Modeling the bubble loading based on force balance on the particles attached to the bubble

Eskanlou, Amir; Chegeni, Mohsen Hemmati; Khalesi, Mohammad Reza; Abdollahy, Mahmoud; Huang, Qingqing

doi:10.1016/j.colsurfa.2019.123892

Cited by 22 publications

(7 citation statements)

References 44 publications

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“…4 is the flowability of materials inside the system. Liu (2015) and Eskanlou et al (2019) reported that as the particle size of a substance becomes finer, its ability to move and flow through the system decreases. In a relatively turbulent environment, interception and gravitational encountering govern the collision mechanism between pyrite and chalcopyrite particles (Hassanzadeh et al, 2018(Hassanzadeh et al, , 2019b.…”

Section: Impact Of Pyrite Grain Sizementioning

confidence: 99%

Effect of externally adding pyrite and electrical current on galvanic leaching of chalcopyrite concentrate

Asgari¹,

Hassanzadeh²,

Nazari³

et al. 2021

Physicochem. Probl. Miner. Process.

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Although the operating properties of Galvanox TM leaching have been widely studied in the literature, several factors concerning chalcopyrite passivation during the process remain unknown so far. The present work hence aims at investigating the significant effect of externally added pyrite features with a particular focus on its particle size (d80 of 0.52, 20, 45 and 2000 µm) through a series of experiments performed in a 2-L stirred-tank electro-reactor. To this end, the role of pyrite: chalcopyrite ratio (0.49:1, 2:1 and 4:1) and presence of electrical current were examined while the rest of the parameters kept constant (80 °C temperature, 400-500 mV (Ag/AgCl) redox potential, pulp density of 10% (w/v), and stirring rate of 1200 rpm). Plus, kinetic models of the leaching tests were studied based on the diffusion and chemical controlling concepts. It was found that the coarser the pyrite particles, the more favorable the copper extraction from the concentrate due to acceleration of reactions in the cathodic electrode and high mass transfers. However, this was in contradiction with the existing reports in the literature. Moreover, galvanic interactions became intensive in the presence of pyrite meaning extensive chalcopyrite dissolution with significantly reduced passivation. Ultimate copper extraction values of 24.17±1.25%, 55.79±0.91% and 57.26±1.59% were resulted at Py:Cp ratios of 0.49:1 (natural), 2:1 and 4:1, respectively. The results showed that maximum copper recovery of 67.32±2.34% was obtained at an optimum condition of pyrite grain size=2000 µm, Py:Cp=4:1, current application=500 mA, 8 h and 80 °C. Finally, detailed kinetic modeling indicated that the chemical control mechanism was dominant in the early reaction stages (t<3.5 h) concerning the availability of fresh surface for chemical agents; however, the second half of the process (8.0 h>t>3.5 h) was controlled by the diffusion control.

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Section: Impact Of Pyrite Grain Sizementioning

confidence: 99%

Effect of externally adding pyrite and electrical current on galvanic leaching of chalcopyrite concentrate

Asgari¹,

Hassanzadeh²,

Nazari³

et al. 2021

Physicochem. Probl. Miner. Process.

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“…In some cases, gravity can promote attachment when a particle penetrates an air bubble at a certain grazing trajectory collision angle (Schulze, 1989). Furthermore, detachment of some hydrophobic particles from the air-bubble bottom surface occurs due to the viscous drag force from the counter-current fluid motion (Eskanlou et al, 2019) or lower localized particle surface-to-volume ratio at higher particle surface roughness and sizes (Fornasiero and Filippov, 2017). Additionally, for particles with a density similar to carrying fluid, the gravity is insignificant relative to inertia.…”

Section: Introductionmentioning

confidence: 99%

How Air Entrapment in Hydrophobic Particle-water-air Mixtures Changes Post-wildfire Mudflow Composition

Tomac

2022

Preprint

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This paper shows critical new insights into how air entrapment affects the properties of rain-induced post-wildfire mudflows as a mixture of air bubbles, water, and hydrophobic sand. The idea of mudflows' internal structure containing trapped air bubbles is novel. Such mixtures can flow down slopes at incredible speeds, quickly blasting obstacles on the way and carrying large stone boulders and objects. The surficial soil particles turn hydrophobic due to the deposition of combusted organic matter during wildfires. Afterward, raindrops, splash, and erosion form devastating mudflows. We propose a new paradigm in which a significant amount of air remains entrapped in post-wildfire mudflow via hydrophobic particle-air attraction. Specific findings quantify the amount of air trapped within sandwater volumetric concentrations, the effect of intermixing energy, gravity, and sand particle size on outcome mudflow internal structure. As a result, little agglomerates of sand particles covering air bubbles characterize the mudflow mixture's internal structure.

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“…Besides, the method is less sensitive to the presence of slimes, therefore it is not needed to do the desliming process before flotation. Some studies reported that higher recovery and selectivity can be obtained via reverse anionic flotation (Araujo et al, 2005;Eskanlou et al, 2019;Filippov et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Application of magnetic separation and reverse anionic flotation to concentrate fine particles of iron ore with high sulfur content

Dehghani¹,

Khosravi²,

Pazoki³

et al. 2021

Physicochem. Probl. Miner. Process.

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The sulfur content in iron ore causes technical problems in the process of sintering iron ore in steel and alloys, and environmental problems in discharging the tailing. The major challenge in the iron ore processing plant is handling the finer particles. The key objectives of this research included the concentration of Band Narges Mine iron ore (< 150 µm) as well as the reduction of the sulfur content to achieve a marketable product. First, the mineralogical characterization of iron ore was established, which showed that Fe3O4, SiO2, and CaO were the predominant minerals in the ore body. Moreover, magnetite particles with a size of < 150 µm were mainly locked into the associated gangue mineral. Second, metallurgical experiments were conducted, including magnetic separation and froth flotation. To increase the iron grade and recovery and decrease the sulfur content, two separate process flowsheets were tested, three steps of magnetic separation with a magnetic field strength of 2000 G were used in the first process flowsheets, followed by regrinding to < 74 µm and application of a three-stage reverse flotation. The overall iron grade and recovery were 76.38% and 67.9%, respectively, from this flowsheet. A five-stage successive reverse flotation followed by three stages of magnetic separation at 1000 G was carried out in the second flowsheet. The final recovery and grade of iron for this flowsheet were 77.15% and 64.3%, respectively. The ultimate content of sulfur was estimated at 0.74%.

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Modeling the bubble loading based on force balance on the particles attached to the bubble

Cited by 22 publications

References 44 publications

Effect of externally adding pyrite and electrical current on galvanic leaching of chalcopyrite concentrate

Effect of externally adding pyrite and electrical current on galvanic leaching of chalcopyrite concentrate

How Air Entrapment in Hydrophobic Particle-water-air Mixtures Changes Post-wildfire Mudflow Composition

Application of magnetic separation and reverse anionic flotation to concentrate fine particles of iron ore with high sulfur content

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