煤颗粒与气泡黏附行为的试验研究

浮选微观模型认为,颗粒与气泡的黏附是实现浮选的关键步骤,对颗粒与气泡黏附规律的直接研究非常重要。采用自行设计搭建的颗粒与气泡碰撞、黏附行为测量装置,以内蒙古公乌素原煤为试验对象,直接观测了不同密度级的0.1~0.15 mm粒级煤样的黏附行为,并采用自行开发的多目标追踪软件进行分析。结果表明:煤颗粒在与气泡碰撞前会发生绕流,速度大小和方向均会改变,当煤颗粒与气泡碰撞时,煤颗粒的速度降为最低。煤颗粒在气泡表面的滑动速度先是逐渐增大,在气泡"赤道"位置处达到最大值,越过"赤道"后,煤颗粒的滑动速度逐渐减小,并最终黏附在气泡底部。煤颗粒与气泡的黏附效率随碰撞角的增大而降低,在碰撞角相同时,随煤样密度级的增大,黏附效率降低,临界黏附角减小。随煤颗粒沉降末速的增大,煤颗粒与气泡的黏附效率降低,临界黏附角减小。

Experimental study on the attachment behavior of coal particles and bubbles

The flotation microscopic model considers that the attachment behavior of coal particles and bubbles is the key step to achieve flotation.Therefore,the direct research on attachment behavior is very important.A device was designed by ourselves to directly measure the attachment behavior of coal particles and bubbles.In this paper,the raw coal of Inner Mongolia Gongwusu was taken as the experiment subjects and the attachment behavior of 0.1-0.15 mm coal samples with different densities was directly observed.Then,it was analised by the multi-target tracking software.The results showed that coal particles would flowed around the bubble before collision occurrence,and the velocity and direction of coal particles would changed.The velocity of coal particles decreased to minimum when coal particles colliding with bubble.The sliding velocity of coal particles on the bubble surface firstly increased gradually,and sliding velocity reached the maximum at the bubble “equator” position.After crossed the “equator”,the sliding velocity of coal particles gradually decreased,and finally coal particles attached to the bottom of the bubble.The attachment efficiency of coal particles and bubbles decreased with the increase of collision angle.At the same collision angle,the attachment efficiency and the critical attachment angle decreased with the increase of coal density.With the increase of terminal velocity,both the attachment efficiency and the critical attachment angle decreased.Therefore,the regulation of the attachment efficiency of different density was verified.