RIVS Group, Saint-Petersburg, Russia

A. D. Samukov, Leading Production Engineer, A_Samukov@rivs.ru
S. I. Gerasimenko, Head of Ore Pretreatment Sector

Reduction of capital and operating costs, and improvement of selectivity of mineral dissociation assumes the use of autogenous milling process at mines. While being caved, ore forms some particles of high strength, which resist impacting and possess no sufficient mass for finer milling. Accumulated in a mill, such particles worsen the mill productivity and increase the energy inputs. One of the main ways to prevent accumulation of difficult-tomill fraction is to remove it from a mill for the re-grinding. Due to complexity of full-scale testing of autogenous milling in semi-commercial quantity, it is increasingly popular to use simulation modeling in JKSimMet, which provides an integrated mathematical model of a milling cycle based on the studies of the physical and mechanical properties of test ore. For the simulation modeling and analysis, we selected iron ore (ferruginous quartzite). The modeling results show that the irretrievable removal of –70 +24 mm size is limited due to overcrowding of the mill by the finer sizes (–24 +1 mm) and by the capacity of the outlet grating of the mill. For an autogenous mill with the drum of 7×2.3 m, the limitation made 24–26 % of the initial feed in the cycle. In re-grinding down to the size of –5 mm with return to the milling cycle, the limitation grows to 55–58 % owing to the reduced size of the circulating fraction to –5 +0.63 mm. Depending on the amount of the small sizes to be removed, and on the selected process flow chart, the autogenous mill capacity in terms of the initial feed can be increased 1.1–2 times. The implemented research proves the relevance and high efficiency of the autogenous milling enhancement method with removal of small sizes from the mills for the further pebble milling, for the return in the milling cycle after re-grinding.

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