Continuous Thickening of Homogeneous Flocculated Slurries

Yoshioka, Naoya; Hotta, Yutaka; Tanaka, Susumu; Naito, Satoru; Tsugami, Shinichi

doi:10.1252/kakoronbunshu1953.21.66

Cited by 85 publications

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“…Although Kynch's theory can not be regarded as an appropriate model for f locculent suspensions, thickener manufacturers still use and recommend Talmage and Fitch's method, which is based on this theory, for design calculations (Outukumpu Mintec 1997). Yoshioka et al (1957) and Hassett (1958Hassett ( , 1964Hassett ( , 1968 used the solid flux density function to interpret the operation of a continuous thickener and devise a method for thickener design (see Concha and Barrientos (1993) for details).…”

Section: Theor Y Of Sedimentation (1950-1970)mentioning

confidence: 99%

“…Experience by several authors, including Yoshioka et al (1957), Hassett (1958Hassett ( , 1964Hassett ( , 1968, Shannon et al (1963), Tory and Shannon (1965), Tory (1965, 1966) and Scott (1968a,b), demonstrated that while Kynch's theory accurately predicts the sedimentation behaviour of suspensions of equally sized small rigid spherical particles, this is not the case for f locculent suspensions forming compressible sediments.…”

Section: Theor Y Of Sedimentation (1950-1970)mentioning

confidence: 99%

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A Century of Research in Sedimentation and Thickening

Concha

Bürger

2002

KONA

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Section: Theor Y Of Sedimentation (1950-1970)mentioning

confidence: 99%

Section: Theor Y Of Sedimentation (1950-1970)mentioning

confidence: 99%

A Century of Research in Sedimentation and Thickening

Concha

Bürger

2002

KONA

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“…Montgomery developed procedures for containment area design and evaluation based on the works of Coe and Clevenger (1916), McLaughlin (1959), Thackston (1972), Dick and Ewing (1967), Yoshioka et al (1957), andVesilind (1968). The testing and design procedures for flocculent settling proposed by…”

Section: Development Of Design Proceduresmentioning

confidence: 99%

Dredging Operations Technical Support Program: Verification of Procedures for Designing Dredged Material Containment Areas for Solids Retention.

Averett¹,

Palermo²,

Wade³

1988

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“…A much simpler derivation is due to Yoshioka et al ( 1957). The velocity of settling solids past a reference level has two components: the settling rate u of the solids with respect to the sedimenting suspension, and the velocity u of the suspension downward past the reference level.…”

Section: Continuous Thickeningmentioning

confidence: 99%

Sedimentation of flocculent suspensions: State of the art

Fitch

1979

AIChE Journal

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Three modes or types of sedimentation are recognized in flocculent suspensions: Clarification, in which floccules are separated and settle independently; zone settling, in which floccules are incorporated into some solids structure so that all are constrained to subside at more or less the same rate; and compression or compaction, in which the solids structure is strong enough to exhibit a compressive yield value. Current models for sedimentation in the three moses are reviewed, with particular emphasis on their use thickening presented in the literature derive from a basic partial differential equation for force balance. Models differ in which terms of the equation are disregarded. Several of the theories of compaction are essentially equivalent solutions for the same model, but with different sets of independent variables. and reliability (or lack of it) for sedimentation basin design. Most models ofSedimentation is here defined as the entire process by which particles settle out of fluid suspension. All steps of the process are profoundly affected by interfacial phenomena. Van der Waals or London forces, if not overpowered by electrostatic repulsions (zeta potentials) or fluid-dynamic shear, cause particles to cohere on contact. This gives rise to three different modes or regimes of sedimentation. Which one is followed depends upon the solids concentration, and on the relative tendency of the particles to cohere. The factors are important because they correspond to different sedimentation models or mechanisms.Types of sedimentation are represented paragenetically in Figure 1. The left side represents particles with little tendency to cohere; the right side, those for which interparticle cohesion is strong. The vertical axis represents particle concentration, with more concentrated suspensions at the top.At low concentrations, there occurs a regime called clarification. Particles are, on the average, far apart and free to settle independently, but collisions occur. If the particles then cohere, they grow into clumps, or floccules, whose settling rate increases as they grow. If, on the other hand, they do not cohere, each bumps downward at its characteristic rate. Thus there are two types of settling in clarification: flocculent, and particulate. There is no sharp boundary between the two; one grades gradually into the others. And, it is common practice to modify behavior in this regime by adding flocculants to aid clarification.Clarification behavior is easily recognized in a batch test. Slower settling particles string out behind faster settling ones. The upper layers gradually thin out, or clarify, Settled solids collect at the bottom in a layer whose upper boundary rises as solids settle into it.As particles become more concentrated, crowded closer together, they Enally reach a point where each is in contact with others. If they then have any tendency to cohere, they link into some sort of floc structure. Whether the structure formed is continuous (Fitch 1982(Fitch , 1972 consists of a bed of closely-spaced...

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Continuous Thickening of Homogeneous Flocculated Slurries

Cited by 85 publications

References 0 publications

A Century of Research in Sedimentation and Thickening

A Century of Research in Sedimentation and Thickening

Dredging Operations Technical Support Program: Verification of Procedures for Designing Dredged Material Containment Areas for Solids Retention.

Sedimentation of flocculent suspensions: State of the art

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