(56g) Optimization of Breakage in a Ball Mill

Handling a mixture consisting of two or more solid components dissimilar in size is no easy task. Particles of varying size may react differently to identical processing conditions resulting in a blend consisting of regions lean in one component and rich in another. A common approach to minimize this segregation is to maintain a consistent particle size through processing of the material, and thus remove the size differences that tend to cause the components to segregate in the first place. An operation that is particularly useful at accomplishing this size ?standardization? is milling, which is regularly used in the food, mining, construction and pharmaceutical industries. However, despite its widespread use milling is a very crude operation, and adequate control and knowledge of the behavior inside the mill remains elusive and is the subject of much ongoing research.

In this work we present a systematic approach to optimize production of product falling within a specified size range, known as the Attainable Region (AR). Specific attention is paid to the total volume of grinding media inside the mill, the size of that media and the rotation rate of the mill and how each affects breakage within the mill. Suggestions are presented on how to reduce the overall time required to achieve the desired product as well as minimize the overall energy usage of the equipment. Finally, preliminary results from a DEM simulation including both charge motion and particle breakage are presented.