Institute for Mineral and Energy Resources publications

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Browsing Institute for Mineral and Energy Resources publications by Author "CHEMECA (35th : 2007 : Melbourne, Australia)"

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    Froth stability as a performance indicator in sulphide minerals flotation plants
    (Engineers Australia, 2007) Zanin, M.; Wightman, E.; Grano, S.; CHEMECA (35th : 2007 : Melbourne, Australia)
    The implications of froth stability for recovery in mineral flotation are often underestimated. In the last years, technology and automation have been widely implemented in flotation plants, so that automatic level control and in-line visual analysis of the froth are now a standard feature in modern concentrators. However, most of the decision making process still relies on the operator's experience. The best flotation strategy is generally determined empirically, and froth stability, in particular, is rarely quantified. In this work, froth stability has been assessed, down the bank, in two different concentrators treating copper sulphide minerals. Froth stability was measured, in situ of the flotation cells, by the use of a transportable device (modified froth stability column), and other froth descriptors, like froth velocity and froth depth, were also measured. Differences in froth stability have been correlated to the different plant operating conditions, and implications on the recovery of minerals across the froth phase are discussed. It is shown that different flotation strategies may lead to similar metallurgical performance, and that froth stability can be a useful indicator to optimise operating conditions in the flotation cells.
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    Use of the foam drainage equation to model water flow in flotation froth
    (Engineers Australia, 2007) Randriamanjatosoa, L.; Zanin, M.; Grano, S.; CHEMECA (35th : 2007 : Melbourne, Australia)
    The standard foam drainage equation (Leonard and Lemlich, 1965; Goldfarb et al., 1988) was taken to model froth water flow in laboratory flotation column, using polypropylene glycols (PPG 425 and PPG 725) as frothers. Simulations were run to investigate the sensitivity of the model with respect to operating parameters. In the absence of particles, the model is in agreement with the experiments within a certain range of frother concentration; below and above which, it failed. Experimentally measured water flow rate was overestimated by the model at low and high frother concentration. Such discrepancies may be attributed to the assumptions accompanying the standard foam drainage equation. For instance, the model was modified to accommodate the effect of surface shear viscosity, which was measured using a deep channel surface shear viscometer. When plotted against frother concentration, surface shear viscosity follows the same trend as that of net water flow rate. It showed a maximum value within an intermediate range of frother concentration. The modified foam drainage equation that takes into account the interfacial properties of the gas-liquid interface significantly reduced the discrepancies between the model and experiment. However, a further improvement of the model is necessary to be applicable to three phase flowing froths in mineral processing industry.