Yin Zixin, Peng Yuxing, Zhu Zhencai, Yu Zhangfa, Li Tongqing
School of Mechatronic Engineering, China University of Mining & Technology, Xuzhou, 221116 China.
Jiangsu Key Laboratory of Mine Mechanical and Electrical Equipment, China University of Mining & Technology, Xuzhou 221116, China.
Materials (Basel). 2017 Jul 31;10(8):882. doi: 10.3390/ma10080882.
The impact behavior between the charge and lifter has significant effect to address the mill processing, and is affected by various factors including mill speed, mill filling, lifter height and media shape. To investigate the multi-body impact load behavior, a series of experiments and Discrete Element Method (DEM) simulations were performed on a laboratory-scale mill, in order to improve the grinding efficiency and prolong the life of the lifter. DEM simulation hitherto has been extensively applied as a leading tool to describe diverse issues in granular processes. The research results shown as follows: The semi-empirical power draw of Bond model in this paper does not apply very satisfactorily for the ball mills, while the power draw determined by DEM simulation show a good approximation for the measured power draw. Besides, the impact force on the lifter was affected by mill speed, grinding media filling, lifter height and iron ore particle. The maximum percent of the impact force between 600 and 1400 N is at 70-80% of critical speed. The impact force can be only above 1400 N at the grinding media filling of 20%, and the maximum percent of impact force between 200 and 1400 N is obtained at the grinding media filling of 20%. The percent of impact force ranging from 0 to 200 N decreases with the increase of lifter height. However, this perfect will increase above 200 N. The impact force will decrease when the iron ore particles are added. Additionally, for the 80% of critical speed, the measured power draw has a maximum value. Increasing the grinding media filling increases the power draw and increasing the lifter height does not lead to any variation in power draw.
研磨体与提升板之间的碰撞行为对磨机的粉磨过程有显著影响，且受多种因素影响，包括磨机转速、磨机填充率、提升板高度和研磨介质形状。为了研究多体碰撞载荷行为，在实验室规模的磨机上进行了一系列实验和离散元法（DEM）模拟，以提高粉磨效率并延长提升板的使用寿命。迄今为止，DEM模拟已被广泛用作描述颗粒过程中各种问题的主要工具。研究结果如下：本文中邦德模型的半经验功率消耗对球磨机的适用性不太令人满意，而通过DEM模拟确定的功率消耗与实测功率消耗显示出良好的近似性。此外，提升板上的冲击力受磨机转速、研磨介质填充率、提升板高度和铁矿石颗粒的影响。冲击力在600至1400N之间的最大占比出现在临界转速的70 - 80%处。只有在研磨介质填充率为20%时，冲击力才能超过1400N，且在研磨介质填充率为20%时可获得200至1400N之间冲击力的最大占比。冲击力在0至200N范围内的占比随提升板高度的增加而降低。然而，超过200N时这一占比会增加。添加铁矿石颗粒时冲击力会降低。此外，对于临界转速的80%，实测功率消耗有最大值。增加研磨介质填充率会增加功率消耗，而增加提升板高度不会导致功率消耗有任何变化。
