Mechanistic modeling and simulation of a batch vertical stirred mill

Vertical stirred mills are now widely used in the minerals industry and the increasing variety of models from different manufacturers and number of new units installed worldwide are evidence of the growing interest in them. With so many options available, it becomes ever more difficult at the design stage of a plant to choose the most appropriate mill for a given application. The present work takes advantage of a mechanistic mill model originally developed for ball mills and the discrete element method (DEM) to simulate breakage in a vertical stirred mill. Data from a batch mill, in which two materials were tested (copper ore and limestone), served as the basis for fitting selected material parameters, whereas the remainder were used as default. Mill power has then been predicted using the discrete element method and deviations smaller than 3.5% were found between predictions and measurements. On the basis of these, the model has demonstrated to provide valid predictions from comparisons to size distributions at a fixed grinding time for different stirred speeds and percentages of solids.