An analysis of ball-and-race milling part III. Scale-up to industrial mills

The scale-up of breakage parameters measured in the Hardgrove mill to large mill diameters, using a simulation model for continuous milling, is discussed. Mill capacity for race diameter D in meters is where QH is mill capacity determined by the model for the Hardgrove mill. The total mill power at normal grinding conditions for coal is where ηm is motor efficiency. The variations in fineness of grind with mill capacity, Hardgrove Grindability Index, classifier setting, and air—coal ratio are described. Results from an E1.7 mill agree with model predictions.