Journal articles on the topic 'Particles Separation'
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1
Duan, Chenlong, Cheng Sheng, Lingling Wu, Yuemin Zhao, Jinfeng He, and Enhui Zhou. "Separation and Recovery of Fine Particles from Waste Circuit Boards Using an Inflatable Tapered Diameter Separation Bed." Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/843579.
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Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (−0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed’s fluid flow field. For 0.5–0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25–0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (−0.125 mm), metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution.
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Cieśla, Antoni, Wojciech Kraszewski, Mikołaj Skowron, Agnieszka Surowiak, and Przemysław Syrek. "Application of electrodynamic drum separator to electronic wastes separation." Gospodarka Surowcami Mineralnymi 32, no. 1 (March 1, 2016): 155–74. http://dx.doi.org/10.1515/gospo-2016-0007.
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AbstractStatic electric fields are used, among others, in technological processes such as electric separation. Electrodynamic separation is a process of separating two or more solid phases of various physical properties by electric field forces. The advantage of electrodynamic separation is possibility of obtaining separation of individual components in dry conditions. This eliminates many operations such as thickening, dewatering, hydrotransportation, additional drying which cause higher energy consumption and higher separation process costs. Efficiency of beneficiation depends on many factors such as: electric properties of feed components, feed particle size distribution, drum rotary speed, electric field intensity in working space of separator, configuration of electrodes or surrounding conditions.The paper presents the working of high-voltage drum separator. The analysis of electric field distribution in separator working space was done. Additionally, distribution of forces acting on particles of dielectric and conductive properties was examined, trajectories of charged particles movement were presented too. The laboratory investigations of electronic wastes were performed in two particle fractions: 0.25–0.5 mm and 0–0.25 mm. It was observed that as a result of selective charging of particles they separate according to surface ability to electrifying what allows to obtain selective separation of components being so-called electronic wastes. The application of electrodynamic drum separator allows to separate such elements as Ti, Cu, Fe, Pb, Sn from plastics occurring in electronic wastes.
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Li, Xiaohong, Junping Duan, Zeng Qu, Jiayun Wang, Miaomiao Ji, and Binzhen Zhang. "Continuous Particle Separation Driven by 3D Ag-PDMS Electrodes with Dielectric Electrophoretic Force Coupled with Inertia Force." Micromachines 13, no. 1 (January 12, 2022): 117. http://dx.doi.org/10.3390/mi13010117.
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Cell separation has become @important in biological and medical applications. Dielectrophoresis (DEP) is widely used due to the advantages it offers, such as the lack of a requirement for biological markers and the fact that it involves no damage to cells or particles. This study aimed to report a novel approach combining 3D sidewall electrodes and contraction/expansion (CEA) structures to separate three kinds of particles with different sizes or dielectric properties continuously. The separation was achieved through the interaction between electrophoretic forces and inertia forces. The CEA channel was capable of sorting particles with different sizes due to inertial forces, and also enhanced the nonuniformity of the electric field. The 3D electrodes generated a non-uniform electric field at the same height as the channels, which increased the action range of the DEP force. Finite element simulations using the commercial software, COMSOL Multiphysics 5.4, were performed to determine the flow field distributions, electric field distributions, and particle trajectories. The separation experiments were assessed by separating 4 µm polystyrene (PS) particles from 20 µm PS particles at different flow rates by experiencing positive and negative DEP. Subsequently, the sorting performances of the 4 µm PS particles, 20 µm PS particles, and 4 µm silica particles with different solution conductivities were observed. Both the numerical simulations and the practical particle separation displayed high separating efficiency (separation of 4 µm PS particles, 94.2%; separation of 20 µm PS particles, 92.1%; separation of 4 µm Silica particles, 95.3%). The proposed approach is expected to open a new approach to cell sorting and separating.
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Tang, Zhaojia, Liming Yu, Fenghua Wang, Na Li, Liuhong Chang, and Ningbo Cui. "Effect of Particle Size and Shape on Separation in a Hydrocyclone." Water 11, no. 1 (December 21, 2018): 16. http://dx.doi.org/10.3390/w11010016.
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Given the complex separation mechanisms of the particulate mixture in a hydrocyclone and the uncertain effects of particle size and shape on separation, this study explored the influence of the maximum projected area of particles on the separation effect as well as single and mixed separations based on CFD–DEM (Computational Fluid Dynamics and Discrete Element Method) coupling and experimental test methods. The results showed that spherical particles flowed out more easily from the downstream as their sizes increased. Furthermore, with the enlargement of maximum projected area, the running space of the particles with the same volume got closer to the upward flow and particles tended to be separated from the upstream. The axial velocity of the combined separation of 60 µm particles and 120 µm particles increased by 25.74% compared with that of single separation of 60 µm particles near the transition section from a cylinder to a cone. The concentration of 60 µm particles near the running space of 120 µm particles increased by 20.73% and those separated from the downstream increased by 4.1%. This study showed the influence of particle size and maximum projected area on the separation effect and the separation mechanism of mixed sand particles in a hydrocyclone, thereby providing a theoretical basis for later studies on the effect of particle size and shape on sedimentation under the cyclone action in a hydrocyclone.
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Li, Xiaohong, Junping Duan, Jiayun Wang, Zeng Qu, Miaomiao Ji, and BinZhen Zhang. "Continuous particle separation of microfluidic chip with integrated inertial separation and dielectrophoresis separation." AIP Advances 12, no. 3 (March 1, 2022): 035148. http://dx.doi.org/10.1063/5.0075823.
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Particle separation is essential in many microfluidic systems such as biomedical analysis and chemical reactions. This study aims to report a microfluidic separation device combining dielectrophoresis force and inertial force to separate particles continuously. Most particles were separated by inertial force via passing through the contraction and expansion channel and then deviated into different outlets via interdigital electrodes. Numerical simulations using the software COMSOL Multiphysics 5.4 were performed to investigate the effects of flow rate and electric field distribution on particles. The separation efficiency was assessed by separating 4 µm polystyrene spheres (PS) from 20 µm PS microspheres at various flow rates. The experimental results showed that the separation efficiency was more than 95%. This microfluidic chip is expected to be applied to cell sorting and biomedicine.
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Tan, Jia Hao, Douglas Kum Tien Tong, and Edwin Chin Yau Chung. "Design and Analysis of a Separator for Aluminium Dust Particle Collection." MATEC Web of Conferences 335 (2021): 03013. http://dx.doi.org/10.1051/matecconf/202133503013.
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Cyclone separators are considered one of the most common and widely used method of separating solid particles from fluids. The focus of this paper was to design a separator that could effectively improve the air quality of an industrial working environment by considering factors such as the nature of the particles and the restrictions on the device such as size and operating condition. To do so, a sample of the dust sample was studied to determine the characteristics of the aluminum dust. An initial separator model which satisfied the separation condition was developed, and a second model was developed with the goal of optimizing and reducing the overall size of the separator. All models developed were subjected to CFD simulations to analyze the flow patterns, separation rate at various particle diameters as well as comparing against the theoretical predicted values. The simulation results showed how the change in various parameters improved the separation efficiency. The total height of the model was approximately 20% smaller than the initial proposed design to fit into the manufacturer’s workbench while the separation efficiencies improved by an average of 5% to 10% across various particle sizes. The results obtained indicated that the efficiency of the particle collection is dependent on the area of the barrel inlet of the separator and the depth of the vortex finder.
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Yu, Xinzhi, Xuesong Jiang, Haiyang Gu, and Fei Shen. "DEM Study of the Motion Characteristics of Rice Particles in the Indented Cylinder Separator." Sensors 23, no. 1 (December 27, 2022): 285. http://dx.doi.org/10.3390/s23010285.
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The precise separation of rice particles is an important step in rice processing. In this paper, discrete element simulations of the motion of rice particles of different integrity in an indented cylinder separator were carried out using numerical simulation methods. The effects of single factors (cylinder rotation rate, cylinder axial inclination angle, and collection trough inclination angle) on the motion trajectories of particles are investigated and the probability distribution functions of particles are obtained. The statistical method of Kullback-Leibler divergence is used to quantitatively evaluate the differences in the probability distribution functions of the escape angles of particles of different degrees of integrity. The purpose of this paper is to determine the optimum parameters for an indent cylinder separator by understanding the material cylinder separating process from particle scale and to provide a basis for the numerical design of a grain particle cylinder separators.
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Li, Xudong, Yuhua Wang, Dongfang Lu, and Xiayu Zheng. "Influence of Separation Angle on the Dry Pneumatic Magnetic Separation." Minerals 12, no. 10 (September 22, 2022): 1192. http://dx.doi.org/10.3390/min12101192.
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To enhance dry magnetic separation of fine-grained materials, our research team developed the pneumatic drum magnetic separator (PDMS), an airflow-aided magnetic separator. Different positions at the separation surface of PDMS have varied separation angles, so particles at different positions may be subjected to varying composite forces, resulting in a mismatch between airflow velocity and magnetic field intensity. However, because the separation process of PDMS is continuous and the separation of particles at a certain position is instantaneous, the separation performance of PDMS at a specific separation angle cannot be investigated. To evaluate optimal operating features at different separation angles, a laboratory dry pneumatic flat magnetic separator (DPFMS) was manufactured, which also makes the airflow pass through the separation plane in the opposite direction to the magnetic force. The separation performance of PDMS was revealed by separation tests for −0.15 + 0.074 mm artificial mixed ore with 0–0.6 m/s airflow on DPFMS at various separation angles. At separation angles of 70° and 90°, the separation efficiency increases with an increase in airflow velocity from 16.68% and 33.09% to 77.72% and 76.54%, respectively; at separation angles of 110°, the separation efficiency increases initially from 89.53% to 90.69%, then decreases to 88.22% and keeps decreasing. The synergistic relationship between airflow drag, magnetic force and gravity were investigated by analyzing the composite force and the motion trajectory of a single particle. The results show that the proper airflow velocity aids in enhancing the distinctions between magnetite and quartz particles in resultant force and movement. However, throughout a wide range of air velocity, while the airflow can improve magnetite and quartz separation efficiency of at small separation angles, it may diminish the separation efficiency at large separation angles.
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Yamasaki, Haruhiko, Hiroyuki Wakimoto, Takeshi Kamimura, Kazuhiro Hattori, Petter Nekså, and Hiroshi Yamaguchi. "Visualization and Measurement of Swirling Flow of Dry Ice Particles in Cyclone Separator-Sublimator." Energies 15, no. 11 (June 3, 2022): 4128. http://dx.doi.org/10.3390/en15114128.
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The dry ice sublimation process of carbon dioxide (CO2) is a unique, environmentally friendly technology that can achieve a temperature of −56 °C or lower, which is a triple point of CO2 in CO2 refrigeration systems. In this study, a cyclone separator-evaporator was proposed to separate dry ice particles in an evaporator. As an initial step before introducing the cyclone separator-evaporator into an actual refrigeration system, a prototype cyclone separator-evaporator was constructed to visualize dry ice particles in a separation chamber. A high-speed camera was used to visualize the non-uniform flow of dry ice particles that repeatedly coalescence and collision in a swirl section. Consequently, the dry ice particle size and the circumferential and axial velocities of dry ice were measured. The results show that the equivalent diameter of the most abundant dry ice particles in the cyclone separation chamber is 2.0 mm. As the inner diameter of the separation section decreases, dry ice particles coalesce and grow from an equivalent diameter of 4 mm to a maximum of 40 mm. In addition, the comparison of the experimental and simulation results shows that the drag force due to CO2 gas flow is dominant in the circumferential velocity of dry ice particles.
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Landauer, Johann, and Petra Foerst. "Influence of Particle Charge and Size Distribution on Triboelectric Separation—New Evidence Revealed by In Situ Particle Size Measurements." Processes 7, no. 6 (June 19, 2019): 381. http://dx.doi.org/10.3390/pr7060381.
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Triboelectric charging is a potentially suitable tool for separating fine dry powders, but the charging process is not yet completely understood. Although physical descriptions of triboelectric charging have been proposed, these proposals generally assume the standard conditions of particles and surfaces without considering dispersity. To better understand the influence of particle charge on particle size distribution, we determined the in situ particle size in a protein–starch mixture injected into a separation chamber. The particle size distribution of the mixture was determined near the electrodes at different distances from the separation chamber inlet. The particle size decreased along both electrodes, indicating a higher protein than starch content near the electrodes. Moreover, the height distribution of the powder deposition and protein content along the electrodes were determined in further experiments, and the minimum charge of a particle that ensures its separation in a given region of the separation chamber was determined in a computational fluid dynamics simulation. According to the results, the charge on the particles is distributed and apparently independent of particle size.
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Hong, Ji Jian, Ding Yu Xi, and Wang Xue Jiao. "Numerical Simulation of Particle Separation in a Hydrocyclone." Applied Mechanics and Materials 713-715 (January 2015): 1786–89. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.1786.
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The mixture two-phase turbulence model and theory of particle dynamics is used to simulate the high concentration water-sand two-phase flow in a hydrocyclone. The article mainly analyzes the particle volumetric concentration distribution and separative efficiency of different diameter particles in a hydrocyclone. The simulation result shows that the particle volumetric concentration distribution of different diameter particles is nonuniform in a hydrocyclone. In the annular space, the small diameter particles are affected by the shortcut flow greatly and have high concentration near the wall of the overflow pipe, while the big diameter particles are mainly distributed near the wall in a hydrocyclone. In cylinder space and cone space, different-diameter particles show a similar distribution, the smaller-diameter particles mainly in inner vortex and the larger-diameter particles in outer vortex.
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Cârlescu, Petru, Ioan Tenu, Marius Baetu, and Radu Rosca. "CFD Study on must of Grapes Separation in a Hydrocyclone." Advanced Materials Research 837 (November 2013): 645–50. http://dx.doi.org/10.4028/www.scientific.net/amr.837.645.
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Abstract. Hydrocyclones are increasingly used in the food industry for various separation and purification. In this paper, an optimization was made to design a hydrocyclone model using CFD (Computational Fluid Dynamics). CFD simulation is performed with FLUENT software by coupling the Reynolds Stress Model (RSM) for must of grapes flow with Discrete Phase Model (DPM) for solid particles trajectory. Coupling of discrete phase (particles) and continuous phase (must of grapes) in the mathematical model is set so that the continuous phase to influence discrete phase. Tracking particles traiectory in this hydrocyclone allows advanced degree is separation so obtained to the maximum particle size approaching the size of a yeast cell 10 μm, without separating them. Hydrocyclone dimensional designed simulation was performed and analyzed on an experimental pilot plant for three different must flow rates supply. Introduced particle flow rates simulation and experiment does not exceed 10% of the must flow rates. The degree of separation obtained is in agreement with experimental data.
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Bragg, Andrew D. "Analysis of the forward and backward in time pair-separation probability density functions for inertial particles in isotropic turbulence." Journal of Fluid Mechanics 830 (September 29, 2017): 63–92. http://dx.doi.org/10.1017/jfm.2017.586.
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In this paper we investigate, using theory and direct numerical simulations (DNS), the forward in time (FIT) and backward in time (BIT) probability density functions (PDFs) of the separation of inertial particle pairs in isotropic turbulence. In agreement with our earlier study (Bragg et al., Phys. Fluids, vol. 28, 2016, 013305), where we compared the FIT and BIT mean-square separations, we find that inertial particles separate much faster BIT than FIT, with the strength of the irreversibility depending upon the final/initial separation of the particle pair and their Stokes number $St$. However, we also find that the irreversibility shows up in subtle ways in the behaviour of the full PDF that it does not in the mean-square separation. In the theory, we derive new predictions, including a prediction for the BIT/FIT PDF for $St\geqslant O(1)$, and for final/initial separations in the dissipation regime. The prediction shows how caustics in the particle relative velocities in the dissipation range affect the scaling of the pair-separation PDF, leading to a PDF with an algebraically decaying tail. The predicted functional behaviour of the PDFs is universal, in that it does not depend upon the level of intermittency in the underlying turbulence. We also analyse the pair-separation PDFs for fluid particles at short times, and construct theoretical predictions using the multifractal formalism to describe the fluid relative velocity distributions. The theoretical and numerical results both suggest that the extreme events in the inertial particle-pair dispersion at the small scales are dominated by their non-local interaction with the turbulent velocity field, rather than due to the strong dissipation range intermittency of the turbulence itself. In fact, our theoretical results predict that for final/initial separations in the dissipation range, when $St\gtrsim 1$, the tails of the pair-separation PDFs decay faster as the Taylor Reynolds number $Re_{\unicode[STIX]{x1D706}}$ is increased, the opposite of what would be expected for fluid particles.
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Al-Azab, Tariq, Jamil Haddad, and Fadi Alfaqs. "Investigation of the effect of several parameters on the applicability of magnetic separation method." Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, no. 4 (2021): 69–73. http://dx.doi.org/10.33271/nvngu/2021-4/069.
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Purpose. This research investigates the separation process performed by a magnetic separator. The magnetic separation process is used to isolate ferrous materials from those which are not. Hence, a prototype of a dry magnetic separator is designed. It should be said that this study defines the effect of different parameters (roll speed, magnetic force, and mass of silica sand particle) on separation efficiency. Methodology. The influence of several parameters of the magnetic separator such as magnetic force, centrifugal force, and properties of particle (mass, shape, etc.) were studied theoretically and simulated by SolidWorks software. The optimum conditions of the magnetic separator were obtained, and several trials were performed to find the point that results in a lower effect of roller speed and a higher effect of the magnetic force on the particle in order to achieve higher separating efficiency. Findings. The results show that the centrifugal force are the most important variable influencing separating efficiency. Moreover, it was found that blade angle magnitude of (174) degree with magnetic force between (1.71E-05 to 6.3E-05 N) and roll speed from (84 to 105 rpm) are the optimum separating conditions to reach higher rate of the separating process. Originality. This is the first time that the effect of the gap distance between the magnet and the feeding particles on the magnetic force has been studied. Furthermore, the effect of centrifugal force on magnetic separator force is investigated theoretically and numerically in order to be compared for different parameters. Practical value. The new prototype design of the magnetic separating unit is promising and efficient since the parameters can be varied based on the type and characteristics of materials. It is also revealed that separating time of the materials is reduced. Hence, this type of construction of a magnetic separator is recommended for industrial applications.
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Wang, Purong, and Guoyin Xu. "Development and Application Characteristics of High Gradient Magnetic Separator." Journal of Physics: Conference Series 2160, no. 1 (January 1, 2022): 012057. http://dx.doi.org/10.1088/1742-6596/2160/1/012057.
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Abstract As one of the most effective techniques for fine particle processing, high gradient magnetic separation is mainly used in the separation and enrichment of fine and weak magnetic particles and other important industrial fields. High gradient magnetic separator is a new type of high intensity magnetic separator, which has strong ability to capture fine and weak magnetic particles, developed on the basis of ordinary high intensity magnetic separator. Based on the early periodic- high -gradient magnetic separators, the optimization development direction of high gradient magnetic separators and their application characteristics of various high gradient magnetic separators in these decades were summarized, and the future development directions of high gradient magnetic separator were presented.
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Jang, Min-Ho, Yong-Ho Choi, Heung-Joe Jung, Yong-Hoon Jeong, and Dong-Heui Kwak. "Feasibility Evaluation on Single-Collector Collision Model to Separate Microplastics in Micro Bubble Flotation Process." Journal of Korean Society of Environmental Engineers 43, no. 1 (January 31, 2021): 10–19. http://dx.doi.org/10.4491/ksee.2021.43.1.10.
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Objectives:The single collector collision (SCC) model is a model that predicts the separation efficiency of particles based on the collision efficiency between microbubbles and particles in the particle separation process. In order to remove micro-plastics (MPs) particles, which have recently been known to be harmful, we tried to analyze the impact and separation efficiency of MPs based on the SCC model and evaluate its application feasibility.Methods:Based on the SCC model, the collision efficiency prediction for MPs particle removal was simulated and the separation efficiency was evaluated. In addition, a series of flotation experiments were conducted using a flotation device that injects microbubbles to remove MPs particles suspended in water, and the experimental results and predicted values were compared.Results and Discussion:Using the SCC model, the collision efficiency according to the size distribution of MPs particles was not significantly different from that of typical particles (clay, kaolin) in water. Based on this collision efficiency, the maximum removal efficiency of MPs particles separated from the water body is predicted to reach about 90%. On the other hand, the initial collision-adhesion coefficient () of the MPs particles based on the SCC model was 0.03 to 0.1, showing a slight difference from the clay particles having the range of 0.3 to 0.4. The flotation separation efficiency of the MPs particles evaluated and predicted by applying this initial collision-adhesion coefficient showed a range similar to the measured value. In addition, the particle separation efficiency according to the increase of the measured bubble volume concentration to improve the particle separation efficiency also showed a pattern similar to the predicted value.Conclusions:In the flotation process, the initial collision-adhesion efficiency of the MPs particles predicted by the SCC model was lower than that of the kaolin particles. Based on the simple and simple model SCC theory, it was confirmed that it can be applied to the flotation separation analysis of MPs particles.
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Kim, Moonjeong, Jemyung Cha, and Jeung Sang Go. "Ring-Shaped Baffle Effect on Separation Performance of Lithium Carbonate Micro Particles in a Centrifugal Classifier." Micromachines 11, no. 11 (October 30, 2020): 980. http://dx.doi.org/10.3390/mi11110980.
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In this work, a centrifugal classifier for separating lithium carbonate particles, used as a cathode material for lithium-ion batteries, was investigated. This work numerically evaluates the internal flow and particle separation performance of the centrifugal classifier. The complex turbulent flow field in the classifier is key to understanding particle motion. A Reynolds stress model, to describe air flow field, and a discrete phase model, to track particle motion, were applied to a numerical simulation. Design parameters such as mass flow rate and rotor speed were investigated, and a ring-shaped baffle, in particular, was designed to investigate the effects of flow and particle separation in the centrifugal classifier. The simple geometry of the baffle changes the movement direction of unseparated particles to the rotor cage region, and increases the local air velocity in the separation zone. The numerical analysis results were verified through a baffle experiment.
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Potapov, Valentin, Anatoliy Afanasyev, Vladimir Potapov, Sergei Frolov, and Ekaterina Franyuk. "Math modeling of particle movements in a friction separator." E3S Web of Conferences 177 (2020): 03001. http://dx.doi.org/10.1051/e3sconf/202017703001.
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A mathematical model of particles movement of separated material in a friction separator is proposed. It includes equations of their movement at each stage of separation (along a rough inclined plane, on a curvilinear part of a springboard, impact of a particle on the surface of a drum, free motion before leaving the separation zone), and differential equations of particle movement in circulating air flow created by a rotating drum; Each of these phases of motion is described by a system of equations obtained on the basis of basic laws of mechanics. An analysis of a particle motion along aslope plane was carried out on the basis of the law on energy changes. Depending on the ratios of the recovery factor and instantaneous friction, being random variables and also the coordinates of a point impact the particle is possible to move along different trajectories with different initial conditions. The mathematical model of the process of separation of loose multicomponent materials on a friction drum-shelf separator makes it possible to investigate comprehensively the process of separation of particles on friction and elastic properties and to optimize the operating modes of the apparatus at relatively low costs without using macaques and prototypes and investigate them experimentally. On the basis of analysis of the proposed theories of particles motion, the main ways are formulated of further improvement of methodology for designing and creating friction devices.
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Gangadhar, Anirudh, and Siva A. Vanapalli. "Inertial focusing of particles and cells in the microfluidic labyrinth device: Role of sharp turns." Biomicrofluidics 16, no. 4 (July 2022): 044114. http://dx.doi.org/10.1063/5.0101582.
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Inertial, size-based focusing was investigated in the microfluidic labyrinth device consisting of several U-shaped turns along with circular loops. Turns are associated with tight curvature and, therefore, induce strong Dean forces for separating particles; however, systematic studies exploring this possibility do not exist. We characterized the focusing dynamics of different-sized rigid particles, cancer cells, and white blood cells over a range of fluid Reynolds numbers [Formula: see text]. Streak widths of the focused particle streams at all the turns showed intermittent fluctuations that were substantial for smaller particles and at higher [Formula: see text]. In contrast, cell streaks were less prone to fluctuations. Computational fluid dynamics simulations revealed the existence of strong turn-induced Dean vortices, which help explain the intermittent fluctuations seen in particle focusing. Next, we developed a measure of pairwise separability to evaluate the quality of separation between focused streams of two different particle sizes. Using this, we assessed the impact of a single sharp turn on separation. In general, the separability was found to vary significantly as particles traversed the tight-curvature U-turn. Comparing the separability at the entry and exit sections, we found that turns either improved or reduced separation between different-sized particles depending on [Formula: see text]. Finally, we evaluated the separability at the downstream expansion section to quantify the performance of the labyrinth device in terms of achieving size-based enrichment of particles and cells. Overall, our results show that turns are better for cell focusing and separation given that they are more immune to curvature-driven fluctuations in comparison to rigid particles.
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Deeva, V. S., S. М. Slobodyan, and V. S. Teterin. "Optimization of Oil Particles Separation Disperser Parameters." Materials Science Forum 870 (September 2016): 677–82. http://dx.doi.org/10.4028/www.scientific.net/msf.870.677.
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Retaining structure of homogeneous fluid and granular stream is one of the main criteria for technological process assuring the high quality outcome in many industries, including mechanical engineering and oil & gas industry. For example, in oil and gas industry during the pipeline transportation of oils there is a strong trend for cluster aggregation, and particle coarsening and entanglement. Dehomogenization of particle stream results in reverse dynamics of the stream. The importance of prevention and minimization of small particles coalescence by separating the oil stream leads to the need of improving the properties of the dispersers to boost their efficiency. Our paper investigates the operating principle of the disperser for separating particles (separator), which is designed by the authors. We have considered a particle stream of dispersed structure. We have obtained the conformity with the stability of the disperser operation. To yield the results we use the extremum problems for differential equations. This approach provides strong evidence that there are optimum parameters of the dispersers, which result in better stability of the particle stream.
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Wassberg, Therese R., Mathilde L. Witt, Murat Serhatlioglu, Christian F. Nielsen, Ian D. Hickson, and Anders Kristensen. "Size-based chromosome separation in a microfluidic particle separation device using viscoelastic fluids." EPJ Web of Conferences 266 (2022): 12007. http://dx.doi.org/10.1051/epjconf/202226612007.
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Viscoelastic flow-based particle manipulation techniques enable bio-particle focusing, separation, and enrichment by precisely tuning the rheological parameters, flow conditions, and microchannel geometry. In this study, we fabricated a PDMS-based single inlet/outlet microchannel to separate bio-particles by their size ranging from 1-10 μm. Flow conditions and rheological properties are optimized using 2 μm and 4 μm Polystyrene beads to reach the best particle separation condition. We demonstrated the size-based separation of human chromosomes by separating 1-2 μm size small chromosomes from 8-10 μm size large chromosomes. Thanks to its miniaturized size and simplicity, the isolation chip and unique viscoelastic separation method have great potential to be used as a future pioneering tool for genetic applications to study chromosome abnormalities such as fragile-X and trisomy.
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Zhang, Yuekan, Meng Yang, Lanyue Jiang, Hui Wang, Jinguang Xu, and Junru Yang. "High Concentration Fine Particle Separation Performance in Hydrocyclones." Minerals 11, no. 3 (March 16, 2021): 307. http://dx.doi.org/10.3390/min11030307.
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The vast majority of current research on hydrocyclone field centrifugal separation focuses on low concentration fluids having volume fraction less than 3%. For high-concentration fluids having volume fractions greater than 10%, which are often encountered in engineering, the law governing particle motion and the classification mechanism are still unclear. In order to gain insights into the interaction between fine particles in the high concentration hydrocyclone field and to improve the hydrocyclone separation performance of these particles, a Dense Discrete Phase Model (DDPM) of the Euler-Eulerian method under the Ansys Fluent 14.5 software was employed. Numerical simulations were carried out to study the characteristics of the hydrocyclone field of dense particles and the influence of parameters, such as the diameter of the overflow outlet, diameter of the underflow outlet, and material concentration, on separation performance. The trajectories and separation efficiencies of two kinds of fine particles with different densities and six different particle sizes at high concentration were obtained. The results show that for the hydrocyclone classification of high-concentration fine particles, particles with large density and small particle size are more likely to enter the internal cyclone and discharge from the overflow. Particles with small density and large particle size are more likely to enter the external cyclone and discharge from the underflow. The research results of this topic could provide a feasible reference and theoretical basis for the centrifugal separation of high-concentration fine particle fluid.
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Andreu, Jordi S., Pablo Barbero, Juan Camacho, and Jordi Faraudo. "Simulation of Magnetophoretic Separation Processes in Dispersions of Superparamagnetic Nanoparticles in the Noncooperative Regime." Journal of Nanomaterials 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/678581.
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Magnetic separation has gained much attention due to its implications in different fields, becoming feasible as an alternative to existent technologies at the industrial and lab scale. Substantial efforts are focused to improve the magnetic particles used in these applications. Here we show how a relatively simple and low-cost simulation strategy (tracer simulations) can be employed to predict the effect of various key factors in magnetic separation processes, namely, particle properties and magnetic separator designs. For concreteness, we consider here specific problems in magnetic separation. The first one is the effect of different profiles of the magnetic field in the separation of magnetic nanoparticles, and the second one is the magnetophoresis of colloidal particles in a dispersion of magnetic nanoparticles.
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Yu, Chi, Runhui Geng, and Xinwen Wang. "A Numerical Study of Separation Performance of Vibrating Flip-Flow Screens for Cohesive Particles." Minerals 11, no. 6 (June 14, 2021): 631. http://dx.doi.org/10.3390/min11060631.
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Vibrating flip-flow screens (VFFS) are widely used to separate high-viscosity and fine materials. The most remarkable characteristic is that the vibration intensity of the screen frame is only 2–3 g (g represents the gravitational acceleration), while the vibration intensity of the screen surface can reach 30–50 g. This effectively solves the problem of the blocking screen aperture in the screening process of moist particles. In this paper, the approximate state of motion of the sieve mat is realized by setting the discrete rigid motion at multiple points on the elastic sieve mat of the VFFS. The effects of surface energy levels between particles separated via screening performance were compared and analyzed. The results show that the flow characteristics of particles have a great influence on the separation performance. For 8 mm particle screening, the particle’s velocity dominates its movement and screening behavior in the range of 0–8 J/m2 surface energy. In the feeding end region (Sections 1 and 2), with the increase in the surface energy, the particle’s velocity decreases, and the contact time between the particles and the screen surface increases, and so the passage increases. When the surface energy level continues to increase, the particles agglomerate together due to the effect of the cohesive force, and the effect of the particle’s agglomeration is greater than the particle velocity. Due to the agglomeration of particles, the difficulty of particles passing through the screen increases, and the yields of various size fractions in the feeding end decrease to some extent. In the transporting process, the agglomerated particles need to travel a certain distance before depolymerization, and the stronger the adhesive force between particles, the larger the depolymerization distance. Therefore, for the case of higher surface energy, the screening percentage near the discharging end (Sections 3 and 4) is greater. The above research is helpful to better understand and optimize the screening process of VFFS.
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Hashim, Aimi Noorliyana, Kasmuin Mohd Zaheruddin, and Hussin Kamarudin. "A Study of Liberation and Separation Process of Metals from Printed Circuit Boards (PCBs) Scraps." Key Engineering Materials 594-595 (December 2013): 123–27. http://dx.doi.org/10.4028/www.scientific.net/kem.594-595.123.
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Since the metallic elements are covered with or encapsulated by various plastic or ceramic materials on printed circuit boards (PCBs), a pre-treatment process allowing their liberation and separation is first needed in order to facilitate proficient extraction. In this work, a fundamental study has been carried out to recover metallic concentrates from PCBs scraps. The most important step is to separate or release particles from the associated gangue minerals at the possible liberation particle size. The samples of printed circuit boards were separated into the magnetic and non-magnetic fractions by Rare-earth Roll Magnetic Separator. Then, the magnetic and non-magnetic fractions were separated to heavy fraction (metallic elements) and light fraction (plastic) by Mozley Laboratory Table Separator. Results show that the unliberated particles still remain in the comminution fines PCBs. The use of Rare-earth roll magnetic separation was clarified that the Fe, Ni and Zn element tend to be condensed in magnetic particles. Meanwhile Cu element tends to be release in non-magnetic particles. Mozley Laboratory Table Separation was capable to obtain fractions with relatively high concentrations of metallic elements. This study is expected to provide useful data for the efficient physical separation of metallic components from printed circuit boards scraps.
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Li, Xudong, Yuhua Wang, Dongfang Lu, Xiayu Zheng, and Xuesong Gao. "Optimization of Airflow Field for Pneumatic Drum Magnetic Separator to Improve the Separation Efficiency." Minerals 11, no. 11 (November 5, 2021): 1228. http://dx.doi.org/10.3390/min11111228.
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Traditional dry magnetic separation has poor separation efficiency for fine-grained materials, and combining airflow and a magnetic field may be one of the most effective means to improve it. Based on the pneumatic drum magnetic separator developed by our team, an improved pneumatic magnetic separator with a segmented flow field is proposed, which pushes materials to move along the separation surface. Analysis of flow field in the separation zone and the forces on particles show that the improved pneumatic magnetic separator makes it easier to collect fine magnetic particles, while nonmagnetic particles are more easily removed by airflow. Separation test results also show that the iron grade and the recovery of concentrate improved from 37.89% and 74.75% to 51.76% and 91.79%, respectively. The separation efficiency of the pneumatic drum magnetic separator has been remarkably improved by optimizing airflow field in the separation zone.
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Liu, Jianjun, Zixing Xue, Zhenhai Dong, Xiaofeng Yang, Yafeng Fu, Xiaofei Man, and Dongfang Lu. "Multiphysics Modeling Simulation and Optimization of Aerodynamic Drum Magnetic Separator." Minerals 11, no. 7 (June 25, 2021): 680. http://dx.doi.org/10.3390/min11070680.
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Aerodynamic Drum Magnetic Separator (ADMS) uses an adjustable air flow to enhance the separation of magnetic particles from gangue. In order to explore the matching relationship between the magnetic field, the flow field, and the gravity field, as well as the capture and separation behavior of particles under the action of multi-physics, a related simulation model is established using the finite element software COMSOL Multiphysics and the accuracy of the simulation results is verified by measurement, formula calculation, and magnetic separation experiment. The trajectories and capture probabilities of particles in different magnetic fields and flow fields are calculated, as well as the critical airflow velocity corresponding to a specific capture probability. In addition, the magnetic field characteristics and particle capture effect of N-S alternate arrangement and N-N homopolar arrangement are compared by optimizing the permutation of magnetic poles. This model may provide a reference for the accurate control of magnetic separation enhanced by a coupling force field.
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Ni, Chen, and Di Jiang. "Three-Dimensional Numerical Simulation of Particle Focusing and Separation in Viscoelastic Fluids." Micromachines 11, no. 10 (September 30, 2020): 908. http://dx.doi.org/10.3390/mi11100908.
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Particle focusing and separation using viscoelastic microfluidic technology have attracted lots of attention in many applications. In this paper, a three-dimensional lattice Boltzmann method (LBM) coupled with the immersed boundary method (IBM) is employed to study the focusing and separation of particles in viscoelastic fluid. In this method, the viscoelastic fluid is simulated by the LBM with two sets of distribution functions and the fluid–particle interaction is calculated by the IBM. The performance of particle focusing under different microchannel aspect ratios (AR) is explored and the focusing equilibrium positions of the particles with various elasticity numbers and particle diameters are compared to illustrate the mechanism of particle focusing and separation in viscoelastic fluids. The results indicate that, for particle focusing in the square channel (AR = 1), the centerline single focusing becomes a bistable focusing at the centerline and corners as El increases. In the rectangular channels (AR < 1), particles with different diameters have different equilibrium positions. The equilibrium position of large particles is closer to the wall, and large particles have a faster lateral migration speed and few large particles migrate towards the channel center. Compared with the square channel, the rectangular channel is a better design for particle separation.
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Dezhkam, Rasool, Hoseyn A. Amiri, David J. Collins, and Morteza Miansari. "Continuous Submicron Particle Separation via Vortex-Enhanced Ionic Concentration Polarization: A Numerical Investigation." Micromachines 13, no. 12 (December 12, 2022): 2203. http://dx.doi.org/10.3390/mi13122203.
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Separation and isolation of suspended submicron particles is fundamental to a wide range of applications, including desalination, chemical processing, and medical diagnostics. Ion concentration polarization (ICP), an electrokinetic phenomenon in micro-nano interfaces, has gained attention due to its unique ability to manipulate molecules or particles in suspension and solution. Less well understood, though, is the ability of this phenomenon to generate circulatory fluid flow, and how this enables and enhances continuous particle capture. Here, we perform a comprehensive study of a low-voltage ICP, demonstrating a new electrokinetic method for extracting submicron particles via flow-enhanced particle redirection. To do so, a 2D-FEM model solves the Poisson–Nernst–Planck equation coupled with the Navier–Stokes and continuity equations. Four distinct operational modes (Allowed, Blocked, Captured, and Dodged) were recognized as a function of the particle’s charges and sizes, resulting in the capture or release from ICP-induced vortices, with the critical particle dimensions determined by appropriately tuning inlet flow rates (200–800 [µm/s]) and applied voltages (0–2.5 [V]). It is found that vortices are generated above a non-dimensional ICP-induced velocity of , which represents an equilibrium between ICP velocity and lateral flow velocity. It was also found that in the case of multi-target separation, the surface charge of the particle, rather than a particle’s size, is the primary determinant of particle trajectory. These findings contribute to a better understanding of ICP-based particle separation and isolation, as well as laying the foundations for the rational design and optimization of ICP-based sorting systems.
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Ljunggren, M., and L. Jönsson. "Separation characteristics in dissolved air flotation - pilot and full-scale demonstration." Water Science and Technology 48, no. 3 (August 1, 2003): 89–96. http://dx.doi.org/10.2166/wst.2003.0169.
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This study presents practical implications for particle separation in Dissolved Air Flotation (DAF). The objectives were to localise where particles are separated from the water phase and to determine what particles, in terms of size, are removed by the DAF-process. Both pilot- and full-scale plants were investigated. Particle sizes were analysed with a light-blocking particle counter and an optical borescope was used for visualisation of particle-bubble aggregates. It was found that particles are preferably separated upstream in the process, i.e. close to the contact zone. Furthermore, separation efficiency for particles increased with increasing particle size.
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BEC, J., L. BIFERALE, A. S. LANOTTE, A. SCAGLIARINI, and F. TOSCHI. "Turbulent pair dispersion of inertial particles." Journal of Fluid Mechanics 645 (February 9, 2010): 497–528. http://dx.doi.org/10.1017/s0022112009992783.
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The relative dispersion of pairs of inertial point particles in incompressible, homogeneous and isotropic three-dimensional turbulence is studied by means of direct numerical simulations at two values of the Taylor-scale Reynolds number Reλ ~ 200 and Reλ ~ 400, corresponding to resolutions of 5123 and 20483 grid points, respectively. The evolution of both heavy and light particle pairs is analysed by varying the particle Stokes number and the fluid-to-particle density ratio. For particles much heavier than the fluid, the range of available Stokes numbers is St ∈ [0.1 : 70], while for light particles the Stokes numbers span the range St ∈ [0.1 : 3] and the density ratio is varied up to the limit of vanishing particle density. For heavy particles, it is found that turbulent dispersion is schematically governed by two temporal regimes. The first is dominated by the presence, at large Stokes numbers, of small-scale caustics in the particle velocity statistics, and it lasts until heavy particle velocities have relaxed towards the underlying flow velocities. At such large scales, a second regime starts where heavy particles separate as tracers' particles would do. As a consequence, at increasing inertia, a larger transient stage is observed, and the Richardson diffusion of simple tracers is recovered only at large times and large scales. These features also arise from a statistical closure of the equation of motion for heavy particle separation that is proposed and is supported by the numerical results. In the case of light particles with high density ratio, strong small-scale clustering leads to a considerable fraction of pairs that do not separate at all, although the mean separation increases with time. This effect strongly alters the shape of the probability density function of light particle separations.
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Yanai, Takuma, Takatomo Ouchi, Masumi Yamada, and Minoru Seki. "Hydrodynamic Microparticle Separation Mechanism Using Three-Dimensional Flow Profiles in Dual-Depth and Asymmetric Lattice-Shaped Microchannel Networks." Micromachines 10, no. 6 (June 25, 2019): 425. http://dx.doi.org/10.3390/mi10060425.
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We herein propose a new hydrodynamic mechanism of particle separation using dual-depth, lattice-patterned asymmetric microchannel networks. This mechanism utilizes three-dimensional (3D) laminar flow profiles formed at intersections of lattice channels. Large particles, primarily flowing near the bottom surface, frequently enter the shallower channels (separation channels), whereas smaller particles flowing near the microchannel ceiling primarily flow along the deeper channels (main channels). Consequently, size-based continuous particle separation was achieved in the lateral direction in the lattice area. We confirmed that the depth of the main channel was a critical factor dominating the particle separation efficiencies, and the combination of 15-μm-deep separation channels and 40-μm-deep main channels demonstrated the good separation ability for 3–10-μm particles. We prepared several types of microchannels and successfully tuned the particle separation size. Furthermore, the input position of the particle suspension was controlled by adjusting the input flow rates and/or using a Y-shaped inlet connector that resulted in a significant improvement in the separation precision. The presented concept is a good example of a new type of microfluidic particle separation mechanism using 3D flows and may potentially be applicable to the sorting of various types of micrometer-sized objects, including living cells and synthetic microparticles.
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Wang, Xin, Yuhong Liu, Jinchi Zhao, Yujing Zhou, and Fei Wang. "Numerical Simulation of an Oil Mist Particle Emission and Gas–Oil Separation Device of a Closed Machine Tool in the Post-Environmental Area." International Journal of Environmental Research and Public Health 19, no. 24 (December 7, 2022): 16415. http://dx.doi.org/10.3390/ijerph192416415.
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Owing to the airflow field within airtight machines, oil mist particles escape with the airflow from the machine shell gaps and are emitted externally to the post-environmental area, causing air pollution and threatening workers’ health. The existing local exhaust system is ineffective in capturing oil mist particles. This study proposes a gas–oil separation device that can “in-situ control” the oil mist particles in situ and weaken their outgoing emission and that uses numerical simulations to compare and analyse the emission characteristics of oil mist particles, before and after the addition of the separation device at different exhaust air volumes and particle emission speeds, and to design the structural parameters of the device to improve the separation efficiency of oil mist particles. The structural parameters of the proposed device are designed to improve the separation efficiency of oil mist particles. Studies have shown that for every 200 m3/h increase in exhaust air volume, the capture efficiency increases by around 3%, and the particle concentration at the gap in the machine loading door decreases from 9.4 × 10−7 kg/m3 to 7.7 × 10−7 kg/m3. The overall escape rate of oil mist particles is in the range of 10–13% after the addition of a pressure relief device. Numerical simulations are performed to analyse the effects of inlet airflow velocity, folding plate spacing, and folding plate angle on the separation efficiency of oil mist particles. Results show that an increase in the inlet velocity of the airflow increases the particle separation efficiency. The most suitable structural parameters for the separation device and the machine are as follows: 60° angle of the folding plate and 30 mm distance between plates, where the separation efficiency is above 80%, and the average separation efficiency is about 86%. The results of this study can be used as a reference for the study of the emission of oil mist particles from enclosed mechanical cutting machines.
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Leistner, Tom, Michael Türk, Alfred Weber, Christian Weber, and Urs A. Peuker. "Selective Separation Using Fluid-Liquid Interfaces." Materials Science Forum 959 (June 2019): 113–24. http://dx.doi.org/10.4028/www.scientific.net/msf.959.113.
Full textAbstract:
Interfaces between two fluid phases are a potential barrier for particles. Certain particles may not be able to pass such an interface, because they have to overcome a certain resistance. The latter depends on the strength of the interface, which is the surface tension. The second relevant property is the three phase wetting angle, which shows the fluid with the preferred wetting to the particle surface. It depends on the particle properties, like chemical composition, surface structure and surface modification. The third relevant parameter is the particle size. From these three main influence parameters it emerges that fluid-fluid interfaces can show a selectivity to special particle properties, which enables a separation of a particle mixture. Since there are possibilities to address the governing effects, the separation cut, size or composition cut respectively, can be engineered in a certain range. Separation at boundaries is feasible when the driving force is in the same order of magnitude as the retaining resistance force of the interface. The driving force is either the Brownian movement for very small particles or any field force like gravity or the centrifugal force. To describe the separation at interfaces it is necessary to understand the process of the phase transfer of particles through the interface, either the gas-liquid or the liquid-liquid interface between two immiscible liquids. In addition to the effects mentioned above, also dynamic phenomena such as surfactant depletion of the interface may have to be taken into account.
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Madyshev, I. N., V. V. Kharkov, V. G. Bolotnov, and A. V. Dmitriev. "Pressure Drop and Particle Collection Efficiency of Multivortex Separator." IOP Conference Series: Earth and Environmental Science 988, no. 4 (February 1, 2022): 042069. http://dx.doi.org/10.1088/1755-1315/988/4/042069.
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Abstract The purification of gas emissions from dispersed particles is presently one of the mandatory measures to protect the air basin for most industrial enterprises. The authors developed a device for gas cleaning with separation elements in the form of a profile with rectangular vertical slots. Such a design creates numerous small vortices, which leads to an increase in collection efficiency. The paper aims to numerically determine the effect of the design and operating conditions on the particle deposition efficiency and the pressure drop of the multivortex separator. The height of the rectangular slots varied from 55 to 94 mm. In addition, the size of the dispersed particles changed from 1 to 15 μm in diameter. The results show that a decrease of resistance coefficient is observed with an increase in the height of the rectangular slot in the separation element. The results indicate that separation elements should be designed with a small height of rectangular slots and located in the lower part to collect fine particles in the multivortex separator efficiently.
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Zhou, Yuanye, Tianlong See, Shan Zhong, Zhu Liu, and Lin Li. "A massive reduction of dust particle adhesion in a cyclone by the introduction of a wedge." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 17 (September 1, 2017): 3102–14. http://dx.doi.org/10.1177/0954406217728978.
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Particle adhesion in a cyclone, such as a cyclonic vacuum cleaner, can significantly reduce its efficiency. An investigation is presented here on the particle adhesion in a cyclone from a vacuum cleaner that consists of a primary separation stage (a cylindrical chamber) and a secondary separation stage (14 cyclones). The flow direction in the primary separation stage was modified by the use of a wedge of 40 mm × 40 mm × 6 mm at the inlet of the primary separation stage, which affected the particle trajectory in the primary separation stage and the particle inlet position in the cyclone while keeping the air flow direction and velocity (without particles being loaded), the Hamaker constant, particle size and the particle charge unaffected. The particle inlet position in the cyclone was varied from the lower portion (without wedge) to the upper portion (with wedge). Without the wedge, a spiral pattern of particle (plaster particles, average size 1.13 μm) adhesion onto the inner wall of the cyclone was found and a thicker deposited layer of particles at the cyclone tip region was observed. With the introduction of the wedge, the spiral particle adhesion pattern was not observed and a reduction of particle adhered to the inner wall by up to 94% was achieved, although there was an increase in the amount of particles entering the cyclone. This demonstrates almost a complete elimination of particle adhesion onto the cyclone wall, without compromising separation efficiencies.
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Yin, Danfen, Xiaoling Zhang, Xianwei Han, Jun Yang, and Ning Hu. "Multi-Stage Particle Separation based on Microstructure Filtration and Dielectrophoresis." Micromachines 10, no. 2 (January 31, 2019): 103. http://dx.doi.org/10.3390/mi10020103.
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Particle separation is important in chemical and biomedical analysis. Among all particle separation approaches, microstructure filtration which based particles size difference has turned into one of the most commonly methods. By controlling the movement of particles, dielectrophoresis has also been widely adopted in particle separation. This work presents a microfluidic device which combines the advantages of microfilters and dielectrophoresis to separate micro-particles and cells. A three-dimensional (3D) model was developed to calculate the distributions of the electric field gradient at the two filter stages. Polystyrene particles with three different sizes were separated by micropillar array structure by applying a 35-Vpp AC voltage at 10 KHz. The blocked particles were pushed off the filters under the negative dielectrophoretic force and drag force. A mixture of Haematococcus pluvialis cells and Bracteacoccus engadinensis cells with different sizes were also successfully separated by this device, which proved that the device can separate both biological samples and polystyrene particles.
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Fan, J. L., W. H. Li, P. Zhang, and G. H. Chen. "Numerical Investigation on the Effect of the Diversion Layer on the Flow Field of the α-Type Cyclone Separator." Journal of Physics: Conference Series 2329, no. 1 (August 1, 2022): 012005. http://dx.doi.org/10.1088/1742-6596/2329/1/012005.
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Abstract The flow field stability and separation performance of the cyclone separator decrease significantly as its size increases. An inner guider was added in α-type cyclone separator, and in this paper, a numerical investigation on the gas-solid two-phase flow in the α-type cyclone was conducted. The Reynolds stress model and the DPM model were used to simulate the gas flow and the motion of particles, respectively. The influence of the guider on the velocity field, pressure field, turbulent kinetic energy field, and particle separation efficiency of the cyclone separator was analyzed. The results showed that after adding an inner guider, the tangential velocity increases, the turbulent kinetic energy decreases, the downward area of the axial airflow increases, and the number of airflow-carrying particles downward increases.
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Gregory, John. "The Role of Colloid Interactions in Solid-Liquid Separation." Water Science and Technology 27, no. 10 (May 1, 1993): 1–17. http://dx.doi.org/10.2166/wst.1993.0195.
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Forces between particles in water become especially important when the particles are in the colloidal size range (less than a few mm). To a first approximation inter-particle forces or colloid interactions are linearly dependent on particle size and they become stronger, relative to external forces, as particle size decreases. The separation of fine particles from water by processes such as coagulation, filtration and flotation can be crucially dependent on the manipulation of colloid interactions, usually to promote attachment of particles to each other or to surfaces. The most important types of colloid interaction are briefly discussed. These include van der Waals forces, electrical interaction, hydration forces, hydrophobic interaction and effects associated with adsorbed polymers, such as steric repulsion and polymer bridging. These are all short-range interactions, which have little influence on the transport of particles but which can have a major effect on collision efficiencies and on the adhesion between particles. Some examples of solid-liquid separation processes in which colloid interactions are important are given.
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You, Y., and A. K. Bertram. "Effects of molecular weight and temperature on liquid–liquid phase separation in particles containing organic species and inorganic salts." Atmospheric Chemistry and Physics 15, no. 3 (February 9, 2015): 1351–65. http://dx.doi.org/10.5194/acp-15-1351-2015.
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Abstract. Atmospheric particles containing organic species and inorganic salts may undergo liquid–liquid phase separation when the relative humidity varies between high and low values. To better understand the parameters that affect liquid–liquid phase separation in atmospheric particles, we studied the effects of molecular weight and temperature on liquid–liquid phase separation in particles containing one organic species mixed with either ammonium sulfate or ammonium bisulfate. In the molecular-weight-dependent studies, we measured liquid–liquid phase separation relative humidity (SRH) in particles containing ammonium sulfate and organic species with large molecular weights (up to 1153 Da). These results were combined with recent studies of liquid–liquid phase separation in the literature to assess if molecular weight is a useful parameter for predicting SRH. The combined results, which include results from 33 different particle types, illustrate that SRH does not depend strongly on molecular weight (i.e., a clear relationship between molecular weight and SRH was not observed). In the temperature-dependent studies, we measured liquid–liquid phase separation in particles containing ammonium sulfate mixed with 20 different organic species at 244 ± 1 K, 263 ± 1 K, and 278 ± 1 K; a few particles were also studied at 290 ± 1 K. These new results were combined with previous measurements of the same particle types at 290 ± 1 K. The combined SRH data illustrate that for the organic–ammonium sulfate particles studied, the SRH does not depend strongly on temperature. At most the SRH varied by 9.7% as the temperature varied from 290 to 244 K. The high SRH values (> 65%) in these experiments may explain the lack of temperature dependence. Since water is a plasticizer, high relative humidities can lead to high water contents, low viscosities, and high diffusion rates in the particles. For these cases, unless the temperature is very low, liquid–liquid phase separation is not expected to be kinetically inhibited. The occurrence of liquid–liquid phase separation and SRH did depend strongly on temperature over the range of 290–244 K for particles containing α,4-dihydroxy-3-methoxybenzeneacetic acid mixed with ammonium bisulfate. For this particle type, a combination of low temperatures and low water content likely favored kinetic inhabitation of the liquid–liquid phase separation by slow diffusion rates in highly viscous particles. The combined results suggest that liquid–liquid phase separation is likely a common occurrence in atmospheric particles at temperatures from 244–290 K, although particles that do not undergo liquid–liquid phase separation are also likely common.
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Surowiak, Agnieszka, Tomasz Gawenda, Agata Stempkowska, Tomasz Niedoba, and Alona Nad. "The Influence of Selected Properties of Particles in the Jigging Process of Aggregates on an Example of Chalcedonite." Minerals 10, no. 7 (June 30, 2020): 600. http://dx.doi.org/10.3390/min10070600.
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The influence of the physical, geometric and chemical properties of particles on the results of aggregate separation by means of a laboratory ring jig is presented in this paper. The experiment was based on separation of chalcedonite particles in a narrow particle size fraction composed separately of regular and irregular particles, which was prepared in accordance with patent inventions. On its basis, the geometric properties—projection diameter and (volumetric and dynamic) shape coefficients—as well as physical properties—particle density—were determined in products of the regular and irregular particles. The terminal settling velocities of the regular and irregular particles were calculated for a randomly selected sample of particles in each obtained separation product. The statistical analysis of the geometric properties of the particles allowed to evaluate the influence of these parameters on aggregate processing with respect to selection of particles homogenous in terms of their shapes. The comparison of the particle shapes’ influence on the chalcedonite feed separation effects was made by the means of the values of the shape coefficients: the dynamic and volumetric ones. Additionally, tests were carried out using Raman spectroscopy in order to determine the mechanisms of density change in the aggregate. The research goal was realised through detecting and analysing the polymorphic forms of the silica and allogenic minerals precipitated on the surface and inside the chalcedonite particles.
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Wang, Zekai, Xindong Li, Zhaolian Wang, Wanfu Huang, Guanfa Liu, Chaocong Zeng, and Lijinhong Huang. "Separation of Copper-Molybdenum Flotation Concentrate by Superconducting High-Gradient Magnetic Separation." Minerals 12, no. 10 (September 22, 2022): 1191. http://dx.doi.org/10.3390/min12101191.
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Separation of chalcopyrite from molybdenite is currently mainly carried out by flotation, but this process is costly because of the extensive use of inhibitors. This study briefly describes a 7.0T/100CGC low-temperature superconducting magnetic separator and discusses its separation principle as well as the effect of magnetic induction on chalcopyrite separation from molybdenite. A molybdenum (Mo) concentrate assaying 6.00% copper (Cu) and 19.01% Mo was magnetically sorted using a diamond-shaped steel rod medium mesh at a feed concentration of 20% and a pulp flow rate of 5 L/min from a Cu-Mo flotation concentrate with 88% of particles smaller than 23 μm using the separator. A Mo concentrate assaying 0.46% Cu and 16.28% Mo was finally obtained with a roughing (1.3 T)-cleaning (5 T) superconducting magnetic separation process. Similarly, the superconducting magnetic separator was performed to separate a Cu-Mo bulk flotation concentrate, and produced Cu concentrate assaying 19.64% Cu and 0.03% Mo from the bulk concentrate assaying 18.52% Cu and 0.39% Mo with a particle size of less than 0.074 mm. At a magnetic induction of 7 T, a pulp concentration of 20% and a feed velocity of 5 L/min, the grade and recovery of Cu in the magnetic product were 19.64% and 81.59%, respectively, whereas the grade and recovery of Mo in the non-magnetic product were 1.52% and 90.07%, respectively. Superconducting magnetic separation has potential applications for removing Cu from Mo concentrates, and separating Cu and Mo from Cu-Mo bulk flotation concentrates.
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Kudi, A. N., N. A. Fedosov, V. V. Sergeev, V. N. Dolgunin, and A. G. Tarakanov. "The Solution of the Problem of Separating a Mixture of Polydisperse Particles of Different Shapes." Vestnik Tambovskogo gosudarstvennogo tehnicheskogo universiteta 26, no. 4 (2020): 609–18. http://dx.doi.org/10.17277/vestnik.2020.04.pp.609-618.
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A technology is proposed for the separation of particles by shape in a polydisperse granular material using the effects of particle interaction in a fast shear flow on a rough slope. The technology involves the fractionation of the initial mixture by the volume of particles using the segregation effect at the first stage and the calibration of the obtained particle fractions by weight using the effect of quasi-diffusion separation (migration) in the gravity flow at the second. The final stage involves the separation of particles by shape by sieve classification of fractions according to a key geometric parameter.
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Shahrin Hisham Amirnordin, Shahrin Hisham, Adam Kasani, Mohd Faizal Mohideen Batcha, and Muhammad Rafiuddin Wahidon. "Experimental Analysis of Dual Inlet Cyclone Separator." Journal of Advanced Research in Applied Sciences and Engineering Technology 28, no. 1 (September 11, 2022): 149–60. http://dx.doi.org/10.37934/araset.28.1.149160.
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Cyclone separators are suitable to remove particles in extreme conditions with high pressure and temperature during the gas-solid separation process. The important performance of cyclone separators is determined by the separation efficiency and pressure drop. The inlet parameters including the number of inlets, inlet geometry and inlet gas velocity affects the performance of cyclone separators. In this paper, the experimental investigation has been conducted to determine the effects of dual inlet to the separation efficiency of cyclone separators. The cyclone separator was fabricated using the acrylic materials to accommodate the flow observation and trajectories inside the chamber. The experiments were conducted at 9, 11 and 13 m/s of inlet velocity using three particle sizes at 277.5, 42.5 and 625 um. Results showed that as the particle sizes increases, the separation efficiency also increases up to 94.5% for 625 um particles. The findings indicate that the dual inlet cyclone separators increases the performance of cyclone separators especially to remove fly ash in the biomass processing plant and other gas-solid process.
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Jiang, L. Y., M. Benner, and J. Bird. "Assessment of Scavenge Efficiency for a Helicopter Particle Separation System." Journal of the American Helicopter Society 57, no. 2 (April 1, 2012): 41–48. http://dx.doi.org/10.4050/jahs.57.022007.
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The effectiveness of a helicopter particle separation system has been numerically assessed at practical operating conditions and sand environments for various scenarios. The particle separation mechanism and its limitations are revealed by the predicted flow field characteristics and particle trajectories. The separation-by-inertia concept is effective for removing large particles, but problematic for small particles of diameter ≤36 μm for the configuration and operating conditions considered in the present study. It is also found that particle size, shape factor, and rebound characteristics exert substantial effects on particle scavenge efficiency. However, the effects of gravity, particle inlet velocity, inlet mass distribution, and engine-operating conditions on scavenge efficiency are minor or limited. Finally, a few suggestions for further investigation on engine particle separation systems are included.
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Liu, Xiaoyan, Hua Cheng, Hanqing Chen, Longhui Guo, Yu Fang, and Xuesong Wang. "Theoretical Study on Freezing Separation Pressure of Clay Particles with Surface Charge Action." Crystals 12, no. 9 (September 15, 2022): 1304. http://dx.doi.org/10.3390/cryst12091304.
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This study aimed to clarify the mechanism of the effect of surface charge of clay particles on the separation pressure between adjacent frozen clay particles. A general mathematical model of separation pressure between adjacent spherical clay particles was given based on the extended colloidal stability (DLVO) theory; it was introduced into the frost heave process, and the functional expression of separation pressure and freezing temperature between clay particles was derived by using the relationship between the pore throat’s radius and freezing temperature, which was verified by the existing experimental results. Finally, the effects of the freezing temperature, mineral species and solution concentration on the freezing separation pressure and ice-lens growth were analyzed. Our results show that the surface distance of adjacent charged bodies is a single-valued function of their separation pressure, but the freezing temperature is the main factor affecting the separation pressure between adjacent frozen clay particles; the separation pressure between adjacent clay particles is proportional to its surface-charge density. For the same particle spacing, the separation pressures of kaolinite and illite are not much different, but they are both about one order of magnitude lower than montmorillonite; the separation pressure between clay particles is negatively correlated with the solution concentration. When the solution concentration is less than 0.1 mol·m−3, the effect of the solution concentration on the separation pressure between particles is negligible. The research results can provide a theoretical reference for improving the existing geotechnical frost heave theory.
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PAN, LIUBIN, and PAOLO PADOAN. "Relative velocity of inertial particles in turbulent flows." Journal of Fluid Mechanics 661 (July 27, 2010): 73–107. http://dx.doi.org/10.1017/s0022112010002855.
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We present a model for the relative velocity of inertial particles in turbulent flows that provides new physical insight into this problem. Our general formulation shows that the relative velocity has contributions from two terms, referred to as the ‘generalized acceleration’ and ‘generalized shear’, because they reduce to the well-known acceleration and shear terms in the Saffman–Turner limit. The generalized shear term represents particles' memory of the flow velocity difference along their trajectories and depends on the inertial particle pair dispersion backward in time. The importance of this backward dispersion in determining the particle relative velocity is emphasized. We find that our model with a two-phase separation behaviour, an early ballistic phase and a later tracer-like phase, as found by recent simulations for the forward (in time) dispersion of inertial particle pairs, gives good fits to the measured relative speeds from simulations at low Reynolds numbers. In the monodisperse case with identical particles, the generalized acceleration term vanishes and the relative velocity is determined by the generalized shear term. At large Reynolds numbers, our model gives a St1/2-dependence of the relative velocity on the Stokes number St in the inertial range for both the ballistic behaviour and the Richardson separation law. This leads to the same inertial-range scaling for the two-phase separation that well fits the simulation results. Our calculations for the bidisperse case show that, with the friction timescale of one particle fixed, the relative speed as a function of the other particle's friction time has a dip when the two timescales are similar. This indicates that similar-size particles tend to have stronger velocity correlation than different ones. We find that the primary contribution at the dip, i.e. for similar particles, is from the generalized shear term, while the generalized acceleration term is dominant for particles of very different sizes. Future numerical studies are motivated to check the accuracy of the assumptions made in our model and to investigate the backward-in-time dispersion of inertial particle pairs in turbulent flows.
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Walter, Lindsay P., and Mathieu Francoeur. "Orientation effects on near-field radiative heat transfer between complex-shaped dielectric particles." Applied Physics Letters 121, no. 18 (October 31, 2022): 182206. http://dx.doi.org/10.1063/5.0116828.
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The effect of orientation on near-field radiative heat transfer between two complex-shaped superellipsoid particles of SiO2 is presented. The particles under study are 50 nm in radius and of variable concavity. Orientation is characterized by the degree of rotational symmetry in the two-particle systems, and the radiative conductance is calculated using the discrete system Green's function approach to account for all electromagnetic interactions. The results reveal that the total conductance in some orientations can be up to twice that of other orientations when particles are at a center-of-mass separation distance of 110 nm. Orientation effects are not significantly correlated with system rotational symmetries but are strongly correlated with the minimum vacuum gap distance between particles. As such, orientation effects on near-field radiative heat transfer are a consequence of particle topology, with more extreme topologies leading to a continuation of orientation effects at larger particle center-of-mass separation distances. The concave superellipsoid particles display significant orientation effects up to a center-of-mass separation distance approximately equal to 3.9 times the particle radius, while the convex superellipsoid particles display significant orientation effects up to a center-of-mass separation distance approximately equal to 3.2 times the particle radius. In contrast to previous anisotropic, spheroidal dipole studies, these results of complex-shaped superellipsoid particles suggest that orientation effects become negligible when heat transfer is a volumetric process for all orientations. This work is essential for understanding radiative transport between particles that have non-regular geometries or that may have geometrical defects or abnormalities.
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Lu, Shouci, Robert J. Pugh, and Eric Forssberg. "Interfacial separation of particles." China Particuology 4, no. 5 (October 2006): 258. http://dx.doi.org/10.1016/s1672-2515(07)60272-3.
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Furuuchi, Masami, and Keishi Gotoh. "Shape separation of particles." Powder Technology 73, no. 1 (November 1992): 1–9. http://dx.doi.org/10.1016/0032-5910(92)87001-q.
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