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Article

Estimating the Shear Resistance of Flocculated Kaolin Aggregates: Effect of Flocculation Time, Flocculant Dose, and Water Quality

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Departamento de Ingeniería Química y Procesos de Minerales, Facultad de Ingeniería, Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1240000, Chile
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Faculty of Engineering and Architecture, Universidad Arturo Prat, Almirante Juan José Latorre 2901, Antofagasta 1244260, Chile
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Department of Metallurgical and Mining Engineering, North Catholic University, Angamos Av. 0610, Antofagasta 1270709, Chile
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Escuela de Ingeniería Química, Pontificia Universidad Católica de Valparaíso, Valparaíso 2340000, Chile
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Departamento de Química, Facultad de Ciencias, Universidad del Bio Bio, Av. Collao 1202, Concepción 4030000, Chile
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Department of Chemical Engineering and Laboratory of Surface Analysis (ASIF), Universidad de Concepcion, P.O. Box 160-C, Correo 3, Concepción 4030000, Chile
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Author to whom correspondence should be addressed.
Academic Editors: Beata Podkościelna and Andrzej Puszka
Polymers 2022, 14(7), 1381; https://doi.org/10.3390/polym14071381
Received: 21 February 2022 / Revised: 14 March 2022 / Accepted: 15 March 2022 / Published: 29 March 2022
(This article belongs to the Special Issue Synthesis, Processing, Structure and Properties of Polymer Materials)
The resistance of kaolin aggregates to shearing in water clarification and recovery operations is a critical input in designing thickener feed wells. A recently formulated but already available criterion is used to determine the shear strength of flocculated kaolin aggregates. The flocculant is a high molecular weight anionic polyelectrolyte. The resistance of the aggregates is evaluated as a function of flocculation time, flocculant dosage, and water quality. The determination is based on a standardized experimental method. First, the time evolution of the average size of kaolin flocs is measured when aggregates are exposed to incremental shear rates from a predetermined base value. Then, the results are fitted to a pseudo-first-order model that allows deriving a characteristic value of the shear rate of rupture associated with the upper limit of the strength of the aggregates. In seawater, at a given dose of flocculant, the strength of the aggregates increases with time up to a maximum; however, at longer times, the resistance decreases until it settles at a stable value corresponding to stable aggregates in size and structure. A higher flocculant dosage leads to stronger aggregates due to more bridges between particles and polymers, leading to a more intricate and resistant particle network. In industrial water with very low salt content, the resistance of the kaolin aggregates is higher than in seawater for the same dose of flocculant. The salt weakens the resistance of the aggregates and works against the efficiency of the flocculant. The study should be of practical interest to concentration plants that use seawater in their operations. View Full-Text
Keywords: kaolin flocculation; aggregate resistance; salinity; flocculation kinetic; shear rate kaolin flocculation; aggregate resistance; salinity; flocculation kinetic; shear rate
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MDPI and ACS Style

Pérez, K.; Toro, N.; Jeldres, M.; Gálvez, E.; Robles, P.; Alvarado, O.; Toledo, P.G.; Jeldres, R.I. Estimating the Shear Resistance of Flocculated Kaolin Aggregates: Effect of Flocculation Time, Flocculant Dose, and Water Quality. Polymers 2022, 14, 1381. https://doi.org/10.3390/polym14071381

AMA Style

Pérez K, Toro N, Jeldres M, Gálvez E, Robles P, Alvarado O, Toledo PG, Jeldres RI. Estimating the Shear Resistance of Flocculated Kaolin Aggregates: Effect of Flocculation Time, Flocculant Dose, and Water Quality. Polymers. 2022; 14(7):1381. https://doi.org/10.3390/polym14071381

Chicago/Turabian Style

Pérez, Kevin, Norman Toro, Matías Jeldres, Edelmira Gálvez, Pedro Robles, Omar Alvarado, Pedro G. Toledo, and Ricardo I. Jeldres. 2022. "Estimating the Shear Resistance of Flocculated Kaolin Aggregates: Effect of Flocculation Time, Flocculant Dose, and Water Quality" Polymers 14, no. 7: 1381. https://doi.org/10.3390/polym14071381

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