Separation Of Fine Particles Research Articles

Particle separation from road runoff by a decentralised lamella system - laboratory tests and experiences in the field.

A new decentralised settling system based on the principle of lamella separation was developed for the treatment of road runoff. Two different laboratory test methods, the DIBt (Deutsches Institut für Bautechnik) procedure and our own approach, were applied in order to evaluate the efficiency of the system based on the separation of fine mineral particles and a mixture of mineral and organic particles, respectively. Overall efficiencies (88% after DIBt and 61% according to our own method) were comparable to results obtained for commercial systems. The lamella system was then applied in the field for 1 year to treat runoff from a road area of 420 m2. The amount of solids separated that was calculated from a mass balance (10.1 kg) was consistent with the amount of sediments measured (8.6 kg). However, the average separation efficiency was only 30% in the field study. This is related to the size and composition of the particles in runoff, which are not represented well by the material used for the test procedures. It is concluded that the test methods should be improved, and that more field studies are needed in order to obtain a better understanding of the settling behaviour of particles in road runoff.

Effect of cold rolling on microstructure and mechanical properties of Cu-0,5%Cr-0,2%Zr subjected to ECAP with various NUNBERS of passes

The paper studies the effect of the combination of ECAP and cold rolling on the structure, mechanical properties and coefficient of friction of low-alloyed bronzes. It is shown that the use of ECAP together with rolling leads to the formation of a UFG structure and an increase in strength characteristics, while the coefficient of friction is increases. Subsequent heat treatment results in additional hardening by the separation of fine particles, which also reduces the coefficient of friction.

The Effects of Cold Pelleting and Separation of Fine Corn Particles on Growth Performance and Economic Return in Nursery Pigs

The Effects of Cold Pelleting and Separation of Fine Corn Particles on Growth Performance and Economic Return in Nursery Pigs

Modeling of fine coal flotation separation based on particle characteristics and hydrodynamic conditions

Flotation is a complex multifaceted process that is widely used for the separation of finely ground minerals. The theory of froth flotation is complex and is not completely understood. This fact has been brought many monitoring challenges in a coal processing plant. To solve those challenges, it is important to understand the effect of different parameters on the fine particle separation, and control flotation performance for a particular system. This study is going to indicate the effect of various parameters (particle characteristics and hydrodynamic conditions) on coal flotation responses (flotation rate constant and recovery) by different modeling techniques. A comprehensive coal flotation database was prepared for the statistical and soft computing methods. Statistical factors were used for variable selections. Results were in a good agreement with recent theoretical flotation investigations. Computational models accurately can estimate flotation rate constant and coal recovery (correlation coefficient 0.85, and 0.99, respectively). According to the results, it can be concluded that the soft computing models can overcome the complexity of process and be used as an expert system to control, and optimize parameters of coal flotation process.

Alternative dry separation of PM10 from soils for characterization by kinetic extraction: example of new Caledonian mining soils

A simple new device for dry separation of fine particulate matter from bulk soil samples is presented here. It consists of a stainless steel tube along which a nitrogen flow is imposed, resulting in the displacement of particles. Taking into account particle transport, fluid mechanics, and soil sample composition, a tube 6-m long, with a 0.04-m diameter, was found best adapted for PM10 separation. The device rapidly produced several milligrams of particulate matter, on which chemical extractions with EDTA were subsequently performed to study the kinetic parameters of extractable metals. New Caledonian mining soils were chosen here, as a case-study. Although the easily extracted metal pool represents only 0.5-6.4% of the total metal content for the elements studied (Ni, Co, Mn), the total concentrations are extremely high. This pool is therefore far from negligible, and can be troublesome in the environment. This dry technique for fine particle separation from bulk parent soil eliminates the metal-leaching risks inherent in wet filtration and should therefore ensure safe assessment of environmental quality in fine-textured, metal-contaminated soils.

Separation of Fine Particles with the Set Dimensional and Physical Characteristics by Method of the Crown Separation

In this scientific work the new method of electroseparation by means of impact on a dust fraction of the crown charge is considered. The presented device for the electromechanical separation is the main competitor for systems of the electrostatic, crown, dielectric, triboadhesion separation widespread in the industry today. Use of the electromechanical device for crown separation allows separation of fine particles with the set dimensional and physical characteristics from the stream. The main attention in the article is paid to the research of a fine fraction behaviour in the non-uniform electric field. Mechanisms of the impact of electric, gravitational, aerodynamic and other disturbances on the dust fraction (aerosols) are considered in detail. The system of the equations describing physical processes of the movement of a dust particle in the non-uniform electric field taking into account influence of the aerodynamic effort created by the "ionic" wind is presented in this work.

Economic Analysis of an Integrated Annatto Seeds-Sugarcane Biorefinery Using Supercritical CO₂ Extraction as a First Step.

Recently, supercritical fluid extraction (SFE) has been indicated to be utilized as part of a biorefinery, rather than as a stand-alone technology, since besides extracting added value compounds selectively it has been shown to have a positive effect on the downstream processing of biomass. To this extent, this work evaluates economically the encouraging experimental results regarding the use of SFE during annatto seeds valorization. Additionally, other features were discussed such as the benefits of enhancing the bioactive compounds concentration through physical processes and of integrating the proposed annatto seeds biorefinery to a hypothetical sugarcane biorefinery, which produces its essential inputs, e.g., CO2, ethanol, heat and electricity. For this, first, different configurations were modeled and simulated using the commercial simulator Aspen Plus® to determine the mass and energy balances. Next, each configuration was economically assessed using MATLAB. SFE proved to be decisive to the economic feasibility of the proposed annatto seeds-sugarcane biorefinery concept. SFE pretreatment associated with sequential fine particles separation process enabled higher bixin-rich extract production using low-pressure solvent extraction method employing ethanol, meanwhile tocotrienols-rich extract is obtained as a first product. Nevertheless, the economic evaluation showed that increasing tocotrienols-rich extract production has a more pronounced positive impact on the economic viability of the concept.

Using mineralogical characterisation and process modelling to simulate the gravity recovery of ferrochrome fines

The recovery of ferrochrome (FeCr) alloy from fine (<600μm) ferrochrome slag typically involves the use of gravity concentration, amongst other physical separation techniques. This study demonstrates the value of utilising mineralogical methods both to determine alloy composition and liberation and to assist in setting up partition surface models for a shaking table. A Mineral Liberation Analyser (MLA) was used to measure size, density, shape and liberation data of each alloy and mineral in a set of shaking table products. The amount of detailed data gathered by the MLA was sufficient to generate particle tracking analysis (PTA) data in order to simulate the recovery of alloy and mineral phases. Two flowsheet configurations were evaluated to ascertain the possibility of producing a high grade product (>97.5% metal content) comparing shaking table and Reflux Classifier performance. The results of this study show that an approach of using particle characterisation by MLA, coupled with surface partition modelling, may be a useful technique to model gravity separation of fine particles, especially where both valuable and gangue phases contain common elements in their composition.

Improvements of the cyclone separator performance by down-comer tubes

Enhancement of fine particle (PM2.5) separation is important for cyclone separators to reduce any extra purification process required at the outlet. Therefore, the present experimental research was performed to explore the performance of cyclone separators modified with down-comer tubes at solid loading rates from 0 to 8.0g/m3 with a 10m/s inlet velocity. The study proved the effectiveness of down-comer tubes in reducing the particle re-entrainment and increasing the finer separation with acceptable pressure drops, which was pronounced at low solid loading conditions. The experimental results were compared with theories of Smolik and Muschelknautz. Theories were acceptable for certain ranges, and theory breakdown was mainly due to the neglect of particle agglomeration, re-entrainment and the reduction of swirling energy, as well as the increase of wall friction due to presence of particles.

Optimization of a dual capture element magnetic separator for the purification of high velocity water flow

In this paper a magnetic separator based on the use of a cascade arrangement of two identical capture elements has been optimized and verified. Such a separator is intended for the separation of fine particles of iron from flowing water at high velocity. The optimization has concerned the search for the excitation current and the distance between the capture elements that permit the extraction of the particles from a water flow in a circular channel at an average velocity u fav = 1.05 m/s. For such optimization we have minimized the objective function that is the distance between the capture position of a particle initially situated at a specific position and the central point of the last capture element of the arrangement. To perform the minimization, we have applied the Tabu search method. To validate the obtained results experimental verification based on the control of the evolution of the captured particle buildup and the quantifying of the separated volume of particles was achieved.

Fine particle sorting and classification in the cyclonic centrifugal field

Abstract Fine particle sorting and classification are not only important processes during the powder preparation, but also vital to the sequential separation of discrete fine particles with different sizes. The moving fine particles with different sizes have different trajectories in the cyclonic centrifugal field under the actions of radial and axial forces, which inspire us to develop a novel cyclonic multi-product sorting classifier. Both particle size and mass distribution gradually increase axially from the inlet side to the outlet side and radially from the inside to the outside at the rectangular outlet of the sorting classifier. When the mean particle size of the inlet is 15.7 μm and the coefficient of variance is 90.1%, 12 different particle sizes (the minimum and maximum particle sizes are 8.41 and 26.16 μm, respectively) with better monodispersion are obtained, all products achieve a particle coefficient of variance below 40%. An effective calculation method was used to represent the overall sorting and classification performance of sorting classifiers with different height. The results show that the best height is 5 times as high as the rectangular inlet, and the optimum gas flow is 30–60 m 3 /h with the pressure drop not exceed of 80 Pa. The present study could also serve as a useful guide in the industrial sequential separation and capture of fine particles of different sizes. Notably, it may exhibit a high potential for the control of PM 2.5 throughout studies in future.

Mineral beneficiation by ionic microbubble in continuous plant prototype: Efficiency and its analysis by kinetic model

Microbubbles are miniature gas bubbles of less than 100μm diameter in liquid. The performance of ionic microbubble for fine particle separation is investigated and reported in the paper. The effects of different operating variables and physicochemical properties of liquid on the separation characteristics of ionic microbubble are enunciated. A phenomenological kinetic model based on collision, attachment and detachment mechanisms of fine particle is developed to analyze the flotation characteristics of the ionic microbubbles. Generalized correlations for flotation rate constant and induction time are also developed based on the physicochemical properties of microbubble–particle mixture. It is concluded that ionic microbubble is highly efficient for removal of fine particles of opposite charge. The findings from this research may be helpful to understand and explain the process better and possibly can be used to modify and improve the microbubble aided flotation process.

Arsenic removal from contaminated soils for recycling via oil agglomerate flotation

In this study, a flotation process is proposed for separating the arsenic-bearing minerals to recycle the soil surrounding the Janghang refinery in South Korea, which contains a high level of arsenic. To maximize the arsenic recovery, several experimental parameters were systematically investigated. X-ray diffraction revealed that the contaminated soil was mainly composed of arsenopyrite (FeAsS), arsenic trioxide (As4O6), arsenic pentoxide (As2O5), and quartz (SiO2). Flotation experiments with various concentrations of potassium amyl xanthate (PAX) showed that arsenic recovery increased with increasing PAX concentration. The addition of activators (Na2S, CuSO4, Na2S+CuSO4) in pulp pH greatly increased the arsenic recovery. In addition, oil agglomerate flotation was conducted to enhance the arsenic recovery by improving the separation of fine particles. The results showed that arsenic recovery increased with increasing nonpolar oil concentration. Based on the results obtained from the optimization tests, a flotation process by which the arsenic-contaminated soils can be recycled was successfully designed.

Modular mini-hydrocyclone desilter type of 30mm: An experimental and optimization study

Mini-hydrocyclones are separators widely investigated with a view to expanding their applications in operations that require efficient separation of fine particles. The purpose of this study was to analyze the effects of design and operating variables, including the vortex finder length and height of the cylindrical body, cone frustum angle, underflow diameter and feed pressure, on the separation efficiency of a modular hydrocyclone with a characteristic diameter of 30 mm especially developed for use in the petroleum industry. The particulate matter consisted of phosphate rock with a density of 3.15 g/cm3 and an average diameter of 4.5 μm, used at a concentration of 0.5 vol% in the preparation of the suspension. The results were analyzed statistically and correlations or empirical models were generated. The proposed empirical models offered a good description of the collected experimental data. A methodology for multi-objective optimization of these models was used and an optimal geometry was proposed. The optimal geometry showed a total separation efficiency of more than 89% and a flow ratio of less than 35%.

Prediction of Separation Performance of Dry High Intensity Magnetic Separator for Processing of Para-Magnetic Minerals

High intensity dry magnetic separators are gaining popularity for the separation of para-magnetic minerals due to the cost economic factor. Induced roll magnetic separator is found to be an effective dry separator for the separation of fine particles. Separation efficiency of this separator depends on mineral characteristics and the design features of equipment along with the optimization of process variables. Present investigation focuses on the prediction and validation of separation performance of minerals while treating in induced roll magnetic separator. Prediction of the separation is expressed in terms of separation angle at which a particle leaves the rotor surface by using a modified particle flow model derived by Cakir. The validation of the model is carried by capturing the particle trajectory using an image analyzer. It is found that Cakir’s mathematical model produces reliable results and a new model is proposed to increase the reliability of separation angle prediction by including the particle shape factor.

Application of Minihydrocyclones in Methanol‐to‐Olefin Process Wastewater Treatment

AbstractA significant amount of wastewater containing fine catalyst particles is produced in the methanol‐to‐olefin (MTO) process, which restricts the long‐period operation of the processing unit. To address this key problem, a minihydrocyclone was designed for MTO wastewater treatment and tested in the laboratory. Good separation performance and a small cut diameter were achieved under certain feed conditions. Furthermore, a group composed of 300 parallel‐arranged minihydrocyclones was applied to the industrial unit in the MTO quench water treatment. The obtained results indicated that the separation efficiency and precision of the minihydrocyclone can meet the requirements of fine catalyst particle separation, and the designed minihydrocyclone group with reasonable parallel configuration exerted an outstanding application effect on the treatment of MTO quench water.

Separation of fine particles at different frequencies and HRTs using acoustic standing waves

The objective of this study was to evaluate the separation of fine particles using several frequencies and hydraulic retention times (HRTs) in an acoustic standing wave reactor without any separate cooling devices. The acoustic standing wave reactor consisted of sufficient space (over 100 mm) between the transducer and reflector, resulting in a slight increase in temperature. However, the increase in temperature did not affect the formation of standing waves and particle aggregations in our experiments. The results indicated that the turbidity removal efficiencies of fine kaolin particles, when using frequencies of 580 kHz, 1, and 2 MHz, increased with longer standing wave operation time. Especially, the turbidity removal efficiencies for 1 and 2 MHz were higher than that for 580 kHz because the wavelength (λ) of the 580 kHz wave was longer than that of the 1 and 2 MHz waves. Furthermore, the turbidity removal efficiency of kaolin in a continuous reactor improved with increasing hydraulic retention times (HRTs), and the reactor was more effective with 1 and 2 MHz used in parallel instead of 1 and 2 MHz used individually under the same HRT conditions with the entrance length (EL) having no adverse effect.

Separation of fine organic particles by a low-pressure hydrocyclone (LPH)

The separation performance of a low-pressure hydrocyclone was tested using fine organic particles from 1 to 700μm. The dimensions of the low-pressure hydrocyclone were an inflow diameter of 30mm, a cylinder length of 575mm, an overflow diameter of 60mm, an underflow diameter of 50mm, a cylinder diameter of 335mm and a cone angle of 68°. The low-pressure hydrocyclone was operated with a lower inlet pressure (average 1.38–5.56kPa) that could be maintained under water level differences that ranged from 17.5 to 53.5cm between the water surface of the feeding mass cylinder and the middle of the inlet pipe of the low-pressure hydrocyclone. By varying the inflow rate, underflow ratio and feed concentration, the separation performance of the low-pressure hydrocyclone was affected. The separation performances were determined from total separation efficiency and grade efficiency. Separation performances were determined according to the different inflow rates of 400, 600, 800 and 1000mls−1 and their respective underflow ratios that ranged from 5% to 30%. The maximum total separation efficiencies for each inflow rate were 41%, 46% and 46% at 400, 800 and 1000mls−1 inflow rates, respectively, and at underflow rates of 30% of the inflow rates. In addition, a total separation efficiency of 46% was employed at 600mls−1 of inflow rate and with an underflow rate of 25% its inflow rate. As the feed concentration increased from 25 to 150mgl−1, the separation performances were gradually decreased. For the fine particles ranging 1–200μm, the grade efficiency was higher at the higher inflow rate (higher than 600mls−1) and higher underflow rate. However, for the coarse particles ranging 400–700μm, the grade efficiency was higher at the lower inflow rate (lower than 600mls−1) and higher underflow rate. The cut-point (d50) values ranged from 30 to 200μm for a feed size range of 1–700μm. The Response Surface Method (RSM) model predicted an optimum operating inflow rate and underflow ratio of 721mls−1 of inflow rate and 30%, respectively, for the low-pressure hydrocyclone at a maximum total separation efficiency. Based on these findings, further design and operating adaptation of low-pressure hydrocyclones used for fine solids removal in recirculating aquaculture systems is expected.

Process monitoring and control for constant separation conditions in centrifugal classification of fine particles

Due to their high centrifugal acceleration tubular bowl centrifuges enable the separation and classification of fine particles. However, this type of centrifuge which is operated in a semi-continuous mode has a major disadvantage: sediment buildup in the rotor leads to a successive degradation of separation conditions over process time. In this study, a light scattering sensor was used to monitor this mechanism online by measuring the solids concentration in the overflow. Polyvinylchloride (low micrometer range) and fumed silica particles (nanometer range) served as experimental products. By incorporating the sensor signal in a control loop with the speed of the centrifuge, the mentioned drawback was compensated. As a result, grade efficiency and product loss were kept constant up to a high filling level of the rotor. It is outlined how this technology can be used for very demanding classification tasks, especially in case of fine, low-density materials.

A new method for separation, characterization, and quantification of natural nanoparticles from soils

Properties and distribution dynamics of nanoparticles are pertinent to ecological and human health. Wide variation in particle density confounds their accurate separation for study. The objective of this study was to develop a fine-particle separation protocol requiring no constant density assumption. Six soils with contrasting properties were chosen for study. Size distributions of suspended particles following centrifugation were assessed using dynamic light scattering. Mineralogy was determined by X-ray diffraction. Particle characteristics were examined using transmission electron microscopy. A significant pooled logarithmic relationship was found between centrifugation speed and particle-size distribution. Nanoparticles (<100 nm) became dominant by fractional volume at widely differing separation energies among the six soils. However, relations were strong between separation energies and fractional volume for individual soils. Bi- and tri-modal-size distributions within suspensions were related to density differences of soil components. Re-aggregation at high separation energy was apparent for the tropical soils. Light-scattering, UV–Visible absorbance, and chemical analyses distinguished samples of high hematite content from those without hematite. These results indicate that dynamic light scattering in conjunction with a standard centrifuge regimen provides a practical means of collecting colloidal particles within a targeted size range, compensating for natural variations among the soil samples.