Effect of Feeding Rate on Comminution Products by Fractal Geometry

Effect of feeding rate of crushing product was investigated on product particles size distribution by fractal dimension. particle size distribution was calculated according to the cumulative weight of the particles relative to particles size. A comparison between results obtained by Rosin-Rammler distribution and ones obtained by fractal geometry was made by root mean square error (RMSE). Comminution of ore was performed by three jaw, cone and roll crushers, each fed by rates of 0.5, 1, 1.5, 2, 3, 4 and 4.5 kilogram per minute. Fractal dimension of products for jaw, cone and roll crushers were (from 2.18 to 2.32), (from 2.12 to 2.27), and (from 2.30 to 2.43) respectively. Smallness of fractal dimension by cone crusher is due to particles uniformity. Bigness of fractal dimension of roll crusher is due to limited range of particles granulation. Limitation range of particle granulation causes uniformity of product weight distribution. A 2 mm opening sieve was selected as a passing target sieve. Results show that by increasing feeding rate, amount of material passing through of target sieve is decreased. The RMSE obtained by fractal geometry for jaw, cone and roll crushers were (between 8.01 to 8.60), (between 3.50 to 4.17) and (between 0.83 to 2.62) respectively. These ones obtained by Rosin-Rammler distribution were (between 8.11 to 8.60), (between 4.50 to 4.93) and (between 3.91 to 7.91) respectively. A comparison of results obtained by these two methods reveals that fractal geometry is a better way to particle size distributions description.