EFFECT OF MILL FEED SIZE DISTRIBUTION AND GRINDING MEDIA SIZE ON SIZE REDUCTION PERFORMANCE OF AN INDUSTRIAL SCALE VIBRATING BALL MILL (VBM) IN CEMENT CLINKER GRINDING

In this study, open circuit single and two stage industrial scale vibrating ball mill (VBM) grinding performance of raw (uncrushed) cement clinker was investigated using different mill feed size distributions and grinding ball size configurations. The mill was modelled for the test cases using perfect mixing mathematical modelling approach. Different ball size configurations were applied in the grinding tests to estimate the effect of ball size configuration on grinding performance. Proposed coarse ball size configuration (30-20-15mm) was determined to increase the size reduction performance of single stage VBM grinding when coarse mill feed material was fed to the VBM (F50=185μm) as compared to the finer mill feed case (F50=24μm). VBM grinding performance was determined to increase with finer mill feed material (F50=24μm) and application of finer ball size configuration (10-8-6mm) in single stage grinding case as compared to the two stage grinding case.