些发现提供了对纸浆和泡沫区现象之间联系的见解，为改进浮选罐设计以实现浮选优化铺平了道路。在纸浆气泡尺寸和泡沫稳定性之间发现了反比关系。结果表明，显示出较小气泡尺寸的叶轮设计导致更高的泡沫稳定性值和更高的浮选回收率。这些发现提供了对纸浆和泡沫区现象之间联系的见解，为改进浮选罐设计以实现浮选优化铺平了道路。