Estimation methodology for Bond ball mill work index experiment output via mathematical modeling

The Frederick C. Bond has several grinding indices (ball, rod, abrasion), one of which has been a significant guide for ball mills. The Bond ball mill work index is an expression of the material’s resistance to ground and a measure of the grinding efficiency. The test is a standardized methodology that ends when a circulating load of 250% is obtained. In this paper, a new method based on the Population Balance Model (PBM) is proposed and validated to estimate the results of the Bond ball mill work index test (WiB). The model presented in this study combines the first cycle of the Work Index test (at 250% circulating load) with the PBM. Impure limestone, fluorite, chalcopyrite, and hematite ores were used to run both tests with a good confidence level (SSE less than 0.4 in all samples tested). As stated, based on the methodology the operational parameters for grinding (charge level, ball size distribution, and critical speed) were kept constant. The methodology developed showed great simplicity and potential applicability to a wide range of minerals by carrying out only one grinding test and numerical iteration to obtain a 250% circulating load.