Vertical mill simulation applied to iron ores

The application of vertical mills in regrind circuits is consolidated. This type of mill is now attracting interest in primary grinding applications, due to its higher efficiency when compared to ball mills, which are usually used at this stage. In this study, a coarse sample of iron ore was tested in a pilot scale grinding circuit with a vertical mill. Other three samples of pellet feed had already been tested with the methodology used in this study. The sample of coarse iron ore was characterized in laboratory tests carried out in a small batch ball mill. Selection and breakage function parameters were determined from the laboratory tests. The parameters were then used for simulating the pilot scale tests using Modsim™ software. The model previously implemented in Modsim™ has been successfully applied to represent the vertical mill operated with different ores. The simulations produced particle size distributions that were very close to the actual size distributions, and the predictions were accomplished only by imputing the calibrated parameters from the batch tests, the power draw and the feed size distribution of the pilot tests. The methodology is therefore useful for scale-up and simulation of vertical mills, only requiring laboratory tests that can be carried out in standard laboratory batch ball mills with small amounts of samples.