Grain-size distribution of starting sample of size class -3.35 mm: Reliability factor of the Bond work index of grindability

Abstract

The investigation of the Bond' work index of grindability of low-grade and high-grade copper ore from the Copper Mine Bor has given two, for the theory and practice of comminution processes, significant results. The first confirms the previous theoretical and practical experiences on these raw materials, which is slightly higher fragmentation resistance of low-grade copper ore, compared to high-grade copper ore Wi p=14.11 kWh/t and Wi rs=13.35 kWh/t, respectively. The second result indicates the effect of grain-size distribution of starting sample, size class -3.35 mm, for determination the Bond' work index -3.35 mm size class, on the values of Bond work index, Wi r=14.11 kWh/t and Wi rs=13.35 kWh/t. The slight difference in resistance to fragmentation of tested copper ore samples gave the possibility of common processing of these raw materials. The stated effect of grain-size distribution of starting sample on the value of Bond work index, has a theoretical as well as a practical significance in designing and selection of process equipment in the grinding process. The grinding kinetics of low-grade and highgrade copper ore, as well as different times, required to obtain the grinding products of certain fineness confirm the previous statement.