Heterocoagulation behaviour of polymer latices with spherical silica

Furusawa, Kunio; Anzai, Chikai

doi:10.1016/0166-6622(92)80076-e

Cited by 87 publications

(59 citation statements)

References 9 publications

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“…Only S8 1 contains significant heteroaggregates. A higher dilution of S8 led to approximately the same results as S8 1 . All these samples led to a good fit with IACF for monodisperse spheres, and the measurements showed a very good dynamical contrast which make these results quantitatively more accurate.…”

Section: Resultsmentioning

confidence: 61%

“…Several studies have been carried out on systems containing oppositely charged particles [1][2][3][4]. It was shown [1] that the relative size of the particles determines the morphology of aggregation: if there is a significant difference in size, the small particles are adsorbed onto the large particles but if particles have comparable size, growth of large fractal clusters may take place. Heteroaggregation, which occurs together with or without homoaggregation was studied in [2] where the morphology of clusters was observed after performing electron microscopy on dried samples.…”

Section: Introductionmentioning

confidence: 99%

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Heteroaggregation, repeptization and stability in mixtures of oppositely charged colloids

Raşa

Philipse

Meeldijk

2004

Journal of Colloid and Interface Science

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We report a study of mixtures of initially oppositely charged particles with similar size. Dispersions of silica spheres (negatively charged) and alumina-coated silica spheres (positively charged) at low ionic strength, mixed at various volume ratios, exhibited a surprising stability up to compositions of 50% negative colloids as well as spontaneous repeptization of particles from the early-stage formed aggregates. The other mixtures were found to contain large heteroaggregates, which were imaged using cryogenic electron microscopy. Electrophoretic mobility, electrical conductivity, static and dynamic light scattering and sedimentation were studied as a function of volume fraction of the mixed dispersions to investigate particle interactions and elucidate the repeptization phenomenon.

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Section: Resultsmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Heteroaggregation, repeptization and stability in mixtures of oppositely charged colloids

Raşa

Philipse

Meeldijk

2004

Journal of Colloid and Interface Science

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“…If the system consists of particles significantly different in size and charge, adhesion of small particles on the larger ones may take place. This adhesion process can greatly affect the properties of the resulting dispersed system [2]. It is expected that particles with opposite charge will attract one another, leading to heteroaggregate formation, whereas particles with like charge should repel one another, keeping the system stable.…”

Section: Introductionmentioning

confidence: 99%

Stability of mixtures of charged silica, silica–alumina, and magnetite colloids

Viota

Raşa

Sacanna

et al. 2005

Journal of Colloid and Interface Science

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We report experiments on the stability of aqueous mixtures of charged colloidal magnetite and charged silica and silica covered with alumina particles of similar size. First, positively charged magnetite dispersions were mixed with negatively charged silica dispersions at pH 4, at different volume ratios and low colloid volume fractions, producing mixtures which were stable over a period of weeks despite the expected electrostatic attraction between the oppositely charged particles. When magnetite particles were mixed with positively charged silica covered with alumina at pH 4 under exactly the same conditions, some of the systems separated to form a magnetite sediment. When the volume fraction of the initial dispersions was increased, the behavior of the mixtures was the opposite: positive magnetite/negative silica mixtures were unstable at intermediate volume ratios. The unexpected behavior of the mixtures was investigated by means of electrophoretic mobility, initial susceptibility, and dynamic light scattering measurements as well as sedimentation experiments.  2005 Elsevier Inc. All rights reserved.

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“…Heterocoagulation of fine particles is important for many industrial applications, such as separation/deposition/removal of fine particles [37][38][39][40][41][42][43][44][45][46]. The separation of a mixture of fine and ultrafine particles can be performed by mineral processing methods, i.e., flotation [37,38], emulsion flotation [39][40][41], and two-liquid flotation [20,42].…”

Section: Heterocoagulation Of Particle and Non-polar Oil Dropletmentioning

confidence: 99%

Two-Liquid Flotation for Separating Mixtures of Ultra-Fine Rare Earth Fluorescent Powders for Material Recycling—A Review

Otsuki

Dodbiba

Fujita

2018

Colloids and Interfaces

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This paper reviews two separation methods applying two-step two-liquid flotation for recovering ultra-fine rare earth fluorescent powders (i.e., red, green, and blue). The paper aims to extract the science behind separation by two-liquid flotation, and to provide resulting engineering tips for material recycling. Two-liquid flotation, also called liquid-liquid extraction, involves two solvents (i.e., non-polar and polar solvents) to capture hydrophobic/hydrophobized particles at their interface, and a surfactant to selectively modify the surface property of the target powder(s). For separating a three powder mixture, two different developed flowsheets, composed of two-step separation are discussed. The major difference found was the polar solvents used. The first flowsheet (called the aqueous-organic system) employed water as a polar solvent while the second flowsheet (called the organic-organic system) utilized N,N-dimethylformamide, DMF as a polar solvent. The organic-organic system at the optimized conditions achieved both the grade and recovery of all the separated fluorescent powders at greater than 90% while the aqueous-organic system did not satisfy these criteria. This paper also reviews the mechanism behind the separation, as well as performing a cost comparison between the two methods. The cost comparison indicates that the organic-organic system is a more cost effective method for recovering rare earth fluorescent powders than the aqueous-organic system. Since the size of powders (i.e., several µm) is too small for the application of conventional separation technologies (e.g., froth flotation), two-liquid flotation is a unique pathway for the material recycling of ultra-fine rare earth fluorescent powders.

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Heterocoagulation behaviour of polymer latices with spherical silica

Cited by 87 publications

References 9 publications

Heteroaggregation, repeptization and stability in mixtures of oppositely charged colloids

Heteroaggregation, repeptization and stability in mixtures of oppositely charged colloids

Stability of mixtures of charged silica, silica–alumina, and magnetite colloids

Two-Liquid Flotation for Separating Mixtures of Ultra-Fine Rare Earth Fluorescent Powders for Material Recycling—A Review

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