Reducing uncertainty in mineral flotation—flotation rate constant prediction for particles in an operating plant ore

Ralston, John; Fornasiero, Daniel; Grano, S.R.; Duan, Jinming; Akroyd, T.

doi:10.1016/j.minpro.2006.08.010

Cited by 63 publications

(57 citation statements)

References 16 publications

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“…In order to get an idea of the range of shear rates experienced in a froth, the maximum froth shear rates calculated in all conducted tests have been plotted in Figure 6. It can be seen that the maximum froth shear rate is less than 4 s -1 in all 33 tests, which is much smaller than the mean shear rate in the pulp phase that can be up to 90 s -1 [23].…”

Section: Accepted M Manuscriptmentioning

confidence: 76%

Determining the significance of flotation variables on froth rheology using a central composite rotatable design

Farrokhpay

Runge

et al. 2016

Powder Technology

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Determining the significance of flotation variables on froth rheology using a central composite rotatable design, Powder Technology (2015Technology ( ), doi: 10.1016Technology ( /j.powtec.2015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractFroth performance in a flotation cell is expected to be affected by froth rheology due to change in the froth transportation rate. However, very little study has been performed to investigate how froth rheology responds to flotation variables. This paper presents an experimental program performed to study the effects of flotation variables (i.e. feed grade, feed particle size, froth height, superficial gas velocity and impeller speed) on the froth rheology. These conditions were varied using a central composite rotatable design (CCRD).

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Section: Accepted M Manuscriptmentioning

confidence: 76%

Determining the significance of flotation variables on froth rheology using a central composite rotatable design

Farrokhpay

Runge

et al. 2016

Powder Technology

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“…It can be seen that in all 33 tests the maximum froth shear rate is less than 4 s -1 , which is much smaller than the mean shear rate in the pulp phase, which can be up to 90 s -1 (Ralston et al, 2007). In the subsequent work, it was decided to concentrate analysis on that portion of the froth rheogram below 5 s -1 .…”

Section: Froth Rheology Measurement Resultsmentioning

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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“…A better understanding of the role of the texture of exposed hydrophobic grains -referring to their spatial arrangement -will help build the link between the empirical floatability component modelling approach (Runge, 2007;Harris, et al, 2002;Amelunxen & Amelunxen, 2009a;Amelunxen & Amelunxen, 2009b;Hay & Rule, 2003; and property-based flotation modelling (Grano, 2006;Ralston, et al, 2007;Evans, 2010;Bushell, 2012;Ford, et al, 2011;Yoon, et al, 2012). As such the aim of this thesis is to determine the impact of particle surface grain textures on flotation performance and the implications for forecasting flotation performance.…”

Section: Scope Of the Thesis And Research Objectivesmentioning

confidence: 99%

“…Chemical effects may stem from the use of different flotation chemicals, the flotation gas used (Leja & Schulman, 1954;Leja, 1989;Laskowski, 1993;Kelebek, et al, 1996;Bradshaw, 1997;Bozkurt, et al, 1999;Comley, et al, 2002;Du Plessis, 2003;Moyo, 2005) as well as the galvanic interactions amongst reactive sulfide minerals (Imaizumi & Inoue, 1963;Sutherland, 1989;Yelloji & Natarajan, 1989;Yelloji & Natarajan, 1990;Trahar, et al, 1994;Ekmekci & Demirel, 1997) and reactive sulfides and the grinding media used during milling to produce fine particles (Iwasaki, et al, 1983Adam & Iwasaki, 1984Forssberg, et al, 1993. The mechanical factors that impact on froth flotation include the design and operation of the individual flotation machines (Arbiter & Harris, 1969;Arbiter & Harris, 1976;Newell & Grano, 2007a;Newell & Grano, 2007b;Ralston, et al, 2007) as well as the contribution of different flowsheet configurations (Alexander, et al, 2000;Alexander & Wigley, 2003;Schwarz & Kilgariff, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Of the latter, the overall composition of the exposed surface is the most widely studied feature and for composite particles the behaviour is frequently approximated by considering the behaviour of the mineral constituents of each particle surface, relative to their total proportions at the surface (Ralston, et al, 2007;Evans, 2010;Bushell, 2012;Ford, et al, 2011). The others -grain size, phase specific surface area (PSSA), intergrowth complexity and locking ratio -although known to affect the flotation process, are applied more as diagnostic parameters and have not found their place in property-…”

Section: Introductionmentioning

confidence: 99%

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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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Reducing uncertainty in mineral flotation—flotation rate constant prediction for particles in an operating plant ore

Cited by 63 publications

References 16 publications

Determining the significance of flotation variables on froth rheology using a central composite rotatable design

Determining the significance of flotation variables on froth rheology using a central composite rotatable design

An investigation of flotation froth rheology

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

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