Recent experimental advances for understanding bubble-particle attachment in flotation

Xing, Yaowen; Gui, Xiahui; Pan, Liyang; Pinchasik, Bat El; Cao, Yijun; Liu, Jiongtian; Kappl, Michael; Butt, Hans‐Jürgen

doi:10.1016/j.cis.2017.05.019

Cited by 221 publications

(82 citation statements)

References 284 publications

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“…The specific preparation methods of the hydrophobic surfaces and the measurement techniques seem to have an important influence on the results. Several mechanisms for hydrophobic attraction have been proposed, including entropic effects due to molecular re-arrangement of water near hydrophobic surfaces, electrostatic effects, correlated charge fluctuations or correlated dipole interactions, bridging by nanobubbles, and separation-induced cavitation due to the metastability of the intervening film [6]. Summarizing the existing literature, the experimental data relating to the hydrophobic force can usually be described quantitatively using two formulae, namely an exponential decay law (single exponential and double exponential) and a power decay law [7].…”

Section: Theoretical Modelmentioning

confidence: 99%

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Role of Collectors and Depressants in Mineral Flotation: A Theoretical Analysis Based on Extended DLVO Theory

et al. 2017

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A theoretical analysis was conducted to study the role of collectors and depressants in flotation, based on the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, where the hydrophobic force is considered. The collector-coated hydrophilic particle and the depressant-coated hydrophobic particle are simplified to a sphere uniformly covered with respectively hydrophobic and hydrophilic nanometer-sized hemispherical asperities of identical radius. Results show that the role of a collector in bubble-particle attachment is to create an attractive hydrophobic force and thus overcome the repulsive van der Waals and electrostatic forces. Moreover, increasing the length of the hydrophobic part of the collector molecule is a more effective way to enhance flotation recovery, compared to increasing the collector concentration. For a depressant, however, its function mechanism is to create a strong electrostatic double-layer force, while the suppression of the hydrophobic force plays a secondary role in decreasing the bubble-particle attachment barrier. The depressant molecule length is also a dominant parameter in designing a powerful depressant.

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Section: Theoretical Modelmentioning

confidence: 99%

“…The rising air bubbles carry hydrophobic particles to form a froth layer, which is then conveyed to the launders, while the hydrophilic particles sink to the bottom of the cell to the reject [4,5]. Among all the factors that influence the flotation performance, bubble-particle attachment is the key for successful flotation [6,7].…”

Section: Introductionmentioning

confidence: 99%

Role of Collectors and Depressants in Mineral Flotation: A Theoretical Analysis Based on Extended DLVO Theory

et al. 2017

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“…Foam is thermodynamically unstable and dissipates through self-destructive processes due to liquid drainage, Ostwald ripening, and bubble coalescence (Carey and Stubenrauch, 2010;Wang et al, 2017). The issues of foamability and foam stability are very important for numerous industrial applications such as mineral flotation (Drzymala and Kowalczuk, 2018;Kowalczuk and Drzymala, 2017;Xing et al, 2017;Zheng et al, 2017), wastewater treatment (Bournival et al, 2014;Fruhner et al, 2000), tertiary oil recovery (Ramaswamy et al, 2007), personal care products, etc. Particularly, foam stability is known to play a significant role in determining the mineral grade and recovery efficiency in mineral-flotation operations.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Properties of Aqueous Foams Stabilized by Cetyltrimethylammonium Bromide in Terms of Free Drainage and Bubble Size

Wang

Cao

et al. 2019

J Surfact & Detergents

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Although foams stabilized by surfactants have been the subject of massive investigations and great achievements were made over the past few years, many questions concerning their properties are still not well understood. The aim of this study is to examine the effect of the cetyltrimethylammonium bromide (CTAB) concentration on the foam properties and illustrate the interaction between liquid drainage and bubble size evolution. Experiments were carried out at varying CTAB concentrations ranging from 0.1 to 5.0 times the critical micelle concentration (CMC), where the variation of the liquid content of foam and bubble size was simultaneously determined using a commercially available FoamScan device. The results showed that the foam properties (both foamability and foam stability) of CTAB were largely dependent on the surfactant concentration when concentrations c < CMC but this effect did not scale linearly with concentration. When c ≥ CMC, both foamablity and foam stability were nearly concentration independent, while the latter showed a small decrease due to the formation of micelles. In addition, the correlation between free drainage and bubble size evolution indicated that the increase of bubble size could indeed enhance the foam drainage.

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“…In recent years, progress has been made on the studies of bubble-particle attachment using AFM [15][16][17][18][19]. However, the direct force measurement between an air bubble and a solid particle is always accompanied by the deformation of the gas-liquid interface by both the hydrodynamic and surface forces [20]. This poses a challenge in determining the absolute separation and the surface force between the bubbles and the particles in water.…”

Section: Introductionmentioning

confidence: 99%

Effect of Dodecane and Oleic Acid on the Attachment between Oxidized Coal and Bubbles

Xing

Cao

et al. 2018

Minerals

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Abstract:The objective of this study is to explain the different flotation responses observed in oxidized coal flotation when using a nonpolar flotation collector, dodecane, versus a polar flotation collector, oleic acid. Particularly, the effect of each flotation collector on bubble-coal particle attachment was investigated. Colloidal probe atomic force microscopy (AFM) was used to directly measure the force between a model coal surface and a model bubble in the presence of either dodecane or oleic acid. Pyrolytic graphite (PG) treated with oxygen plasma and a polymethylmethacrylate (PMMA) particle were selected to represent the model oxidized coal surface and model bubble. High speed visualization for bubble-oxidized coal attachment was used to monitor the attachment behavior between bubble and oxidized coal in presence of dodecane and oleic acid, respectively. It was found that the force between the oxidized PG and the PMMA particle in Milli-Q water was monotonically repulsive, illustrating that oxidized coal particles attach onto bubble surface with difficulty. The flotation recovery using a traditional hydrocarbon oil, dodecane, was always lower than when oleic acid was used at a low dosage (300-1100 g/t). The force measurements showed that an attractive hydrophobic force was introduced when a 0.01 mM oleic acid solution was used, while the force was still repulsive in presence of a 0.01 mM dodecane solution. The minimum contact time for successful attachment between oxidized coal surface and bubbles in the presence of 0.01 mM oleic acid is much shorter than that in 0.01 mM dodecane. However, a high flotation recovery of 85.81% was obtained when dodecane concentration was further increased to 1700 g/t. The significant jump into contact effect observed in the AFM force curves and the short induction time in the presence of 1 mM dodecane solution was responsible for this high flotation recovery.

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Recent experimental advances for understanding bubble-particle attachment in flotation

Cited by 221 publications

References 284 publications

Role of Collectors and Depressants in Mineral Flotation: A Theoretical Analysis Based on Extended DLVO Theory

Role of Collectors and Depressants in Mineral Flotation: A Theoretical Analysis Based on Extended DLVO Theory

Investigation on the Properties of Aqueous Foams Stabilized by Cetyltrimethylammonium Bromide in Terms of Free Drainage and Bubble Size

Effect of Dodecane and Oleic Acid on the Attachment between Oxidized Coal and Bubbles

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