A STUDY ON THE SPECIFIC RATE OF BREAKAGE OF IRON ORE OF SANGAN MINE IN A LABORATORY BALL MILL

Abstract: The specific rate of breakage is one of the most important factors in evaluation of grinding process especially in ball mill. In this article the effect of ball size and feed size on selection function were investigated using batch grinding circuit on two-iron ore anomaly (B, C) from sangan mine in north of Iran. Eight different monosize fractions were prepared between 2000 and 500 microns, using a 2 sieve series. The specific rates of breakage (Si) were determined from the size distributions at different grinding times, and the specific rates of breakage were compared for three different ball diameters (25.4, 16.6 and 9.6 mm). The results showed that the breakage function of both anomalies is normalizable (independent to the particle size) and it is independent to the ball size. But the specific rate of breakage variate with feed size and ball size. Also optimum size of balls for grinding of this feed obtained to be between 9.6-16.6mm.