application of spi for modeling energy consumption in sarcheshmeh sag and ball mills

in this research, the efficiency of the comminution circuit as well as the efficiency of size classification equipment of the concentrator plant 2 of sarcheshmeh copper complex was studied. the comminution circuit of this plant includes one sag mill in a closed circuit with a vibrating screen and one ball mill with a size classification system of hydrocyclone. the goal of this work was to calculate the proportion of each of these mills at energy consumption and generating suitable product for flotation as a further process. three stages of sampling were performed and consumed energy was also modeled. the average efficiency of the initial ball mill was obtained which was equal to 72.96%. the average of the proportion of (consumed) energy by sag and ball mills from total consumed energy at mills, was 44.65% and 55.35% respectively. the proportion of sag and ball mills in producing the final product (particles finer than 74 µm) was 55.38% and 44.62% respectively. that is, the sag mill produces about 10.76% more than the ball mill in the final product. the average consumed energy at sag and ball mills to produce one ton of final product was 23.16 kwh/t and 36.05 kwh/t respectively. thus, the ball mill consumes 12.89 kwh/t, more energy than the sag mill in producing the final product. the average cyclones’ imperfection was 0.361 and therefore the average efficiency of cyclones’ separation was equal to 63.9% and the average efficiency of the vibrating screen was equal to 99.89%. as overflow of the initial cyclones (final product of comminution circuit) forms feed of rougher cells, cyclones’ inappropriate performance could severely influence the whole flotation process.