Grinding of Itabirite Iron Ore in Autogenous and Semi-Autogenous Mills

Holistic Pre-Feasibility Study of Comminution Routes for a Brazilian Itabirite Ore

“…It is important to emphasize that the savings related to the absence of grinding media in Route #4 (Table 3) compensate economically for this high energy consumption. Route #3 presented an OPEx that is 11% higher than that of the conventional circuit (Route #1), which confirms estimates by Rodrigues [25] and might be explained, at least in part, by the higher energy consumption demanded by the SAG mill.…”

“…The single-particle breakage and the compressed bed breakage in HPGRs were described by the same DWT data for crushers, based on simplifications suggested by Daniel [24]. The SAG mill was sized, scaled up, and simulated in JKSimMet ® [18], based on a selected test in a pilot unit (1.8 m diameter mill) with a similar itabirite ore [12,25]. This equipment was scaled up by selecting the appropriate dimensions to process the designed throughput, using the specifications of a commercially available industrial unit.…”

“…This equipment was scaled up by selecting the appropriate dimensions to process the designed throughput, using the specifications of a commercially available industrial unit. As the SAG mill model in JKSimMet ® is limited for ores that are highly amenable to breakage, such as itabirites [25], the maximum discharge flow rate was verified using the model proposed by Latchireddi [26]. This model allows a more reliable estimation of the mill hold-up to avoid the slurry pooling phenomenon [16].…”

“…This model allows a more reliable estimation of the mill hold-up to avoid the slurry pooling phenomenon [16]. Regarding the total SAG mill load, it is suggested to adopt a value of 25%, given that the operational conditions of the industrial mills that served as a reference for the development of the model were close to this value [27], which was also adopted in the pilot tests performed by Rodrigues [25]. Primary cyclones were modeled and simulated using the efficiency curve model, and model parameters were obtained from an industrial cyclone efficiency curve for a similar ore [13].…”

“…The estimates were based on empirical equations for calculating the wear of liners and grinding media and, in some cases, on industrial data. Some of the assumptions on prices are based on the work by Rodrigues et al [12,25]: US$1.95/kg for grinding media, US$0.06M for crusher liner, US$2.3M for ball mill liner, and US$2.6M for SAG mill liner. In the case of wear of the HPGR, an estimate of cost published by Amelunxen and Meadows [42], corresponding to US$1.8M for each roll changeover, was used.…”