This project investigated the viscosity of heavy medium suspensions. Heavy medium suspensions are used extensively in the minerals processing industry for separation of valuable materials from gangue on the basis of density. Rheological profiles for ferrosilicon and magnetite suspensions were determined using a laboratory-scale viscometer developed in the School of Chemical Engineering, University of KwaZulu-Natal, Howard College Campus, Durban. Ferrosilicon suspensions with specific gravities ranging from 2.0-3.2 were investigated in the presence of clay, to simulate higher density separations such as those used in the diamond industry, where slime build up can be a problem. Magnetite suspensions were prepared at specific gravities ranging from 1.6 - 2.6 to simulate separation densities used in the coal cleaning industry. Mixtures of suspensions of fine magnetite, and coarse magnetite, were also prepared to see what the effect of a coarser medium would have on the viscosity of the suspensions. The effect of viscosity on the separation efficiency of heavy medium separations was also investigated, using a laboratory-scale Dense Medium Separator designed and developed in the department. Suspensions with specific gravities between 1.6 and 1.8 were used to separate coal samples in the following size ranges: - 4mm + 1mm; -1mm + 500um; and -4mm + 500um. The rheograms for ferrosilicon suspensions showed that at low shear rates the suspensions behaved as pseudo-plastic liquids, while at high shear rates the behaviour resembled that of dilatant fluids. At low specific gravities the behaviour of magnetite suspensions was pseudo Newtonian. For specific gravities greater than 2.0, the suspensions became pseudo-plastic. The effect of a locally available dispersant (DP001), on the viscosity of the heavy medium suspensions, was also investigated. For ferrosilicon / clay mixtures, a reduction in viscosity of up to 20 percent was achievable for some specific gravities and slimes level. It was also observed that the dispersant had little effect or none at all, on the viscosity of uncontaminated ferrosilicon suspensions. Addition of the dispersant to fine magnetite suspensions achieved viscosity reductions between 8 and 10 percent. It was observed that the presence of coarse magnetite reduced the viscosity of fine magnetite suspensions by as much as 40 % at certain coarser solid ratios. Adsorption tests using a UV spectrometer showed that there was little or no DP001 adsorbed onto the surfaces of uncontaminated ferrosilicon particles. The results showed that DP001 was adsorbed onto the surfaces of magnetite #1 particles, with almost half the amount of 1 g DP001 / kg Mag #1 added to a test suspension of specific gravity 2.2 being adsorbed. This explained why magnetite #1suspensions were more susceptible to DP001 addition compared to ferrosilicon suspensions. For some of the coal size ranges separated, it was observed that there was a reduction of approximately 22% in the separation efficiency of the process as the specific gravity was increased. For some of the coal samples, an improvement in separation efficiency between 11% and 17% was achievable with DP001 additions of Ig DP001/kg solids, and 2g DP001/kg solids. The presence of coarse magnetite media initially improved the separation efficiency by up to 50% for some coal samples. However, as DP001 was added, there was a decline in the separation efficiency. In conclusion, the measured rheological profiles of the suspensions were comparable with those found in literature. It was shown that media particle size distribution affects the viscosity of heavy medium suspensions. It was also shown that surface active agents can be used to reduce the viscosity of heavy medium suspensions. / Thesis (M.Sc.Eng)-University of KwaZulu-Natal, 2005.

Yam Chi Tong = 懸浮顆粒之介電反應 / 任智堂. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 76-79). / Text in English; abstracts in English and Chinese. / Yam Chi Tong = xuan fu ke li zhi jie dian fan ying / Ren Zhitang. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Spectral Representation of a Pair of Polydisperse Cylinders --- p.3 / Chapter 2.1 --- Introduction --- p.3 / Chapter 2.2 --- Multiple Image Method --- p.4 / Chapter 2.2.1 --- Polydispersity in Size --- p.6 / Chapter 2.2.2 --- Polydispersity in Permittivity --- p.7 / Chapter 2.3 --- Spectral Representation --- p.9 / Chapter 2.3.1 --- Polydisperse Size Cylinders --- p.10 / Chapter 2.3.2 --- Polydisperse Permittivity Cylinders --- p.12 / Chapter 2.4 --- Numerical Results --- p.13 / Chapter 2.4.1 --- Polydispersity in Size --- p.14 / Chapter 2.4.2 --- Polydispersity in Permittivity --- p.17 / Chapter 2.5 --- Conclusion --- p.22 / Chapter 3 --- Dielectric Behaviors of Polydisperse Colloidal Suspensions --- p.24 / Chapter 3.1 --- Introduction --- p.24 / Chapter 3.2 --- Dielectric Dispersion Spectral Representation --- p.26 / Chapter 3.3 --- Polydisperse Colloidal Suspensions --- p.28 / Chapter 3.4 --- Numerical Results --- p.30 / Chapter 3.4.1 --- Monodisperse Limit --- p.31 / Chapter 3.4.2 --- Influence of the Medium Conductivities --- p.32 / Chapter 3.4.3 --- Effect of Conductivity Contrasts --- p.34 / Chapter 3.4.4 --- Effect of Varying the Volume Fractions --- p.37 / Chapter 3.5 --- Conclusion --- p.41 / Chapter 4 --- Dielectric Behaviors of Shelled Cell Suspensions --- p.43 / Chapter 4.1 --- Introduction --- p.43 / Chapter 4.2 --- Shelled Spherical Particle Model --- p.46 / Chapter 4.2.1 --- Intrinsic Dispersions --- p.47 / Chapter 4.3 --- Numerical Results --- p.49 / Chapter 4.3.1 --- One Type of Shelled Cells --- p.51 / Chapter 4.3.2 --- Mixture of Two Types of Shelled Cells --- p.60 / Chapter 4.4 --- Conclusion --- p.62 / Chapter 5 --- Dielectric Behaviors of Compositionally Graded Films --- p.64 / Chapter 5.1 --- Introduction --- p.64 / Chapter 5.2 --- Discrete Layer Model --- p.65 / Chapter 5.2.1 --- Linear Profiles --- p.67 / Chapter 5.2.2 --- Gaussian Profiles --- p.67 / Chapter 5.3 --- Continuously Graded Model --- p.68 / Chapter 5.3.1 --- Linear Profiles --- p.68 / Chapter 5.3.2 --- Gaussian Profiles --- p.69 / Chapter 5.4 --- Conclusion --- p.72 / Chapter 6 --- Summary --- p.74 / Bibliography --- p.76 / Chapter A --- The Maxwell-Garnett Approximation --- p.80 / Chapter B --- The Bergman-Milton Spectral Representation --- p.82

Huang Ji Ping. / "1st June, 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (p. 125-134). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Wong Chiu Tai, Andrew = 粒子懸浮液的自結合和場引發結合 / 黃昭泰. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 70-73). / Text in English; abstracts in English and Chinese. / Wong Chiu Tai, Andrew = Li zi xuan fu ye de zi jie he he chang yin fa jie he / Huang Zhaotai. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Self assembly --- p.1 / Chapter 1.1.1 --- What is self assembly? --- p.1 / Chapter 1.1.2 --- Recent works --- p.1 / Chapter 1.2 --- Field induced assembly --- p.2 / Chapter 1.2.1 --- What is field induced assembly? --- p.2 / Chapter 1.2.2 --- Recent works --- p.3 / Chapter 1.3 --- Objective of the thesis --- p.4 / Chapter 2 --- Self Assembly of Binary Colloidal Alloys --- p.6 / Chapter 2.1 --- Interaction between colloidal suspensions --- p.7 / Chapter 2.1.1 --- Van der Waals interaction energy between two spheres --- p.7 / Chapter 2.1.2 --- Screened Coulomb Repulsion --- p.9 / Chapter 2.1.3 --- Derjaguin-Landau-Verwey-Overbeek potential --- p.12 / Chapter 2.1.4 --- DNA-mediated Colloidal Interaction --- p.13 / Chapter 2.2 --- 2D Molecular Dynamics Simulation --- p.14 / Chapter 2.2.1 --- One type of particles with attractive force --- p.16 / Chapter 2.2.2 --- Two type of particles --- p.18 / Chapter 2.2.3 --- Results --- p.19 / Chapter 2.2.4 --- Conclusion --- p.23 / Chapter 2.3 --- 3D Molecular Dynamics Simulation --- p.25 / Chapter 2.3.1 --- One type of particles with attractive force --- p.26 / Chapter 2.3.2 --- Two type of particles --- p.27 / Chapter 2.3.3 --- Results --- p.28 / Chapter 2.3.4 --- Conclusion --- p.32 / Chapter 3 --- Electrorheological Rotors --- p.34 / Chapter 3.1 --- Formalism --- p.35 / Chapter 3.2 --- MD Simulations and Results --- p.38 / Chapter 3.3 --- Discussion and conclusion --- p.39 / Chapter 4 --- Electrorheological Suspensions in Rotating Fields --- p.42 / Chapter 4.1 --- Long-range rotating field simulation --- p.43 / Chapter 4.1.1 --- Simulation method --- p.43 / Chapter 4.1.2 --- Result --- p.46 / Chapter 4.2 --- Uniform Rotating Shear Flow --- p.49 / Chapter 4.3 --- Discussion and conclusion --- p.50 / Chapter 5 --- Comparison between many body and multiple image effect --- p.53 / Chapter 5.1 --- Multiple image method --- p.54 / Chapter 5.2 --- Anisotropic many-body-MID model --- p.56 / Chapter 5.3 --- Computer simulation in the many-body-DID model --- p.59 / Chapter 5.4 --- Discussion and conclusion --- p.60 / Chapter 6 --- Conclusion --- p.68 / Bibliography --- p.70 / Chapter A --- Derivation of multiple image expression --- p.74 / Chapter A.1 --- Image of a point dipole on a sphere --- p.74 / Chapter A.2 --- Multiple images of induced dipole --- p.74 / Chapter B --- Derivation of anisotropic Maxwell-Garnett Approximation --- p.80 / Chapter B.1 --- Isotropic Maxwell-Garnett Approximation --- p.80 / Chapter B.2 --- Anisotropic Maxwell-Garnett Approximation --- p.82

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Bibliography: leaves 288-296. / by Steven Minh Dinh. / Sc.D.

Multiphase systems (containing solid, liquid and gas) are increasingly common in a number of industries, with the most complex manifestation being three-phase froth. The interstitial suspension has to navigate tortuous channels and its transport is affected by drag, capillary and gravitational forces. Particle properties such as wettability, size, shape, and morphology results in a number of different types of interactions with the liquid-air interface and can have a significant effect on froth composition and stability. The effect of particle size and shape on its transport through these confined channels is thus of great interest for a number of industrial applications and is the focus of this work. This transport behavior is studied using a three phase transient froth that is produced in the froth flotation process for mineral separation. In this system, hydrophilic non-value particles present in the interstitial liquid phase do not attach to air bubbles, and their removal is desirable. The original hypothesis was that as particles become more anisotropic in shape, there is an increase in the froth interstitial viscosity, which results in reduced drainage rate of particles through the froth. Flotation experiments, froth sampling experiments, and rheological experiments were conducted to test this hypothesis. Froth zone sampling experiments were conducted using mixtures of sized platy mica, needle-like wollastonite, and fibrous chrysotile, all mixed with low aspect ratio silica in varying amounts. The froth zone suspension compositions were then used to prepare the froth interstitial suspension ex-situ, and bulk rheological measurements were conducted on the suspensions. The data showed that while the relative viscosities of the suspensions were much higher at even low concentrations of the fibrous ore in the mixture, there was no significant difference when mica was substituted for silica in the mixture at high concentrations (~50 wt%) at the solids volume fraction of interest (~7.5%). The bulk rheological measurements thus could not fully account for the difference in transport behavior between mica and silica. Flotation experiments were conducted with a copper mineral-containing ore augmented with additional hydrophilic minerals mica, silica (low aspect ratio), wollastonite or chrysotile. The results suggest increasing aspect ratios of the added non-value particles result in increased net transport (transport accounting for loss due to drainage) through the froth zone; mica transport is faster than silica. Froth zone sampling experiments (using pure mixtures of above minerals) confirmed that mica net transport was greater than that of silica. It was then hypothesized that this increase was due to increased drag experienced by high aspect ratio mica compared to low aspect ratio silica. The doped ore flotation data also suggested a decrease in transport as size of added platy mica increased until a local transport minimum was reached, beyond which another increase in transport was observed. It was further hypothesized that this was related to confinement of coarse mica particles in the plateau borders when the size of the constriction was comparable to particle size. Froth sampling experiments under high drag (upward flow dominated) conditions were compared with those under conditions where drag and drainage were more balanced (steady state froths). Under high drag conditions, mica mixtures showed more hydrophilic mineral mass in the froth zone compared to silica mixtures. Under drag and drainage-balanced conditions when the size of mica approached the size of the measured channel size, platy mica was found to be accumulating in the froth. This was not the case for silica particles with settling being more efficient for silica than for mica. The key parameters driving transport of particles through the froth are the bulk rheology of the interstitial suspension (driven by particle size and shape distributions and solids concentration), the size of constrictions in the plateau borders and vertices and the resulting confinement effects, and the mobility or elasticity of the interfaces (driven largely by the hydrophobic particles attached at the interface).

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains ix, 110 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 54-59).

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Sulfuric acid hydrolysis of native cellulose fibers produces stable suspensions of cellulose nanocrystals. Within a specific concentration range, the suspensions spontaneously form an anisotropic chiral nematic liquid crystal phase. This thesis examines the phase separation behaviour of these suspensions, alone and in the presence of added macromolecules. Initially, the effect of hydrolysis conditions on the nanocrystal and phase separation properties for hydrolyzed softwood pulp were investigated and compared to suspensions prepared from hardwood pulp. The macromolecules studied, blue dextrans of varying molecular weights and dye ligand densities, were synthesized and characterized with a number of techniques. The polyelectrolytic nature of these macromolecules was found to strongly influence their physico-chemical properties. Added blue dextran causes separation of an isotropic phase from highly concentrated, completely anisotropic suspensions. The observed phase separation was found to be associated with the charged dye molecules attached to the dextran. The partitioning behaviour of blue dextrans in biphasic aqueous suspensions of native cellulose nanocrystals was also studied with regard to the effect of total concentration of blue dextran, degree of dye substitution and dextran molecular weight on the blue dextran partition coefficient. Electrostatic and entropic contributions to the partition coefficient of blue dextran were discussed. Triphase isotropic-isotropic-nematic (I1--I 2--N) equilibria are observed in suspensions containing both neutral dextrans and polyelectrolytic blue dextrans of varying molecular weight. Based on these results, phase diagrams for cellulose nanocrystal suspensions with different combinations of dextran and blue dextran are presented.