Role of in situ gas nucleation/hydrodynamic cavitation in fine particle flotation

细粒浮选回收矿物是采矿和矿业中公认的挑战，由于细粒与气泡的碰撞和附着效率低，以及主要由无意活化、泥浆覆盖和不可避免的机械夹带导致的泡沫质量差，往往导致回收率较低。在文献中，控制矿浆化学条件下的高强度搅拌(HIA)在改善细粒浮选方面取得了一些成功。然而，以往研究中缺乏合适的仪器设备，限制了对细粒浮选系统基础认识的进展。在最近的一项研究中，我们证明了溶解空气在促进疏水细颗粒的聚集和浮选方面发挥了关键作用。由于空气在环境条件下的溶解度有限，因此选择性细颗粒聚集的改善相当有限。为了充分利用溶解气体来改善细粒浮选，在HIA过程中用高溶解度气体(如CO2)饱和矿浆或设计一种可以连续向矿浆中引入空气或CO2的系统是非常可取的。概念和实践之间的关键差距是通过HIA在目标颗粒上原位选择性地产生足够数量的空泡。为了填补这一空白，有必要了解给定的HIA系统中的气体成核。

Flotation of fine particles for mineral recovery is a recognized challenge in mining and minerals industry, often leading to low recovery due to low collision and attachment efficiency of fine particles with air bubbles, and poor froth quality mainly by unintentional activation, slime coating and inevitable mechanical entrainment. In literature, high intensity agitation (HIA) under controlled pulp chemistry conditions has found some success for improving fine particle flotation. However, lack of suitable instrumentation in previous studies has limited the progress in fundamental understanding of fine particle flotation systems. In a recent study, we demonstrated that dissolved air played a key role in enhancing the aggregation of hydrophobized fine particles and hence their flotation. Due to limited solubility of air under ambient conditions, the improvement of selective fine particle aggregation was rather limited. To improve fine particle flotation by taking full advantage of dissolved gases, saturating the slurry with a gas of high solubility, such as CO2 or designing a system in which air or CO2 can be continuously introduced into the slurry during HIA is highly desirable. The key gap between the concept and practice is to generate a sufficient number of cavity bubbles in situ selectively on target particles by HIA. To fill this gap, it is essential to understand gas nucleation in a given HIA system.