浮选过程中颗粒-气泡黏附作用机理及研究进展

Mechanism and research progress of the bubble-particle attachment in flotation

系统分析总结了浮选过程中颗粒与气泡的黏附概率模型、EDLVO理论、颗粒-气泡集合体的受力分析、影响因素分析和颗粒-气泡黏附的研究进展.基于接触时间、感应时间的方法和能量势垒的方法,分别从动力学和热力学的角度分析总结了黏附概率模型,并从动力学和热力学的角度解释了颗粒大小、气泡大小、颗粒疏水性、颗粒表面粗糙度和溶液p H对黏附概率的影响,对静态环境和湍流环境中颗粒-气泡集合体进行了受力分析,颗粒和气泡的黏附力有毛细作用力、液体静压力和浮力,静态环境中的脱附力只有重力,但是湍流环境中的脱附力还包括振荡力和离心力.很多研究学者利用先进的仪器和检测手段对颗粒-气泡的黏附做了大量的研究,取得了大量研究成果.颗粒-气泡黏附作用过程相当复杂,试验研究时简化了作用条件,目前理论不能满意解释黏附过程,需要结合实际进行更深层次、更全面的研究.

The interaction process between particles and bubbles can be classified as collision,attachment,and detachment;all three sub-processes determine the collection probability between particles and bubbles.Upon collision,the hydrophobic particles strongly attach to the rising air bubbles,which carry them to the surface,thereby overflowing the flotation cell in the collecting launder. Hydrophilic particles unattached to the rising air bubbles are left to settle at the bottom of the cell to be discharged.Whether the target mineral particles can attach to the rising air bubbles is the key to froth flotation.Therefore,studying bubble-particle attachment to improve the flotation efficiency is quite significant.The bubble-particle attachment probability model,EDLVO theory,force analysis of the bubble-particle aggregate,influence factors,and experimental progress of the bubble-particle attachment were systematically analyzed.Based on the methods of contact time,induction time,and energy barrier,the adhesion probability model was analyzed from the perspectives of dynamics and thermodynamics,and the effect of particle size,bubble size,particle hydrophobicity,particle surface roughness,and pH values on adhesion probability were explained.The force analysis of the bubble-particle aggregate under quiescent and turbulent conditions was conducted.Typically,there exist three types of attachment forces of the bubble-particle aggregate :capillary force,hydrostatic pressure force,and buoyancy force.The weight force is the only detachment force of the bubble-particle aggregate in the quiescent condition,but the vibration and centrifugal forces are also detachment forces in the turbulent condition.Many researchers have conducted substantial research on particle-bubble adhesion using advanced instruments and detection means,and have made several research achievements.However,because bubble-particle interaction is extremely complicated,the interaction conditions are simplified during experimental study.Therefore,.the attachment process is not satisfactorily described by the available theory.Combined with practical application demands,a bubble-particle study should be conducted from a deeper and more comprehensive level.