丁世豪, 尹青临, 张友飞, 等. 浮选颗粒-气泡间脱附过程能量作用机制[J]. 煤炭学报, 2022, 47(7): 2817-2824.
引用本文: 丁世豪, 尹青临, 张友飞, 等. 浮选颗粒-气泡间脱附过程能量作用机制[J]. 煤炭学报, 2022, 47(7): 2817-2824.
DING Shihao, YIN Qinglin, ZHANG Youfei, et al. Energy mechanism of detachment between particle and bubble[J]. Journal of China Coal Society, 2022, 47(7): 2817-2824.
Citation: DING Shihao, YIN Qinglin, ZHANG Youfei, et al. Energy mechanism of detachment between particle and bubble[J]. Journal of China Coal Society, 2022, 47(7): 2817-2824.

浮选颗粒-气泡间脱附过程能量作用机制

Energy mechanism of detachment between particle and bubble

  • 摘要: 浮选颗粒-气泡间稳定性分析是浮选领域内的研究重点,传统脱附理论认为当颗粒所受外 力大于颗粒-气泡间最大黏附力时颗粒从气泡表面脱附,忽略了颗粒-气泡间气液固三相润湿周边 滑动收缩的动态过程,未考虑脱附力作用时间对脱附过程的影响。 为了完善浮选颗粒-气泡间脱 附理论,以单颗粒、单气泡为研究对象,采用黏附力测量仪测量颗粒-气泡间脱附过程的临界脱附 力和脱附能,并借助颗粒-气泡振动脱附观测系统观察颗粒-气泡在脱附过程中三相润湿周边滑动 收缩规律,最后从热力学角度出发提出了一种基于能量分析的颗粒-气泡间稳定性评判方法。 结 果表明:随着颗粒接触角的增加颗粒-气泡间稳定性增强,发生脱附时需要的临界脱附力和脱附能 增大。 颗粒-气泡间脱附能由气泡拉伸变形阶段的形变能和三相润湿周边滑动收缩阶段的滑动能 两部分组成,两部分能量均随颗粒接触角的增加而增加。 颗粒从气泡表面脱附一方面要求外力大 于颗粒-气泡间最大黏附力,另一方面还需外力作用足够时间以保证气液固三相润湿周边完成滑 动收缩。 从能量角度来看,颗粒-气泡间不受外力时可看作是一个处于平衡状态的热力学系统,当 外力做功小于脱附能时颗粒-气泡间通过气液、液固和气固界面面积的变化维持稳定;但当外力做 功大于脱附能时颗粒与气泡分离。

     

    Abstract: The stability analysis between particles and bubbles is the focus of research in the field of flotation. The traditional detachment theory holds that the particle detachment from the surface of the bubble when the external force on the particles is greater than the maximum adhesion force between the particles and bubbles. The dynamic process of the sliding shrinkage of the gasliquidsolid threephase contact line is ignored,and the effect of duration of detachment force on the detachment process is not considered. In order to improve the theory of particlebubble detachment in flotation,the critical detachment force and detachment energy of the particlebubble detachment process were measured by using an adhesion force tester,taking single particle and single bubble as research objects. Then the particlebubble vibration detachment observation system was used to observe the sliding shrinkage of threephase contact line during the detachment process. Finally,a new method for evaluating the stability between particles and bubbles based on energy analysis is proposed from the perspective of thermodynamics. The results show that the stability between particles and bubbles increases with the increase of particle contact angle,and the critical detachment force and detachment energy for detachment increase. The detachment energy between particle and bubble is composed of two parts:the deformation energy in the tensile deformation stage of bubbles and the sliding energy in the sliding contraction stage of the threephase contact perimeter,both of which increase with the increase of the particle contact angle. The detachment of particles from the surface of bubbles requires that the external force is greater than the maximum adhesion force between particles and bubbles,and on the other hand,sufficient time of the external force is required to complete the sliding contraction in the threephase contact line. From the perspective of energy,the particles and bubbles can be regarded as a thermodynamic system in equilibrium when there is no external force. When the work done by the external force is less than the detachment energy,the particles and bubbles remain stable through the changes in the interface area of gasliquid,liquidsolid and gassolid. However,when the work done by the external force is greater than the detachment energy,the particles and bubbles are completely separated.

     

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