Abstract: Wet ball mill is a widely used grinding equipment in industrial production,and its operating cost accounts for about 50% of the total cost of the mineral processing plant. Improving grinding efficiency holds significant positive implications for energy saving and efficiency enhancement in mineral processing plants. In order to better understand the influence of grinding process parameters on grinding efficiency and thereby better guide industrial production,a discrete element method (DEM) analysis of the grinding effect in a wet ball mill based on fluid-solid coupling is carried out. The study takes the ϕ2. 7 m×4 m wet ball mill as the research object. A gas-liquid-solid three-phase flow coupling model within the mill is established using the DEM-VOF method,and the movement state of the materials and the collision energy utilization rate under different slurry concentrations are analyzed. The results showed that the grinding effect is closely related to slurry concentration. When the slurry concentration is low,particles in the dead zone account for a higher proportion,resulting in reduced grinding efficiency. With increasing slurry concentration,the material flow state significantly improves and stabilizes,leading to increased grinding efficiency. When the slurry concentration is 90%,the total collision energy inside the mill reaches its peak value;However,the energy utilization rate of this collision energy is not the highest. In contrast,at a slurry concentration of 80%,the energy utilization rate is the highest. The total collision energy under this concentration is close to that at 90% concentration and is significantly higher than under the other three tested grinding concentrations. Considering comprehensive grinding efficiency alongside liner plate and grinding media wear,a slurry concentration of 80% is deemed appropriate. Collisions between grinding media and ore inside the mill are dominated by low energy levels,indicating that ore breakage relies primarily on the cumulative effect of multiple impacts. Simultaneously,tangential collision energy is higher than normal collision energy,signifying that ore breakage inside the ball mill is dominated by the abrasive stripping effect. 

Key words: wet ball mill,fluid-structure interaction,discrete element method,slurry concentration,grinding effect