Variations in the induction period for particle-bubble attachment
Variations in the induction period for particle-bubble attachment
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DOI：
10.1016/j.mineng.2012.03.034
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发表时间：
2012-10
影响因子：
4.8
通讯作者：
D. I. Verrelli;P. Koh;W. Bruckard;M. Schwarz
中科院分区：
文献类型：
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作者：
D. I. Verrelli;P. Koh;W. Bruckard;M. Schwarz
浮选的成功取决于颗粒-气泡的附着。预测附着的一个方便的方法是比较滑动“接触”的持续时间和诱导时间。而一些理论模型和经验的相关性存在评估的“滑动接触”的时间，相对较少的是已知的感应时间的关键决定因素。对于给定物理化学环境中的给定颗粒类型，通常将诱导时间视为常数。最近使用CSIRO Milli-Timer的测量结果表明，不仅滑动时间存在相当大的变化，甚至个别“理想”颗粒分数的诱导时间也存在相当大的变化。特别地，考虑对颗粒的接近轨迹的依赖性是相关的，其可以根据颗粒与气泡的第一近端接触的极角来量化。我们的数值模拟，它严格地描述了微流体力学，并预测诱导期大幅增加，增加极角的冲击，强烈支持这一假设。我们还观察到邻近粒子对接近粒子的附着的影响;这些多体相互作用，在大多数理论模型中没有考虑，可以足以刺激附着。
The success of flotation is governed by particle–bubble attachment. A convenient means of predicting the attachment compares the duration of sliding ‘contact’ with the induction time. Whereas a number of theoretical models and empirical correlations exist for evaluating the ‘sliding contact’ time, comparatively little is known about the key determinants of induction time. It is usual to take the induction time as a constant for a given particle type in a given physicochemical environment. Recent measurements using the CSIRO Milli-Timer suggest considerable variation not just of sliding times, but even of induction times for individual ‘ideal’ particle fractions. In particular, it is relevant to consider dependence on the approach trajectory of the particle, which can be quantified in terms of the polar angle of first proximal contact of the particle with the bubble. This hypothesis is strongly supported by our numerical modelling, which rigorously describes the microhydrodynamics, and predicts substantial increase in induction period with increasing polar angle of impingement. We also observe the influence of neighbouring particles on the attachment of an approaching particle; these multi-body interactions, which are not considered in the majority of theoretical models, can be sufficient to stimulate attachment.