Micro- and nano-scale phenomena effect on bubble size in mechanical flotation cell

Jávor, Zoltán; Schreithofer, Nóra; Heiskanen, Kari

doi:10.1016/j.mineng.2014.09.010

Cited by 13 publications

(8 citation statements)

References 25 publications

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“…According to the well-known Young’s equation, a reduced surface tension at the water–air interface in the presence of frothers leads to the weakening of hydrophobic interactions between an air bubble and a solid particle . From this fundamental principle, a reduction of the recovery of quartz with increasing frother concentration would be expected but is certainly not observed even when the critical coalescence concentration(CCC) , of DF250 (7.2 ppm) is surpassed, i.e., when the Sauter diameter of the bubbles does not decrease with further addition of the frother. Indeed, the contrary is shown in Figure , where the well-documented positive effects on the use of frothers are corroborated.…”

Section: Resultsmentioning

confidence: 99%

On the Colloidal Behavior of Cellulose Nanocrystals as a Hydrophobization Reagent for Mineral Particles

2021

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In the search for more sustainable alternatives to the chemical reagents currently used in froth flotation, the present work offers further insights into the behavior of functionalized cellulose nanocrystals as mineral hydrophobization agents. The study corroborates that hexylamine cellulose nanocrystals (HACs) are an efficient collector for the flotation of quartz and also identifies some particular characteristics as a result of their colloidal nature, as opposed to the water-soluble reagents conventionally used. To investigate the individual and collective effects of the frother and HACs on the attachment of particles and air bubbles, an automated contact timer apparatus was used. This induction timer measures particle-bubble attachment probabilities ( P att ) without the influence of macroscopic factors present in typical flotation experiments. This allowed the study of the combined influence of nanocellulose and frother concentration on P att for the first time. While HACs readily adsorb on quartz modifying its wettability, the presence of a frother leads to a drastic reduction in P att up to 70%. The improved recovery of quartz in flotation cells might thus be attributed to froth stabilization by HACs, perhaps acting as a Pickering foam stabilizer. Among the main findings, a tendency of HACs to form mineral agglomerates was identified and further explained using the extended DLVO theory in combination with measured adsorption rates in a quartz crystal microbalance. Therefore, this study distinguishes for the first time the antagonistic effect of frothers on P att and their synergies with HACs on the stabilization of orthokinetic froths through the hydrophobization mechanism unlike those of typical water-soluble collectors.

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Section: Resultsmentioning

confidence: 99%

On the Colloidal Behavior of Cellulose Nanocrystals as a Hydrophobization Reagent for Mineral Particles

2021

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“…The observations by Javor et al, (2015) also conclude that highly surface-active agents decrease bubble size at its lower concentration than the weak agents because in the presence of weakly surfaceactive reagents, the molecule exchange occurs rapidly at the air/liquid interface due to the quick diffusion controlled adsorption/desorption. However, the adsorption/desorption of highly surfaceactive molecules occurs with a long characteristic time caused by the molecule reorientation which sharply diminishes the bubble size.…”

Section: Effect Of Nanoscale Bubble and Particle On Bubble Size Distrmentioning

confidence: 89%

Dynamics of bubble-particle interaction in different flotation processes and applications - a review of recent studies

Patnaik¹,

Menon²,

Gupta³

et al. 2020

Physicochem. Probl. Miner. Process.

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Flotation process involves aggregation of the particles based on the material/compound type of random mixtures such as ores and seawater. It is primarily used in pretreatment of water desalination and other industrial applications. The process makes use of various fluid mechanics principles as multifluids are involved. The multi-fluids in most of the flotation processes are of different phases, such as air and water. Like any other process, the efficiency of flotation is important, and hence most of the studies have been dedicated to understanding how the various parameters are affecting the flotation process. Among various parameters, fluids properties and flow parameters chiefly affect the flotation process. In particular, the bubble-particle interaction of the flotation process has been of interest as it is one of the cost-effective ways to enhance flotation efficiency. In this review, the authors present the latest developments in such parametric studies. This paper could be of interest to research students, academic researchers, and practitioners who want to contribute to (or take from) flotation research.

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“…The routine consists on finding an adaptive threshold level, defining the edges of the bubbles and fitting to an ellipse on these edges, finally calculating the equivalent diameter based on the maximum and minimum diameter of the ellipse using Eq. 3 (Jávor et al, 2015):…”

Section: Bubble Size Foam Depth and Foam Stabilitymentioning

confidence: 99%

“…It should be noted that the minimum bubble diameter detected with this method was of 0.02 mm. The Sauter mean diameter (D32) of each measured concentration was calculated based on the diameter results received from the MATLAB® routine (Jávor et al, 2015).…”

Section: Bubble Size Foam Depth and Foam Stabilitymentioning

confidence: 99%

Amphiphilic cellulose and surfactant mixtures as green frothers in mineral flotation. 2. Flotation of chalcopyrite and Cu-containing tailings

Nuorivaara

Serna-Guerrero

2020

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Micro- and nano-scale phenomena effect on bubble size in mechanical flotation cell

Cited by 13 publications

References 25 publications

On the Colloidal Behavior of Cellulose Nanocrystals as a Hydrophobization Reagent for Mineral Particles

On the Colloidal Behavior of Cellulose Nanocrystals as a Hydrophobization Reagent for Mineral Particles

Dynamics of bubble-particle interaction in different flotation processes and applications - a review of recent studies

Amphiphilic cellulose and surfactant mixtures as green frothers in mineral flotation. 2. Flotation of chalcopyrite and Cu-containing tailings

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