A modeling approach using back-calculated induction times to predict recoveries in flotation

Abstract

The current modeling flotation approach of the Julius Kruttschnitt Mineral Research Centre (JKMRC) predicts recoveries in a flotation circuit using a lumped parameter called the floatability of mineral particles (P) which has no direct physical meaning and is assumed to be conserved in flotation circuits in the absence of regrinding or change in chemical environment. In this paper, the original definition of P as the efficiency of collection was resurrected. Fundamental models of particle collection by bubbles were applied to an industrial data set from a down-the-bank flotation survey of the first four cells of the galena rougher circuit at BHP Billiton's Cannington operation in Australia. The floatability of mineral particles P was no longer treated as a lumped parameter but described by the physical measurable inputs of the models. Induction time as a model parameter was back-calculated from knowledge of the experimental data and application of the collection model. The assumption that the induction time of a size-by-liberation class at fixed chemistry was conserved allowed prediction of galena recoveries in the circuit. An extensive error analysis was conducted on the new modeling approach and it was found to be very sensitive to the value of the bubble rise velocity. Finally, since the variation in the key flotation variables down the bank at the BHP Billiton Cannington's lead rougher circuit was not significant, the two approaches predicted similar flotation kinetics down the bank.