Flocculation and reflocculation of clay suspension by different polymer systems under turbulent conditions

Yoon, Se-Young; Deng, Yulin

doi:10.1016/j.jcis.2004.05.011

Cited by 116 publications

(48 citation statements)

References 10 publications

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“…As a result, cationic PAM showed better reflocculation ability. Yoon and Deng (2004) considered that the initial flocculation ability of the polymer is closely related to the molecular weight, but the reflocculation ability is more dominated by the charge density of the polymer.…”

Section: The Effect Of Charge Type and Molecular Weight Of Pam On Thementioning

confidence: 99%

Characterization of kaolin flocs formed by polyacrylamide as flocculation aids

Zhu

et al. 2009

International Journal of Mineral Processing

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a b s t r a c t a r t i c l e i n f oAlthough the synthetic organic polymers have been widely applied as flocculant aids to improve solid-liquid separation efficiency, it is not very clear how the charge type and molecular weight of the polymers influence the characteristics of flocs. In this paper, floc characteristics, such as floc size, density, structure, strength and reversibility were investigated in details in terms of their response to the polyacrylamide (PAM) with different charge types and molecular weights. Laser light scattering, image analysis and settling technology were employed simultaneously. The results showed that floc size induced by anionic PAM with medium molecular weight (A130) and ultra high molecular weight (A115) was 419 µm and 438 µm respectively, correspondingly, floc size induced by cationic PAM with medium molecular weight (C448) and very high molecular weight (C498) was 731 µm and 796 µm. Meanwhile, floc fractal dimension was inversely proportional to polymer molecular weight and the values were between 1.91 and 2.40. In addition, floc density was affected by molecular weight of anionic PAM more dramatically than that of cationic PAM. For a given floc size, the density increased with molecular weight. Furthermore, flocs formed by cationic PAM showed much greater shear-resistant ability and reversibility than anionic PAM. Nevertheless, the poor reversibility of the flocs formed by high molecular weight was also observed. An explanation for the resultant floc characteristics was offered in terms of flocculation mechanisms.

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Section: The Effect Of Charge Type and Molecular Weight Of Pam On Thementioning

confidence: 99%

Characterization of kaolin flocs formed by polyacrylamide as flocculation aids

Zhu

et al. 2009

International Journal of Mineral Processing

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“…The deflocculation and reflocculation experiments for the one-component systems were conducted by altering the stirring speed repeatedly between 300 rpm and 900 rpm every 100 s, for a total of 750 s (Yoon and Deng 2004). The deflocculation and reflocculation experiments for the two-component systems were performed by altering the stirring speed repeatedly between 900 rpm and 300 rpm.…”

Section: Photometric Dispersion Analyzer Experimentsmentioning

confidence: 99%

“…Furthermore, an excessive level of flocculation is not desired, as it leads to non-uniform paper formation. The degree of flocculation and reflocculation, which affects the floc characteristics, plays an important role on the retention and dewatering process, depending on the type of predominant flocculation mechanism (Norell et al 1999;Yoon and Deng 2004). In the course of papermaking, particles may flocculate, deflocculate, or reflocculate simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Utilizing Cellulose Nanofibril as an Eco-Friendly Flocculant for Filler Flocculation in Papermaking

He¹,

Cho²,

Lee³

et al. 2016

BioResources

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Cellulose nanofibril (CNF) is a type of nano-sized cellulosic material with a high aspect ratio and a large specific surface area, which makes it a promising additive to flocculate particles such as fillers. In this study, CNFs were prepared by wet disk-milling with three different degrees of fibrillation. The effect of the CNF on the flocculation of precipitated calcium carbonate (PCC) was elucidated. A photometric dispersion analyzer (PDA) investigated the flocculation phenomena resulting from the interactions between the PCC and the CNF, or polymers, in real-time. The results clearly showed that CNF could be used to control the flocculation behavior of the PCC particles. Scanning electron microscopy (SEM) images showed that the CNFs functioned as bridges between the two PCC particles. A significant reflocculation capability was observed in one-and two-component systems that consisted of CNFs. The addition of cationic starch (C-starch) could induce more efficient flocculation within a twocomponent system.

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“…In fact, in many industrial processes, flocculated suspensions are subjected to high shear forces [10]. Under these shear conditions, the initial flocs are usually broken up but the suspension partially reflocculates when the shear forces decrease [11]. The stability of the flocs depends on the nature of the interaction between particles and on the floc density [12].…”

Section: Open Accessmentioning

confidence: 99%

Using Light Scattering to Screen Polyelectrolytes (PEL) Performance in Flocculation

et al. 2011

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Flocculation of precipitated calcium carbonate (PCC) was monitored using light diffraction spectroscopy (LDS). Four cationic polyacrylamides of high molar mass and with different degrees of branching, all copolymers of acrylamide (AM) and acryloyloxyethyltrimethyl ammonium chloride (Q9), were tested. LDS supplied information about the kinetic curves for flocs growth and also for the flocs structure evolution. Flocculation kinetics, flocs size and structure, flocs resistance and reflocculation capacity could be correlated with the degree of branching of the polyelectrolytes (PEL). Furthermore, PEL with different degrees of branching corresponded to different values for the intrinsic viscosity, indicating differences in the polymer conformation, which explained well the performance differences in flocculation.

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Flocculation and reflocculation of clay suspension by different polymer systems under turbulent conditions

Cited by 116 publications

References 10 publications

Characterization of kaolin flocs formed by polyacrylamide as flocculation aids

Characterization of kaolin flocs formed by polyacrylamide as flocculation aids

Utilizing Cellulose Nanofibril as an Eco-Friendly Flocculant for Filler Flocculation in Papermaking

Using Light Scattering to Screen Polyelectrolytes (PEL) Performance in Flocculation

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