Influence of hydrolyzable metal ions on the interfacial chemistry, particle interactions, and dewatering behavior of kaolinite dispersions

Mpofu, Patience; Addai‐Mensah, Jonas; Ralston, John

doi:10.1016/s0021-9797(03)00113-9

Cited by 107 publications

(65 citation statements)

References 23 publications

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“…In particular, the reduction is sharp for pH higher than 9. Calcium undergoes hydrolysis at higher pH (pH > 10) leading to the formation of monovalent species [33,34]. According to [14], the observed behaviour can be linked to the formation and specific adsorption of first hydrolysis product of calcium (i.e.…”

Section: Resultsmentioning

confidence: 99%

Chemo-physical evolution and microstructure features of lime treated soils

Russo

2016

E3S Web Conf.

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Abstract. In the paper some results on the effects of chemo-physical evolution of clay-lime-water suspensions on the microstructure of a lime treated kaolin have been presented. A multi-scale investigation on the sedimentation behaviour of clay suspensions under different pore water chemistry has been developed highlighting the chemophysical mechanisms controlling particle arrangement and the soil fabric formation. The results evidenced the key role of ionic exchange in the short term on the microstructure features of the lime treated soil.

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Section: Resultsmentioning

confidence: 99%

Chemo-physical evolution and microstructure features of lime treated soils

Russo

2016

E3S Web Conf.

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“…The suspension's dewatering behaviour was assessed by following the mud-line movement -time measurement procedure as described in previous studies. [4,15] The effect of shear on consolidation of pre-sedimented pulps was examined at an agitation rate of 250 rpm for 15 min using a four-blade turbine impeller. For sediment yield stress measurement, the vane technique (Haake VT 550) was used in the manner of a procedure described by McFarlane et al .…”

Section: Experimental Methodsmentioning

confidence: 99%

Polyelectrolyte enhanced flocculation, particle interactions and dewaterability of fine gibbsite dispersions

Addai‐Mensah

Bal

Yeap

2008

Asia-Pacific J Chem Eng

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Enhanced dewaterability of colloidal hydrophilic mineral dispersions, via flocculation and gravity-assisted thickening, remains an important and technically challenging issue. To develop the right customized approach for flocculant selection to improve dewaterability, the influence of eight polyacrylamide (PAM) copolymers on flocculation, particle interactions and dewatering behaviour of fine, 9.5 wt% gibbsite dispersions at pH 7.5, 9.5 and 11.5 at 22• C is investigated. The results show that polymer charge type (anionic vs cationic) and charge density (5-45%) and molecular weight [(5-20) × 106 Da] had a striking, pH-dependent impact on dewaterability and dispersion rheology. Depending upon polymer type and dosage (50-200 g t −1 solid) and pulp pH, good to extremely fast settling rates (14-200 m h −1 ) were obtained upon orthokinetic flocculation. Sediment solid loadings recorded also showed polymer structure-and pH-dependency and were in the range 40-54 wt%. Upon shear of the pre-sedimented pulps, a 6-10 wt% solid improvement in consolidation resulted. The polymer with lower charge density (5% anionic) and lower molecular weight [(5-10) × 106 Da] was more effective in producing enhanced dewaterability of charged and neutral gibbsite particles than the polymers with higher molecular weights and/or charges. The settling rate, sediment consolidation and particle interactions (rheology) correlated positively, where faster settling flocs displayed higher sediment yield stresses which were accompanied by greater compaction behaviour. The findings underscore the need for greater understanding of the interplay between pulp interfacial chemistry and flocculant characteristics for optimum dewaterability.  2008

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“…For high molecular weight polymers, bridging is usually the dominant mechanism of flocculation, not charge neutralisation, therefore it may not be necessary for the polymer to have a high charge density. Calcium chloride dihydrate, CaCl 2 .2H 2 O (molecular mass 147.02), supplied by Fluka Chemika, was added to the suspensions to induce flocculation by salt bridging (17); previous work has also suggested better flocculation performance in the presence of a combination of metal ions and flocculants (18). Double distilled deionised water was used to make up the suspensions.…”

Section: Materials and Experimental Setupmentioning

confidence: 99%

Effect of Flocculation on Critical Flux during Crossflow Microfiltration of Bentonite Suspensions

Chellappah

Tarleton

Wakeman

2008

Separation Science and Technology

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The effectiveness of polymeric flocculant addition and hydrodynamics on increasing the critical permeation flux, J crit , during crossflow microfiltration of bentonite suspensions using a tubular ceramic membrane module was investigated. The investigation determined the effects of flocculant concentration on J crit at various crossflow velocities. The best filtration performance (highest J crit ) was obtained at a flocculant dose of 500 mg kg -1 (mg of flocculant per kg of solids) and at a crossflow velocity of 1.71 m s -1. Particle size has been used as a parameter to fit the shear-induced hydrodynamic diffusion model to the experimental filtration data.

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Influence of hydrolyzable metal ions on the interfacial chemistry, particle interactions, and dewatering behavior of kaolinite dispersions

Cited by 107 publications

References 23 publications

Chemo-physical evolution and microstructure features of lime treated soils

Chemo-physical evolution and microstructure features of lime treated soils

Polyelectrolyte enhanced flocculation, particle interactions and dewaterability of fine gibbsite dispersions

Effect of Flocculation on Critical Flux during Crossflow Microfiltration of Bentonite Suspensions

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