Simulation of the breakage of bonded agglomerates in a ball mill

Size reduction is an essential operation across many industries. Despite its prevalence, the efficiency of the conversion of applied force to the creation of new surfaces is extremely poor, none worse than the commonly encountered ball mill. However, tuning of operational parameters may be a means to increase the low efficiency levels, if the proper connection between operating conditions and breakage conditions can be determined. Described here is the implementation of the Bonded Particle Model (BPM) within the Discrete Element Method (DEM) framework to analyze the breakage of bonded agglomerates within a batch ball mill. The effect of agglomerate bond strength (σ¯max), grinding media diameter (dm), grinding media fill level (J) and drum rotation rate (ϕc) on breakage and flow is analyzed using the Attainable Region (AR) approach. It is found that agglomerate strength and grinding media diameter affect breakage significantly, whereas grinding media fill level has a minor affect. Drum rotation rate has potential as a control parameter for fine tuning of the breakage behavior. The majority of breakage occurs near the mill shell, rather than at the point of impact between the media and material and the extent of material breakage has a significant influence on the material flow within the mill. Our work demonstrates that computational simulation is a powerful tool for analyzing the flow and breakage in ball mills and can aid in decision-making for more efficient operation.

Here we explore the important topic of breakage in a batch mill through numerical simulation. We investigate the effect of important operational parameters, matching well with previously reported experimental results. Our results show that numerical simulation is a promising route to developing more efficient size reduction technologies.Figure optionsDownload as PowerPoint slideHighlights
► Numerically investigated agglomerate breakage in batch ball mill.
► Parametric investigation of milling behavior.
► Range from little breakage to complete breakage with variation in bond strength.
► Duplicate experimental trends with rotation rate and grinding media diameter.
► Breakage occurs near the mill shell, a key result for more efficient mill design.