Investigating the system flotation kinetics of fine chalcopyrite in a REFLUX™ flotation cell: Part II low-grade ores

Abstract

The flotation performance of the REFLUX™ Flotation Cell (RFC™) was assessed and quantified through a performance ratio relative to a bench scale mechanical cell. This new work extended the previous study (Parkes et al., 2022) on a model feed to cover two industrial low-grade chalcopyrite feeds, Feed A and Feed B, with Feed B containing a surface-active slime component. The initial phase of the work covered the sensitivity of the performance ratio to the changes in the process conditions in the mechanical cell, notably the gas flux and the feed pulp density. In general, the performance ratio was not very sensitive to the gas flux, mainly due to the need to prevent excessive entrainment which limited the applicable range of gas fluxes. Changes to the feed pulp density had a more significant effect on the performance ratio, hence it is recommended the performance ratio of the two systems be assessed at a similar feed pulp density. For both the low-grade ores, the performance of the RFC™, relative to the mechanical cell, was found to be very high. For Feed A, the performance ratio increased with the particle size, exceeding a value of 5 beyond a particle size of 10 µm. In general, a gas-to-feed flux ratio of 1:1 was found to be optimal. For Feed B, containing a surface-active slime component, the ratio typically exceeded a value of 10 and was less dependent on the particle size, pulp density and feed rate. Overall, the performance ratio increased as the feed pulp density decreased, suggesting a very strong improvement in the flotation kinetics within the RFCTM at lower pulp densities. While the selectivity of hydrophobic to hydrophilic material recovery was very high for Feed A, it was significantly reduced for Feed B, suggesting that the transport of the hydrophilic particles was assisted by the surface-active slime component in the feed.