Rheological and Solid–Liquid Separation Properties of Bimodal Suspensions of Colloidal Gibbsite and Boehmite

Bruinsma, Paul J.; Wang, Yong; Li, X.Shari; Li, Jun; Smith, Peter A.; Bunker, Bruce C.

doi:10.1006/jcis.1997.5013

Cited by 9 publications

(6 citation statements)

References 13 publications

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“…Similar results were recently observed by Bruinsma and coworkers, 15 who studied the rheology and sedimentation of mixtures of nano-boehmite particles and large gibbsite particles (particles with similar iep's). It was found that the nano-boehmite particles would adsorb on the larger gibbsite particles even when the sign of the surface charge was the same for both.…”

Section: Introductionsupporting

confidence: 89%

“…Slurries consisting of nanoparticles and larger, submicrometer or micrometer particles have recently been studied. [13][14][15] Shih and co-workers studied the rheology and consolidation behavior of colloidal silicon nitride suspensions (0.74 m) with nanosized (20 nm diameter) alumina particles. 14 At a pH where the silicon nitride particles were positively charged and the alumina negatively charged, the viscosity of the mixture first increased and then decreased with an increasing volume fraction of the alumina powder.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Silica Nanoparticle Size on the Stability of Alumina/Silica Suspensions

Fisher

Čolić

Rao

et al. 2001

Journal of the American Ceramic Society

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The influence of the addition of silica particles (5, 15, 25, and 300 nm) on the zeta potential and viscosity of aqueous alumina slurries (250 nm particles) was investigated in a pH range where the surface charge was positive for alumina and negative for silica. For slurries formulated with the smaller silica particles, the isoelectric point shifted from pH 9.0 to pH Ϸ3 (depending on the particle size of the silica) with increasing volume fraction of silica particles. At pH 9, the original isoelectric point for the alumina alone, these mixed slurries had a shear-rate-independent, low viscosity (Newtonian behavior). Both of these results show that the smaller (<25 nm) silica particles adsorb to the surface of alumina. The fraction of silica adsorbed to the alumina surface was dependent on the size of the silica particles, and was consistent with surface coverage calculations based on the effect of surface curvature on the limits of dense random parking. The larger silica particles (300 nm) could not physically cover the surface of the alumina particles, and simply formed a mixed, attractive particle network that exhibited a much higher viscosity with non-Newtonian (viz., shear rate thinning) behavior.

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Section: Introductionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Effect of Silica Nanoparticle Size on the Stability of Alumina/Silica Suspensions

Fisher

Čolić

Rao

et al. 2001

Journal of the American Ceramic Society

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“…In the mixing process, the nano-particles prefer to collide with micro-particles, 18 which can be further driven by repulsive interactions between the nanoparticles which are highly positively charged (ξ = 35.5 mV) plus a weak attraction between the neutral micro-particles and the nano-particles. 19 As a result, the nano-particles form a coating layer on the surface of micro-particles and the average particle size increases, resulting in low viscosity.…”

Section: Rheological Behaviourmentioning

confidence: 99%

Drying stress of yttria-stabilized-zirconia slurry on a metal substrate

Lan

Xiao

2007

Journal of the European Ceramic Society

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“…Colloidal boehmite prepared by peptization of boehmite with mineral acid has been widely used for the fabrication of ceramic powders, − hollow microspheres, porous membranes, dispersants, , and photoluminescent and mesoporous alumina, , pollution control, separation technology, , paste, and so on. As a matrix and binder of a fluid catalytic cracking (FCC) catalyst, peptized boehmite can promote its catalytic activity for gas oil and residual oil cracking. , In 2008, the catalytic cracking capacity was up to 600 million tons/year, which is about 23% of the total refining capacity in the petroleum industry .…”

Section: Introductionmentioning

confidence: 99%

Peptization Mechanism of Boehmite and Its Effect on the Preparation of a Fluid Catalytic Cracking Catalyst

Zheng

Song

et al. 2014

Ind. Eng. Chem. Res.

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A peptization mechanism of boehmite was proposed in this work. The effects of peptization on the properties and performances of a fluid catalytic cracking (FCC) catalyst were explored. A boehmite colloid was prepared through peptization of boehmite with hydrochloric acid, and its particle size distribution was characterized during peptization. With an increase of the acid/alumina molar ratio from 0 to 0.11, the particle size of the boehmite colloid decreased to 3.5 nm. The particle size increased from 3.5 to 11 nm when the acid/alumina molar ratio was further increased to 0.16 and remained at 10 nm thereafter. The smallest dispersed boehmite particles were obtained in an acid/alumina molar ratio of 0.11. On the basis of many experiments, the dispersion and coalition mechanisms of boehmite during acid peptization were proposed. Boehmite particles absorb protons on the surface hydroxyl groups and repel each other to form colloidal particles when the acid/aluminia ratio is low. With more hydrochloric acid added, large amounts of chloride anions cause compression of the boehmite diffuse layer, thus resulting in boehmite coalition. A FCC catalyst was prepared by peptizing boehmite with an acid/alumina molar ratio of 0.11. The catalyst has a larger external surface area, a higher mesoporous volume, and better acidity distribution than the catalyst prepared with boehmite. Both conversion of residue oil and yields of diesel and gasoline over a peptized catalyst are higher than those over the catalyst without being peptized.

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Rheological and Solid–Liquid Separation Properties of Bimodal Suspensions of Colloidal Gibbsite and Boehmite

Cited by 9 publications

References 13 publications

Effect of Silica Nanoparticle Size on the Stability of Alumina/Silica Suspensions

Effect of Silica Nanoparticle Size on the Stability of Alumina/Silica Suspensions

Drying stress of yttria-stabilized-zirconia slurry on a metal substrate

Peptization Mechanism of Boehmite and Its Effect on the Preparation of a Fluid Catalytic Cracking Catalyst

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