Impact Load Behavior between Different Charge and Lifter in a Laboratory-Scale Mill.

Zixin Yin,Yuxing Peng,Tongqing Li,Zhangfa Yu,Zhencai Zhu

doi:10.3390/ma10080882

Abstract

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.

Highlights

A ball mill (Figure 1) is the key piece of equipment for secondary grinding after crushing and is suitable for grinding all types of ores and other materials
The results showed that increasing the lifter height and number of lifters results in larger number of lifters results inetlarger impact
(5–30%), lifter height (10–20 mm) and grinding media shape on impact we primarily studied the effects of mill speed (50–100% of critical speed), grinding media filling

Summary

Introduction

A ball mill (Figure 1) is the key piece of equipment for secondary grinding after crushing and is suitable for grinding all types of ores and other materials. The comminution process is dependent on the rotation of the mill to lift the grinding media for reducing particle size, including abrasion, crushing and impacting. For ball mills, it is dependent on the rotation of the mill shell for lifting the grinding media to. Mills, it is dependent the rotation the millparticle shell for lifting theare grinding media to impact and the mill on shell, grindingofmedia, and lifter contents of the impact the particle, and the mill shell, grinding media, particle and lifter are contents of the grinding grinding environment [5,6]. The grinding efficiency is affected by operating variables, such as the environment grindingparameter

Methods

Results

Conclusion