An empirical model for entrainment in industrial flotation plants

Savassi, O.N.; Alexander, D.J.; Franzidis, J.-P.; Manlapig, E.

doi:10.1016/s0892-6875(98)00003-x

Cited by 138 publications

(81 citation statements)

References 11 publications

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“…7, and it follows a similar trend with mass recovery. Gangue flotation through entrainment has been known to be proportional to water recovery ( [Engelbrecht and Woodburn, 1975], [Kirjavainen, 1996] and [Savassi et al, 1998]). The correlation between mass and water recoveries suggests that higher gangue recoveries were more likely to be due to entrainment than poor selectivity.…”

Section: Effect Of Sibx/c12 Ttc Mixtures On Auriferous Pyrite Flotationmentioning

confidence: 99%

The flotation of auriferous pyrite with a mixture of collectors

Makanza¹,

Vermaak²,

Davidtz³

2008

International Journal of Mineral Processing

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Dithiocarbonates (xanthates) have been the most widely used collectors in sulphide mineral flotation. More recently, research has resulted in the use of trithiocarbonate (TTC) collectors. The present study focuses on the effect of mixtures of C 12 trithiocarbonate (C 12 TTC) and sodium iso-butyl xanthate (SIBX) in the flotation of auriferous pyrite and the associated gold and uranium from cyanidation tailings.Improved gold and uranium flotation responses were observed with collector mixtures than with SIBX alone. Sulphur recoveries were not affected. Mineralogical analysis of flotation concentrates showed that gold and uranium were also hosted by kerogen. It was therefore proposed that the improved recoveries could have been mostly due to higher kerogen recovery rather than synergism in pyrite flotation. This mechanism opens possibilities into maximising uranium recoveries in auriferous flotation circuits where low recoveries are common.

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Section: Effect Of Sibx/c12 Ttc Mixtures On Auriferous Pyrite Flotationmentioning

confidence: 99%

The flotation of auriferous pyrite with a mixture of collectors

Makanza¹,

Vermaak²,

Davidtz³

2008

International Journal of Mineral Processing

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“…Using the method by Savassi (1998) and Savassi, et al (1998) this recovery by entrainment ( ) can be calculated as follows:…”

Section: Predicting the Flotation Behaviour Of Composite Particlesmentioning

confidence: 99%

“…In equation (17), represents recovery by entrainment, the recovery of water to the concentrate, the overall recovery of a specific mineral, and the degree of entrainment, defined as the ratio of the recovery of fully liberated, hydrophilic gangue (such as quartz in a sulfide system) to water recovery (Savassi, 1998;Savassi, et al, 1998).…”

Section: Predicting the Flotation Behaviour Of Composite Particlesmentioning

confidence: 99%

The effect of mineral grain textures at particle surfaces on flotation response

Vos¹

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This research investigates the contribution of the spatial arrangement of hydrophobic mineral grains at particles surface towards their flotation response and its implications for forecasting flotation response. The approach taken was to estimate this grain textural characteristic from particle sections and to identify how it affected the overall rougher and scavenger copper mineral flotation recovery from two industrial copper flotation circuits.For the second circuit the overall rougher flotation kinetic parameters for the copper mineral were also evaluated.The first contribution of this work is the demonstration that a novel textural indicator is relevant to understanding the contribution of exposed mineral grain texture on the flotation process. It is the first mineral grain textural indicator that considers both the size of the grains and the degree to which they are dispersed at the particle surface. When the indicator was applied to particle sections from flotation feed, concentrate and tail samples from two industrial copper flotation circuits, it was shown, for the first time, with confidence that while particle size and perimeter composition affect particle flotation response the spatial arrangement of the copper mineral grains at the particle surface plays a key role.For the iron-oxide-copper-gold ore, copper mineral grains in complex texture classes produced statistically higher overall rougher recoveries for the 0-20% perimeter composition class. Chalcopyrite grains in complex texture classes in the copper porphyry ore produced higher overall rougher and scavenger recoveries for the 20-40% perimeter composition class. For the 0-20% perimeter composition class statistically meaningful differences were observed for the +106 m size class. It was shown that the higher overall recoveries for the complex texture classes in this case were due to increases in the overall rougher rate of flotation, the proportions of recoverable chalcopyrite in the feed or both. For both ores the largest proportions of copper mineral within complex perimeter texture classes were within coarse particles and complex textures were less common when particle perimeters comprised more than 40% of the copper minerals. This demonstrated that in order to study the impact of this textural characteristic for the two ores it must be done within well-defined particle size and perimeter composition classes, an important outcome that has not been reported in the current literature.The second contribution is a three-step method for evaluating the flotation response of copper minerals within different grain texture classes namely; particle perimeter texture II estimation, determining coefficients of variation in the mass proportions of the target mineral within perimeter texture-composition classes and mass reconciliation and recovery calculations. Another key contribution is in applying the bootstrap resampling technique to estimate these coefficients. This demonstrated the sensitivity of seemingly feasible perimeter texture-compos...

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“…Gorain et al (1998) showed that there is a relationship between froth recovery and froth retention time; and Mathe et al (2000) further developed this relationship. Four different methods have been proposed for measuring froth recovery in an industrial flotation plant: the changing froth depth technique (Feteris et al, 1987, Vera et al, 1999b; the mass balance technique (Savassi et al, 1997, Alexander et al, 2003; the direct measurement of bubble loading which is then used to calculate froth recovery (Savassi et al, 1997, Seaman et al, 2004; and the measurement of froth dropback which enables calculation of froth recovery (Rahman et al, 2013). All these models and methods will be discussed below.…”

Section: Figure 2mentioning

confidence: 99%

“…The principles and limitations of these methods are summarised in Bubble loading (Savassi et al, 1997, Seaman et al, 2004, Yianatos et al, 2008 A device is used to collect samples of bubble-particle aggregates rising towards the pulp froth interface, from which bubble loading may be calculated.…”

Section: Measurement Of Froth Recoverymentioning

confidence: 99%

An investigation of flotation froth rheology

Li¹

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Flotation froth is of significant importance because it ultimately determines overall flotation performance. Froth recovery, the fraction of valuable minerals coming into the froth phase which survive and report to the concentrate, has been widely used to evaluate the efficiency of transporting the valuable minerals from the pulp-froth interface to the concentrate launder.Froth recovery is related to the time that particles spend in the froth and the rate at which bubbles burst.It is believed that froth rheology has an impact on froth recovery in flotation. A more viscous froth should resist motion towards the lip, rising vertically before overflowing into the cell launder, resulting in significantly higher froth residence times and increased probability of froth drop back as well as froth collapse. Very little work has been done to study the rheology of a highly mineralised flotation froth and how it impacts on froth recovery. Therefore, this project aims to gain an insight into the correlations between froth properties, froth rheology and flotation performance.To achieve this goal, a novel method to measure froth rheology properly was developed in this project. The method involves the use of a rotating vane surrounded by a tube. The tube is required to minimise the adverse effects of the horizontal flow on the measurement.Equations have been provided to convert the vane rotational speed and measured torque to shear rate and shear stress, depending on whether the froth within the tube is fully or partially sheared.In order to investigate the correlation between froth rheology and froth properties, flotation tests were performed in a 20 L continuous flotation cell using a synthetic ore which was a mixture of chalcopyrite and silica. The flotation tests, conducted under different flotation conditions (i.e. air rate, froth depth, impeller speed, feed grade and feed P80), resulted in significant changes in the froth properties and the viscosity of the froth. The froth was shown to be shear thinning with minor yield stress. It could be modelled using a power-law model with the consistency index of this function being able to be used to represent the degree of viscosity of the froth phase.The observed change in the froth viscosity was shown to be largely a function of the change in the bubble size and the percentage of the bubble surface covered by particles. Smaller bubbles and a greater coverage of particles on the bubble surface result in a greater resistance to froth motion. Thus changes in cell operation which reduce the froth bubble size (e.g. higher impeller speeds, higher frother dosage rates) will result in a more viscous froth. Higher feed grades and a smaller particle size which result in a greater proportion of bubble surface coverage will also result in higher froth viscosities.A model was proposed which relates the apparent viscosity of the froth to the shear rate, the froth bubble size, the gas volume fraction in the froth, the percentage of the bubble surface covered by particles and a fittabl...

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An empirical model for entrainment in industrial flotation plants

Cited by 138 publications

References 11 publications

The flotation of auriferous pyrite with a mixture of collectors

The flotation of auriferous pyrite with a mixture of collectors

The effect of mineral grain textures at particle surfaces on flotation response

An investigation of flotation froth rheology

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