Generation and characterization of submicron size bubbles

Wu, Chendi; Nesset, Kirsten; Masliyah, Jacob H.; Xu, Zhenghe

doi:10.1016/j.cis.2012.06.012

Cited by 101 publications

(71 citation statements)

References 70 publications

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“…In this section, the effect of collector and/or frother addition on bubble-particle attachment is studied. shown in our previous study, [38] SDS readily adsorbs at the bubble-water interface, reducing the bubble zeta potential, i.e., becoming more negative. For example at pH 6 (Fig.…”

Section: Surfactant and Frother Solutionsmentioning

confidence: 50%

“…The sub-micron size gas bubbles generated using this method have a bubble size of d 50 ~ 350 nm which remain stable for up to 24 hr with the presence of surfactant. [38] A Rushton impeller 5.7 cm in diameter and 1.2 cm in blade width was used throughout the study. Entrainment of ambient gas was minimized by operating the cell at maximum volume …”

Section: Methodsmentioning

confidence: 99%

“…The observed configuration of gas bubble attaching to alumina particle is not unexpected when considering that the alumina particles (d 50 ~ 868 nm) are of diameters twice greater than the diameter of the gas bubbles ( ~ 350 nm). [38] Furthermore, the alumina particles are not fully covered by the gas bubbles due to insufficient number of bubbles present in the system of almost equal number of gas bubbles and solid particles as controlled on purpose for the experiments.…”

Section: Individual Componentsmentioning

confidence: 99%

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Studying bubble–particle interactions by zeta potential distribution analysis

Wang

Harbottle

et al. 2015

Journal of Colloid and Interface Science

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Over the last decade, Xu and Masliyah have pioneered an approach to characterize the interactions between particles in dynamic environments of multicomponent systems by measuring zeta potential distributions of individual components and their mixtures. Using a Zetaphoremeter, the measured zeta potential distributions of individual components and their mixtures were used to determine the conditions of preferential attachment in multicomponent particle suspensions. The technique has been applied to study the attachment of nano-sized silica and alumina particles to sub-micron size bubbles in solutions with and without the addition of surface active agents (SDS, DAH and DF250). The degree of attachment between gas bubbles and particles is shown to be a function of the interaction energy governed by the dispersion, electrostatic double layer and hydrophobic forces. Under certain chemical conditions, the attachment of nano-particles to sub-micron size bubbles is shown to be enhanced by in-situ gas nucleation induced by hydrodynamic cavitation for the weakly interacting systems, where mixing of the two individual components results in negligible attachment. Preferential interaction in complex tertiary particle systems demonstrated strong attachment between micron-sized alumina and gas bubbles, with little attachment between micron-sized alumina and silica, possibly due to instability of the aggregates in the shear flow environment.

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Section: Surfactant and Frother Solutionsmentioning

confidence: 50%

Section: Methodsmentioning

confidence: 99%

Section: Individual Componentsmentioning

confidence: 99%

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Studying bubble–particle interactions by zeta potential distribution analysis

Wang

Harbottle

et al. 2015

Journal of Colloid and Interface Science

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“…Furthermore, with the increase of NaOl concentration, the average bubble size decreases and the average count rate increases. Research has shown that the number of tiny bubbles in solution are positively correlated with the value of count rate [29]. It indicates that more and smaller NBs are produced as the concentration of NaOl increases.…”

Section: Nbs Properties and Their Influence On Flotation Bubble Sizementioning

confidence: 87%

“…It indicates that more and smaller NBs are produced as the concentration of NaOl increases. With the increasing of NaOl concentration, the surface tension of solution decreases, benefiting the maintenance of newly generated bubbles by preventing bubbles bursting and coalescence as well [29]. In addition, according to the nuclei theory, there are many gas nuclei stored in the cavities of the particles [30].…”

Section: Nbs Properties and Their Influence On Flotation Bubble Sizementioning

confidence: 99%

Different Flotation Performance of Ultrafine Scheelite under Two Hydrodynamic Cavitation Modes

Zhou

Shi

et al. 2018

Minerals

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Abstract:In industrial practice, hydrodynamic cavitation (HC) is commonly triggered by jetting either reagent solution or pulp. Although both methods can enhance mineral flotation, are their roles the same? There are few research studies in the field, which severely limits our understanding on mineral flotation combined with HC. Therefore, in this study, the flotation of ultrafine scheelite with HC pretreatments of reagent solution and pulp (abbreviated to be HCPS and HCPP, respectively) was studied and compared through flotation tests, zeta potential analysis, microscope tests, and shear yield stress measurements. The results of flotation tests show that both HCPS and HCPP can enhance the final flotation performance, but in general, HCPP leads to greater improvements on the final flotation recovery. The presence of (hydrophobized) scheelite particles brings extra gas nuclei for the cavitation-flotation system, suggesting that more NBs may be produced in the case of HCPP compared with HCPS. These tiny bubbles remarkably reduce the size distribution of bubbles in the flotation system, thus increasing the particle-bubbles collision probability. Increase in particle aggregation may be another reason why flotation with HCPP results in a higher flotation recovery. The adherence of NBs on hydrophobized particles decreases the (absolute) surface charge of the solids, resulting in a smaller repulsive force among particles and more significant particle aggregation, which is confirmed by the microscope tests and shear yield stress measurements.

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Role of mineral flotation technology in improving bitumen extraction from mined Athabasca oil sands—II. Flotation hydrodynamics of water‐based oil sand extraction

Zhou¹,

HaiHong²,

Chow³

et al. 2019

Can J Chem Eng

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Bitumen flotation hydrodynamics in water‐based oil sand extraction is critically reviewed by comparing aeration of oil sand slurries with mineral flotation. The role of the two‐stage particle‐bubble attachment model in flotation is emphasized as a means to accelerate bitumen flotation recovery. It involves the generation of micro/nanobubbles and their frosting on hydrophobic bitumen droplets, followed by their attachment to a flotation‐size bubble via its coalescence with the nanobubbles frosted on the bitumen. Nanobubble generation by hydrodynamic cavitation demonstrates that the size of nanobubbles can be reduced, and the number of nanobubbles increased by fast liquid flow, intensified agitation, high dissolved gas content and surfactant concentration. The mechanism of pre‐existing gas nuclei in enhancing nanobubble generation by cavitation is utilized to produce a large volume of stabilized nanobubbles for practical flotation, by continuously recirculating the stream through a gas saturation tank or a cavitation tube. The aeration of oil sand slurries in hydrotransport pipelines is analyzed based on its similarity to dissolved air flotation. Bitumen extraction recovery increased significantly with the presence of nanobubbles in the system. The role of improved flotation hydrodynamics in bitumen recovery is briefly discussed in terms of the Suncor operation using flotation columns to process oil sand middling streams. Future research should be directed at understanding bitumen flotation kinetics, optimizing size ranges of nanobubbles for maximized flotation recovery, minimizing wearing of cavitation tubes in industrial operations, and intensifying the role of in‐situ nanobubble nucleation on hydrophobic particles/bitumen droplets in flotation, especially for bitumen extraction from underperforming oil sands.

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Generation and characterization of submicron size bubbles

Cited by 101 publications

References 70 publications

Studying bubble–particle interactions by zeta potential distribution analysis

Studying bubble–particle interactions by zeta potential distribution analysis

Different Flotation Performance of Ultrafine Scheelite under Two Hydrodynamic Cavitation Modes

Role of mineral flotation technology in improving bitumen extraction from mined Athabasca oil sands—II. Flotation hydrodynamics of water‐based oil sand extraction

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