Abstract:

In order to establish the impact breakage model of unconfined particle beds and improve the grinding efficiencies in ball mill, a study of nipped configuration of unconfined particle beds was carried out on the basis of the falling ball impact test. The influence of bed height, impact energy, impact velocity, ball size, and particle size on nipped configuration were analyzed by the falling ball impact test. Experimental results show that on the conditions of sufficient impact energy, the bed height of the nipped particles is the stack height with 2 layers particles. The nipped range has a significant relationship with the falling ball size and the nipped angle. Finally, a mathematical model was built to analyze the relationship among nipped range radius, ball size and angle of repose.

Key words:  falling ball impact, unconfined particle bed, nipped height；nipped range

摘要：

为提高球磨粉碎的效率，构建了球形介质对非限制料层的冲击粉碎模型，开展了落球冲击破碎下的料层夹持形态研究。通过石英砂料层的落球冲击破碎实验，分析了初始料层厚度、落球冲击能量、冲击速度、落球大小以及料层颗粒大小对料层夹持形态的影响。实验结果表明，夹持颗粒完全破碎时，料层夹持厚度为2层颗粒的堆叠厚度情况下，夹持范围受落球大小和夹持角度的影响较大。根据夹持角度与安息角的关联性，建立了料层夹持半径与落球大小、安息角的数学模型。

关键词: 落球冲击, 非限制料层, 夹持厚度, 夹持范围