Wet Grinding of Coal in the Szego Mill: Limiting Predictions and Experimental Results

Results from a systematic grinding study with the SM-320 Szego Mill are reported. A wide range of flow rates, from 750 to 5300 kg/h of coal, at 60-65% solids concentration has been covered, with both single and multiple passes through the mill. Particle size distributions and power consumption have been measured. Data, including those for energy consumption, have been correlated in terms of the mass fraction of particles passing various mesh sizes 45 μm and up.A dynamic wet-grinding model recently developed for the Szego Mill is reviewed. Use of this model allows a priori predictions of limiting performance for all design and operating variables in the "paste grinding" regime, i.e., at relatively high solids concentrations which are optimal for wet grinding in the Szego Mill. Limiting size predictions for the SM-320 mill and the conditions used are presented along with an initial attempt to incorporate the breakage function in the model. Predictions confirm the observed effects of feed rate and number of passes of material through the mill