Frother Effects on Bubble Motion in A Swarm

Zhou, Zunning; Egiebor, Nosa O.; Plitt, L. R.

doi:10.1179/cmq.1993.32.2.89

Cited by 15 publications

(1 citation statement)

References 18 publications

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“…The frother changes the bubble velocity as bubbles with a frother rise more slowly than those without a frother [15][16][17]. This decreased bubble rise speed in the presence of a frother is attributed to a change in drag force, caused by interaction between the frother and water molecules, bubble size, and bubble shape (more spherical bubbles are formed with a frother) [15,[18][19][20]. The rise speed of bubbles influences the probability of collision in flotation, ultimately influencing flotation performance [15].…”

Section: Introductionmentioning

confidence: 99%

Flotation of Carbonaceous Matter from a Double Refractory Gold Ore: The Effect of MIBC on Flotation Performance and Kinetics

2021

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The use of alkaline pressure oxidation to pretreat refractory gold ore often results in insufficient gold recovery (<60%) in downstream thiosulfate leaching. To improve gold recovery, flotation was considered for the separation of carbonaceous matter (C-matter). In this study, the effect of MIBC on C-matter flotation was investigated to understand the role of the frother in bubble and froth formation and on flotation kinetics. MIBC dosages between 30 and 150 g/t were used in combination with 500 g/t of kerosene as a collector. The results showed that the recovery and selectivity of C-matter were improved with increasing MIBC dosages. Improved selectivity at higher MIBC dosages was attributed to faster C-matter recovery as bubble size decreased to the critical coalescence concentration (CCC) and to changes to the foam structure. Analysis of flotation kinetics showed that the flotation rate increased as the MIBC dosage increased due to the decreasing bubble size and the reduced induction time caused by the interaction between the collector and the frother. The results of this study explain the role of MIBC in C-matter flotation and can be used as a design basis for scavenger-cleaner flotation testing. Overall, the results show the potential for flotation as a means to improve gold recovery in thiosulfate leaching through the removal of C-matter.

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Section: Introductionmentioning

confidence: 99%

Flotation of Carbonaceous Matter from a Double Refractory Gold Ore: The Effect of MIBC on Flotation Performance and Kinetics

2021

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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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Effect of natural surfactants released from athabasca oil sands on air holdup in a water column

Zhou¹,

Xu²,

Masliyah³

2000

Can J Chem Eng

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. are among the pioneers in commercial exploration of Canadian Athabasca oil sands using the Clark Hot Water Extraction (CHWE) process (Bowman, 1969; Hepler and Smith, 1994). In this process, mined oil sands are digested in hot water under mechanical agitation in a tumbler. Small quantities of caustic are added to the slurry to facilitate bitumen detachment (liberation) from sand surfaces. Since bitumen and water have similar densities, effective recovery of the liberated bitumen from slurry is accomplished by flotation using air bubbles as carriers. In an aerated slurry, bitumen droplets attach to and engulf air bubbles, which float to the top of the slurry to form a bitumen-rich froth in a primary separation vessel (PSV). Bitumen droplets remaining in the slurry are further recovered using conventional mechanical flotation cells. It is clear that the performance of bitumen flotation dictates the overall bitumen recovery.The aforementioned commercial bitumen extraction process is found to be adequate for processing estuarine ores, which contain more than 10% bitumen by weight and a small amount of fine clays. This type of ores is often referred to as "good ores". In this case, a bitumen recovery of greater than 90% can be achieved even with little or no caustic addition (Schramm and Smith, 1987; Hepler and Smith, 1994). In contrast, the existing technology becomes inefficient when processing marine ores, which contain less than 8% bitumen and a relatively large amount of fine clays. A much higher caustic dosage greater than 0.05?40 by weight of the oil sands processed is often added for processing marine ores. But the maximum bitumen recovery achievable remains much lower than 90% (Sanford, 1983; Schramm et al., 1985; Bichard, 1987; Schramm and Smith, 1987). The marine ores are therefore referred to as "poor ores" to characterize their poor processibility.Extensive research work has been conducted in an attempt to understand the causes of poor processibility of marine ores in comparison with estuarine ores. Most of the previous investigations focused on the electrokinetic and interfacial tension analysis (Isaacs and Smolek, 1983; Chow, 1983, 1985; Hsi, 1989, Hepler and Smith, 1994). These early studies provided adequate guidelines for some systems. However, the results were rather case-specific and could not account for complex phenomena in the flotation vessels (Hepler and Smith, 1994). To have a better control of bitumen flotation, it is necessary to consider as many process variables as possible in a comprehensive and systematic manner.Bitumen flotation occurs in a complex system, involving interactions among solids, water, bitumen and air bubbles in the presence of different surface active and ionic species. These species were either added inten-

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Frother Effects on Bubble Motion in A Swarm

Cited by 15 publications

References 18 publications

Flotation of Carbonaceous Matter from a Double Refractory Gold Ore: The Effect of MIBC on Flotation Performance and Kinetics

Flotation of Carbonaceous Matter from a Double Refractory Gold Ore: The Effect of MIBC on Flotation Performance and Kinetics

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

Effect of natural surfactants released from athabasca oil sands on air holdup in a water column

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