Settleability Testing and Settling Rate

2003 ◽  
pp. 147-150
Keyword(s):  
Settling Rate

Accurate, fully automated determination of the initial settling rate of flocculated suspensions

2021 ◽  
Vol 164 ◽  
pp. 106823
Author(s):  
Cuong V. Nguyen ◽  
Emma Dinh ◽  
Andrew Doi ◽  
Thuong V. Nguyen ◽  
Anh V. Nguyen
Keyword(s):  
Settling Rate ◽  
Automated Determination

scholarly journals Using Specified Risk Materials-Based Peptides for Oil Sands Fluid Fine Tailings Management

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1582
Author(s):  
Yeling Zhu ◽  
Yuki Gong ◽  
Heather Kaminsky ◽  
Michael Chae ◽  
Paolo Mussone ◽  
...  
Keyword(s):  
Oil Sands ◽  
Colloidal Stability ◽  
Free Water ◽  
Value Added ◽  
Settling Rate ◽  
Test Range ◽  
Tailings Management ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
Hydrolyzed Polyacrylamide

Fluid fine tailings are produced in huge quantities by Canada’s mined oil sands industry. Due to the high colloidal stability of the contained fine solids, settling of fluid fine tailings can take hundreds of years, making the entrapped water unavailable and posing challenges to public health and the environment. This study focuses on developing value-added aggregation agents from specified risk materials (SRM), a waste protein stream from slaughterhouse industries, to achieve an improved separation of fluid fine tailings into free water and solids. Settling results using synthetic kaolinite slurries demonstrated that, though not as effective as hydrolyzed polyacrylamide, a commercial flocculant, the use of SRM-derived peptides enabled a 2-3-fold faster initial settling rate than the blank control. The pH of synthetic kaolinite tailings was observed to be slightly reduced with increasing peptides dosage in the test range (10–50 kg/ton). The experiments on diluted fluid fine tailings (as a representation of real oil sands tailings) demonstrated an optimum peptides dosage of 14 kg/ton, which resulted in a 4-fold faster initial settling rate compared to the untreated tailings. Overall, this study demonstrates the novelty and feasibility of using SRM-peptides to address intractable oil sands fluid tailings.

scholarly journals Exploratory study to assess the impact of chitosan /bentonite ratio on the metal removal capacity of chitosan modified bentonite clay

2016 ◽  
Vol 18 (2) ◽  
pp. 437-443 ◽  
Keyword(s):  
Physical Properties ◽  
Adsorption Capacity ◽  
Adsorption Isotherms ◽  
Exploratory Study ◽  
Metal Removal ◽  
Bentonite Clay ◽  
Settling Rate ◽  
Modified Bentonite ◽  
Removal Capacity ◽  
The Impact

<div> <p>Adsorption is one of the methods that can be used for metal removal. In this study five metals were used cadmium, chromium, lead, copper and Nickel (Cd, Cr, Pb, Cu, and Ni) over a concentration range from 0.8 to about 7 mg l<sup>-1</sup> for each metal. Adsorbents were prepared with increasing chitosan to bentonite ratio from 0 to 0.67 g chitosan/g bentonite. The study showed that adsorption of metals on plain bentonite and chitosan modified bentonite can fit well with Langmuir and Freundlich adsorption isotherms. Furthermore, the bentonite adsorption capacity will decrease with the increase of chitosan/bentonite ratio. This study concluded that bentonite is a good adsorbent. However, the applicability of bentonite as potential adsorbent may be limited by its physical properties such as slow settling rate and difficulty to use it as an adsorbent in adsorption columns. Despite the decrease of maximum theoretical adsorption capacity as a result of chitosan modification, the addition of small amount of chitosan can improve the physical characteristics of bentonite clay to be used as an adsorbent.&nbsp;</p> </div> <p>&nbsp;</p>

A numerical study of the nucleation, growth and settling of crystals from a turbulent convecting fluid

2021 ◽  
Author(s):  
Vojtech Patocka ◽  
Nicola Tosi ◽  
Enrico Calzavarini
Keyword(s):  
Magma Chamber ◽  
Solid Fraction ◽  
Large Scale ◽  
Solid Phase ◽  
Numerical Study ◽  
Equilibrium Concentration ◽  
Solid Particles ◽  
Settling Rate ◽  
Carrier Fluid ◽  
Nucleation Growth

&lt;p&gt;We evaluate the equilibrium concentration of a thermally convecting suspension that is cooled from above and in which&lt;br&gt;solid crystals are self-consistently generated in the thermal boundary layer near the top. In a previous study (Patoc&amp;#780;ka et&lt;br&gt;al., 2020), we investigated the settling rate of solid particles suspended in a highly vigorous (Ra = 10&lt;sup&gt;8&lt;/sup&gt; , 10&lt;sup&gt;10&lt;/sup&gt;, and 10&lt;sup&gt;12&lt;/sup&gt; ),&lt;br&gt;finite Prandtl number (Pr = 10, 50) convection. In this follow-up study we additionally employ the model of crystal&lt;br&gt;generation and growth of Jarvis and Woods (1994), instead of using particles with a predefined size and density that are&lt;br&gt;uniformly injected into the carrier fluid.&lt;/p&gt;&lt;p&gt;We perform a series of numerical experiments of particle-laden thermal convection in 2D and 3D Cartesian geometry&lt;br&gt;using the freely available code CH4 (Calzavarini, 2019). Starting from a purely liquid phase, the solid fraction gradually&lt;br&gt;grows until an equilibrium is reached in which the generation of the solid phase balances the loss of crystals due to&lt;br&gt;sedimentation at the bottom of the fluid. For a range of predefined density contrasts of the solid phase with respect to&lt;br&gt;the density of the fluid (&amp;#961;&lt;sub&gt;p&lt;/sub&gt; /&amp;#961;&lt;sub&gt;f&lt;/sub&gt; = [0, 2]), we measure the time it takes to reach such equilibrium. Both this time and&lt;br&gt;the equilibrium concentration depend on the average settling rate of the particles and are thus non-trival to compute for&lt;br&gt;particle types that interact with the large-scale circulation of the fluid (see Patoc&amp;#780;ka et al., 2020).&lt;/p&gt;&lt;p&gt;We apply our results to the cooling of a large volume of magma, spanning from a large magma chamber up to a&lt;br&gt;global magma ocean. Preliminary results indicate that, as long as particle re-entrainment is not a dominant process, the&lt;br&gt;separation of crystals from the fluid is an efficient process. Fractional crystallization is thus expected and the suspended&lt;br&gt;solid fraction is typically small, prohibiting phenomena in which the feedback of crystals on the fluid begins to govern the&lt;br&gt;physics of the system (e.g. Sparks et al, 1993).&lt;/p&gt;&lt;p&gt;References&lt;br&gt;Patoc&amp;#780;ka V., Calzavarini E., and Tosi N.(2020). Settling of inertial particles in turbulent Rayleigh-Be&amp;#769;nard convection.&lt;br&gt;Physical Review Fluids, 26(4) 883-889.&lt;/p&gt;&lt;p&gt;Jarvis, R. A. and Woods, A. W.(1994). The nucleation, growth and settling of crystals from a turbulently convecting&lt;br&gt;fluid. J. Fluid. Mech, 273 83-107.&lt;/p&gt;&lt;p&gt;Sparks, R., Huppert, H., Koyaguchi, T. et al (1993). Origin of modal and rhythmic igneous layering by sedimentation in&lt;br&gt;a convecting magma chamber. Nature, 361, 246-249.&lt;/p&gt;&lt;p&gt;Calzavarini, E (2019). Eulerian&amp;#8211;Lagrangian fluid dynamics platform: The ch4-project. Software Impacts, 1, 100002.&lt;/p&gt;

scholarly journals Settling Rate of Turkey Sperm on a Haemocytometer

1952 ◽  
Vol 31 (4) ◽  
pp. 681-684 ◽  
Author(s):  
H.J. Phillips ◽  
H.L. Wiegers
Keyword(s):  
Settling Rate

The Settling and Some Experimental Reactions of a Bryozoan Larva, Watersipora cucullata (Busk)

1958 ◽  
Vol 9 (3) ◽  
pp. 362 ◽  
Author(s):  
B Wisley
Keyword(s):  
High Mortality ◽  
Settling Rate ◽  
Sydney Harbour

The external anatomy and behaviour of the pelagic, crawling, and settling stages of Watersipora cucullata (Busk) are described. The main settling period in Sydney Harbour appears to be February-April. The usual negatively phototropic reaction at settling in subdued light could be reversed by increasing the illumination. There was some evidence of gregariousness. When "non-filmed" settling surfaces were offered settling was delayed and a high mortality appeared. In copper solutions of 2.5-5.0 mg Cu/l. larvae settled considerably faster than the controls but metamorphosis was abnormal and lethal. No such acceleration of the settling rate was observed in mercury solutions of the same strength but these appeared to be relatively more lethal.

A simple settling model for batch activated sludge process

2000 ◽  
Vol 42 (3-4) ◽  
pp. 9-16 ◽  
Author(s):  
A.A. Kazmi ◽  
H. Furumai
Keyword(s):  
Activated Sludge ◽  
Mass Balance ◽  
Concentration Profile ◽  
Full Scale ◽  
Initial Mass ◽  
Sediment Surface ◽  
Settling Rate ◽  
Activated Sludge Process ◽  
Time Step ◽  
Critical Concentrations

A simple settling model for the batch activated sludge process was proposed that could predict sludge concentration profile as a function of time. The predicted dynamic biomass profile would be used to quantify biological reactions during settling. The model can be applied by giving easily measurable parameters such as initial MLSS concentration, sludge interface variation which characterizes the settling rate, and SVI as an index of biomass settleability. The model describes the sedimentation process of the sludge by linking three concentrations, namely the MLSS on sludge interface (XH), constant MLSS on sediment surface (XC), and the variable MLSS at the bottom (XB). It was tested for wide ranges of activated sludge concentrations (1750 mg/L-4630 mg/L) and SVI (104-265). The model was applied to express MLSS profile for a full scale SBR as well as for 1 and 2 m column settling tests. The simulated MLSS profile by linking three critical concentrations agrees well with the observed data. Mass balance applied at each time step indicated that the deviation was from −2 to +12% of the total initial mass. The stratified MLSS profile simulated from the model was applied to predict denitrification rate during settling.

scholarly journals Chemometric Optimisation of a Copper Sulphide Tailings Flocculation Process in the Presence of Clays

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 582 ◽  
Author(s):  
Claudia Castillo ◽  
Christian F. Ihle ◽  
Ricardo I. Jeldres
Keyword(s):  
Settling Rate ◽  
Mixing Conditions ◽  
Fine Content ◽  
Operational Conditions ◽  
Coarse Aggregates ◽  
Series Of Experiments ◽  
Sulphide Tailings ◽  
Solids Content ◽  
Two Stages ◽  
Flocculation Process

The presence of fine and ultra-fine gangue minerals in flotation plants can contribute to sub-optimal valuable ore recovery and incomplete water recycling from thickeners, with the performance of the latter equipment relying on adequate flocculation. In order to study the dependence of the flocculation process on the suspension-flocculant mixing conditions, a series of experiments—chosen using chemometric analysis—were carried out by varying mixing conditions, solid concentration, water salinity and flocculant dosage. To this purpose, two different tailings (both featuring coarse and fine content) were considered and a response surface methodology based on a Doehlert experimental design was used. The results suggest that the operational conditions to optimise the flocculated tailings settling rate and the suspended solids that report to a thickener overflow are not necessarily the same. This is a reasonable outcome, given that the settling rate depends on the coarse aggregates generated in the slurry, while the overflow solids content is governed both by either fine particle content (and its characteristics) or small aggregates. It is inferred that to maximise dewatering performance two stages should be involved—a separate treatment of the thickener overflow to remove fine content and thickening at optimal flocculant dosage to enhance this process.

scholarly journals Flocculation performance of anionic starch in oil sand tailings

2018 ◽  
Vol 78 (6) ◽  
pp. 1268-1275
Author(s):  
Nana Zhao ◽  
Hani Al Bitar ◽  
Yunyin Zhu ◽  
Yuming Xu ◽  
Zhiqing Shi
Keyword(s):  
Specific Resistance ◽  
Kaolin Clay ◽  
Settling Rate ◽  
Oil Sand ◽  
Natural Polymers ◽  
Capillary Suction ◽  
Fine Tailings ◽  
Solids Content ◽  
Clay Suspensions

Abstract A series of carboxymethyl starches (CMSs), with various degrees of substitution from 0.1 to 0.79, were synthesized and selected as a model to study the feasibility of using natural polymers as flocculants for oil sand tailings treatment. The flocculation performance of modified CMS in kaolin clay suspensions and oil sand tailings was evaluated in terms of settling rate, solids content, capillary suction time, and specific resistance to filtration of the sediment phase. It was found that the synthesized CMS effectively accelerates settling of kaolin suspensions and oil sand fine tailings, thus demonstrating the feasibility of this application.

Erythrocyte Sedimentation Rates in Inclined Vessels

1973 ◽  
Vol 51 (9) ◽  
pp. 685-690 ◽  
Author(s):  
R. N. O'Brien ◽  
M. B. Hocking ◽  
P. McOrmond ◽  
K. R. Thornton
Keyword(s):  
Cross Section ◽  
Sedimentation Rates ◽  
Settling Rate ◽  
Cross Sectional ◽  
Erythrocyte Sedimentation ◽  
The Cross ◽  
Sectional Shape ◽  
Erythrocyte Sedimentation Rates ◽  
Test Rack ◽  
Settling Rates

The rates of erythrocyte settling have been investigated in round and square cross-section tubes, vertically; and at nine different angles; and with the square tubes flat and on edge, to a minimum of 15° from the horizontal. Apparent settling rates increased as the angle from the horizontal decreased. Real settling rates (vertical settling rates) increased sharply on decreasing the angle from the horizontal, to a maximum at about 60°, and then decreased less abruptly for the shallower angles. The cross-sectional shape of the tube did not significantly affect the settling rates of erythrocytes. Settling in inclined tubes proceeds fast enough to permit clinical erythrocyte settling rate (E.S.R.) tests to be carried out in 10 min in place of the usual 60 min. If the standard E.S.R. test rack deviates as little as 5° from the vertical it can cause the observed settling rates to double relative to readings obtained on a vertical rack.

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