Wall function model for particulate fouling applying XDLVO theory

Ojaniemi, Ulla; Riihimäki, Markus; Manninen, Mikko; Pättikangas, Timo

doi:10.1016/j.ces.2012.08.004

Cited by 28 publications

(9 citation statements)

References 30 publications

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“…The classical DLVO theory only considering the electrostatic and van der Waals interaction fails when the surfaces are very hydrophilic or very hydrophobic, for which the contact angle of water is less than 15° (hydration forces) or greater than 64° (hydrophobic forces) (Derjaguin and Churaev, 1989). But the hydrophobic aggregation of particles can be well explained in the extended DLVO theory concerning polar interfacial interaction (Hoek and Agarwal, 2006;Hu and Dai, 2003;Ninham, 1999;Ojaniemi et al, 2012;Yoon and Mao, 1996).…”

Section: Calculation Of the Interaction Energymentioning

confidence: 99%

Depressing effect of fine hydrophilic particles on magnesite reverse flotation

Yao

Yin

Gong

2016

International Journal of Mineral Processing

120

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The influence of fine particles on the flotation separation of minerals is becoming increasingly important as new, fine grained deposits are exploited. Fine particles float poorly and less selectively under normal flotation conditions, having detrimental effects on recovery of other minerals. The reasons of this interacting effect are complex, which may be entrainment, pH variation, dissolved ions from mineral surfaces, aggregation/dispersion and coating behavior of particles or even the competitive adsorption effect. In this study, the influence of fine magnesite and dolomite on the flotation of quartz was investigated. It was found that at pH=9.2~9.5 and with DDA dosage of 8.6×10 −4 , the recovery of coarse (-100+65µm) quartz was reduced dramatically from 96.66% to 37.15% when the content of quartz was 5% in the flotation with fine (-5µm) magnesite, and when the content of fine dolomite was increased from 2.5% to 20%, the recovery of coarse quartz was reduced from 91.20% to 75.08%. To examine the reasons, zeta potential, zero point of charge and contact angles of magnesite, dolomite and quartz were measured in the absence and presence of dodecylamine (DDA). The interaction energies between particles were then calculated. Results showed that the aggregation behavior of mineral particles was likely to be the reason. Interaction energy calculated based on Extended-DLVO (Derjaguin-Landau-Verwey-Overbeek) theory predicted that in DDA surfactant solution, the interaction forces between magnesite and quartz, dolomite and quartz were attractive, between dolomite and magnesite was repulsive. The experimental results are in excellent agreement with the theoretically predicted results. The aggregation caused by interacting behavior explains the depressing effect of fine hydrophilic particles on magnesite reverse flotation.

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Section: Calculation Of the Interaction Energymentioning

confidence: 99%

Depressing effect of fine hydrophilic particles on magnesite reverse flotation

Yao

Yin

Gong

2016

International Journal of Mineral Processing

120

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“…1 For instance, they are key elements in environmental pollution and particulate contamination control, fouling of heat exchangers, 2,3 oil transport in pipelines, 4,5 sediment transport in rivers, 6 biofilm formation, 7 or liquid metal processing. 8 Depending on the system, the suspended particles may be solid particles or droplets.…”

Section: Introductionmentioning

confidence: 99%

Analysis of non‐Brownian particle deposition from turbulent liquid‐flow

et al. 2015

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International audienceThe deposition of non-Brownian particles from turbulent liquid-flow onto channel walls is numerically analyzed. Theapproach combines Lagrangian particle tracking with a kinematic model of the near-wall shear layer. For nonbuoyantparticles, direct interception is the main deposition mechanism and the deposition velocity scales as the particle diameter(in wall units) to the power of 1.7. When wall/particle hydrodynamic interactions are taken into account, the depositionvelocity is significantly reduced and the correction factor scales as the cubic root of the wall roughness to particlediameter ratio. For buoyant particles, sedimentation is usually the predominant deposition mechanism and the hydrodynamicinteractions significantly affect the deposition velocity when the drainage characteristic time driven by buoyancyis of the order of the particle residence time close to the wall. Last, a wall-function for the suspended particles is proposed

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“…While hydrodynamic forces forward the flocs close to the membrane surface, it is the thermodynamic forces (thermodynamic interactions) that cause binding (adhesion) of the flocs to the membrane. The particle-substrate thermodynamic interactions in aqueous media can be profiled via the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory [26,27]. Different size flocs may possess different thermodynamic interactions, and then show different adhesion behaviors.…”

mentioning

confidence: 99%