Entrainment of Particles into Flotation Froths

Smith, P. G.; Warren, L.J.

doi:10.1080/08827508908952647

Cited by 133 publications

(54 citation statements)

References 8 publications

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“…For such it is noticed, that small bubbles accumulate beneath the flock leading to a rise of the flock as a whole [11,17,35,36]. Step 1 to Step 2 illustrate the entrainment of fibres after bubble swarm theory by Smith and Warren [34]. Fibres are pushed into the froth by ascending bubbles.…”

Section: Particle Entrainment In Flotation Frothmentioning

confidence: 99%

“…In literature the following phenomena are used to explain the entrainment mechanism: (i) particle transport in the liquid film around the bubble, (ii) particle transport in the wake of rising bubbles, and (iii) bubble swarm theory. The bubble swarm theory after Smith and Warren [34] is illustrated in Figure 1, Step 1 to Step 2. It is assumed, that particles at the suspension froth interface (Step 1) are pushed in the froth (Step 2).…”

Section: Particle Entrainment In Flotation Frothmentioning

confidence: 99%

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Separation of cellulose fibres from pulp suspension by froth flotation fractionation

Redlinger-Pohn

Grabner

Zauner

et al. 2016

Separation and Purification Technology

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Flotation of cellulose pulp suspension in paper industry is primarily used for separation of ink particles from cellulose fibres. Entrainment, an unwanted phenomena well described in the field of mineral flotation, also leads to a removal of fibres with the flotation froth. We find that the entrainment phenomena can be used for the separation of long fibres from a fibre pulp suspension, and hence for pulp fractionation. Specifically, we use a 2D bubble column to investigate the influence of (i) bubble size, (ii) wash rate and (iii) stirring on the separation of long fibres from cellulose pulp suspension. Separation of fibres from fibre pulp suspension is tested for mechanical pulp and chemical pulp. We find that size selective recovery yields best result for (i) large bubbles, and (ii) additional washing due to the increase of small particle drainage. However, both strategies lead to a reduction of the total recovery rate. Stirring significantly improved the total recovery and benefited the selective separation. Best results are achieved with small bubbles for chemical pulp. For mechanical pulp, fractionation is more challenging due to lower froth stability, but still fibres with a reduced amount of smaller fraction can be recovered.

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Section: Particle Entrainment In Flotation Frothmentioning

confidence: 99%

Section: Particle Entrainment In Flotation Frothmentioning

confidence: 99%

Separation of cellulose fibres from pulp suspension by froth flotation fractionation

Redlinger-Pohn

Grabner

Zauner

et al. 2016

Separation and Purification Technology

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show abstract

“…may affect entrainment, however, particle size and froth stability are predominant (Smith and Warren, 1989). It has been found that coarse particles drain more readily from the voids between bubbles than fine particles.…”

Section: Effect Of Clay Minerals On Entrainmentmentioning

confidence: 99%

Mitigating the deleterious effect of clay minerals on copper flotation

Wang¹

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Clay minerals have a deleterious effect on the mineral flotation process. Generally, two major phenomena are observed in industry when processing high clay ores: no froth formed on the top of the pulp phase and few valuable minerals loaded on the top of froth. This is an ARC Linkage project with support from Pionera, a reagent company manufacturing biopolymers.The objective of the project is to define the different effects of clay minerals on copper flotation, and then to mitigate the deleterious effects of specific clay minerals in copper flotation by biopolymers and other means.In this research, two types of clay minerals, swelling bentonite with a 2:1 structure and nonswelling kaolinite Q38 with a 1:1 structure, were chosen to represent two typical kinds of clay minerals often seen in industrial flotation plants. The influence of bentonite and kaolinite on copper flotation was investigated. It was found that bentonite and kaolinite affected the copper flotation in a different way. Increasing the proportion of bentonite increased the pulp viscosity that reduced the amount of froth on the top of slurry and decreased flotation rate, resulting in a lower copper recovery. On the other hand, increasing the kaolinite content mainly decreased the copper grade by entrainment that is characterised by smaller bubble size and higher froth stability. The different roles of bentonite and kaolinite in the flotation were associated with their unique structure properties. Also, the collector and frother dosage plays an important role in specifying the different effect of bentonite and kaolinite on copper flotation performance.To mitigate the deleterious effect of kaolinite, three lignosulfonate biopolymers from Pionera, DP-1775, DP-1777 and DP-1778 with different structures, were examined. While rheological measurements indicated that these biopolymers dispersed the kaolinite aggregates, a beneficial effect of biopolymers on copper flotation in the presence of kaolinite was not observed. Instead, interactions of biopolymers with the frother appeared to enhance the froth stability and therefore further reduced copper grade by mechanical entrainment. Two-phase foam characterization revealed that the foam height increased in the blends of biopolymers with the frother. The dispersing and foaming abilities of biopolymers were governed by their structure features such as the content of functional groups, the molecular weight and counterions.The three biopolymers, DP-1775, DP-1777 and DP-1778, were also tested to reduce the negative effect of bentonite in copper flotation. Rheological measurements indicated that all of II the three biopolymers could not significantly reduce the pulp viscosity which was dictated by bentonite. This is consistent with the observation that none of the three biopolymers could enhance the copper recovery effectively. Electrolytes were then used to mitigate the deleterious effect of bentonite on copper flotation through reducing the high pulp viscosity.

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“…The recovery of particles by entrainment is strongly controlled by the recovery of water into the froth, the particle properties (e.g. size, shape, density), and the rheological properties of the pulp (Smith and Warren, 1989, Neethling and Cilliers, 2002, Vianna, 2004, Johnson, 2005b, Zheng et al, 2006, with higher water recoveries being indicative of a greater degree of entrainment.…”

Section: Entrainmentmentioning

confidence: 99%

Selective flotation of enargite from copper sulphides in complex ore systems

Tayebi-Khorami¹

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Recent research has demonstrated promising results showing the possibility of separating arseniccopper sulphides from other copper minerals by controlling the potential of the flotation pulp. Most of these studies were conducted on single mineral systems, and the selective removal of arseniccopper minerals in real ore systems is not well understood. In real ore systems, the efficiency of the separation strongly depends on the mineralogical characteristics of the ore samples. This study seeks to understand the effect of ore mineralogy on the floatability of enargite in a complex ore system, under a controlled potential flotation environment.A composite of several high arsenic-containing drill core intersections for the high arsenic sample (HAS) and a composite of some low arsenic-containing drill core intersections for the low arsenic sample (LAS) were selected from the Tampakan copper-gold deposit in the Philippines, providing a range of arsenic levels. Arsenic in the HAS sample (enargite) was practically twice that for the LAS sample. The non-enargite copper minerals (NECu) were mostly chalcopyrite and bornite in both samples.Comprehensive size-by-size, chemical and mineralogical analyses were performed on both ore samples. It was observed that the two ore samples had similar mineralogical characteristics in terms of mineral content and liberation distribution, however there are some differences in the proportions of minerals. It was also observed that NECu minerals were mostly distributed to the coarser size fractions, while the proportion of enargite in the finer size fractions was higher than for NECu. The mineral grain size data showed that enargite had the finest grain size distribution compared to other copper minerals.The selective separation of enargite from NECu minerals in a rougher flotation system under controlled pulp potential was investigated for both samples. It was observed that it is possible to selectively separate enargite from other copper minerals after reducing the pulp potential to about -200 mV SHE at pH 11 in the LAS sample. However, no separation between enargite and NECu minerals was observed at a reducing potential for the HAS sample, and enargite did not float very well for this sample as the Eh was changed.The Particle Kinetic Model was used to predict the flotation response of enargite and NECu in the HAS sample based on mineral flotation rates derived from the LAS sample and the mineralogy of the HAS sample. It was observed that the predicted values of enargite recoveries were higher in the HAS sample when compared with the results of actual flotation tests. As the mineralogy of the two ore samples was similar in terms of mineralogical and liberation characteristics, the only reason for the iii poor prediction of the model for the HAS sample was due to the change in the flotation pulp conditions for the HAS sample. There were two possible reasons for this change in the flotation response of the HAS sample. One was the higher levels of pyrite present in the HAS sample com...

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Entrainment of Particles into Flotation Froths

Cited by 133 publications

References 8 publications

Separation of cellulose fibres from pulp suspension by froth flotation fractionation

Separation of cellulose fibres from pulp suspension by froth flotation fractionation

Mitigating the deleterious effect of clay minerals on copper flotation

Selective flotation of enargite from copper sulphides in complex ore systems

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