Search

Efficient enrichment of macerals improves the liquefaction efficiency of low-rank coal. The paper studied the characteristics of Shendong low-rank coal, including proximate and ultimate analyses, size and density compositions, and petrographic analysis, as well as the migration regularity of narrow particle size of low-rank coal macerals in the enhanced gravity field. On this basis, a novel classification separation process for low-rank coal macerals using Krebs hydrocyclone and enhanced gravity separator was proposed. The classification size was determined to be 0.074 mm and Krebs hydrocyclone achieved a satisfactory classification effect with a classification efficiency of 84.72%. Based on the enhanced gravity separation results of macerals from hydrocyclone underflow and overflow, the optimal sorting solutions for underflow and overflow were obtained through response surface analysis, respectively. Through the novel classification separation process, the vitrinite content of clean coal has been increased from 46.60% to 61.33% with an outstanding recovery of 77.40%. The novel classification separation process using hydrocyclone and enhanced gravity separator develops an excellent enrichment effect for low-rank coal macerals, which also provides a prospective approach for the cleaner utilization of low-rank coal. [ABSTRACT FROM AUTHOR]

Cyclones are pivotal in mechanical process engineering and crucial in the complex field of separation technology. Their robustness and compact spatial requirements render them universally applicable and versatile across various industrial domains. Depending on the utilized fluid and field of application, both gas-based cyclones and hydrocyclones (HCs) are well established. Regarding HC design, enduring elongated flat cones have seen minimal alterations in shape and structure since their introduction over more than a hundred years ago. Experimental investigations regarding unconventional cone designs within scientific studies remain the exception. Therefore, this study focuses on alternative geometric configurations of the separation chambers and highlights their impact on separation and energy efficiency. To achieve this objective, different geometric shapes are investigated and retrofitted into HCs. The geometric foundation is derived from upcycled glass bottles. The repurposed bottles with a volume of 750 mL are used in conjunction with an inlet part, following the established Rietema design. Experimental tests are conducted with dilute phase separation, using 0.1–200 µm test particles in water. Comparisons between a bottle-based HC and a conventional Rietema design were conducted, establishing a benchmark against the standard. The findings revealed a noticeable correlation between separation efficiency and cone geometry. Conical designs demonstrated enhanced separation, particularly at lower volume flows. At the highest volume flow of 75 L min−1, the best performing bottle cyclones showed separation efficiencies of 78.5%, 78.4% and 77.9% and therefore are in a competitive range with 78.0% efficiency, achieved using the commercial Rietema design. Minimal disparities in cut sizes were observed in terms of separation grade efficiency among the models tested. Variations in separation efficiency and fractional efficiency curves indicated nuanced differences in classification efficiency. [ABSTRACT FROM AUTHOR]

The underflow entrainment of fine particles occurs during the hydrocyclone separation process, resulting in a "fishhook" effect on grade efficiency. Traditional efficiency models fail to address this phenomenon. This study examines the tracking behavior of fine particles, using variations in centrifugal settling velocity to characterize separation performance. The effect of this behavior on particle separation is quantified through a tracking coefficient for small particles and an entrainment coefficient for large particles, together forming a novel efficiency calculation model. The experimental research shows that the new model is applicable for the efficiency calculation of particles with different shapes, and can calculate grade efficiency curves with fishhook segments. By comparing with the existing research results, the accuracy and universality of the new model have been demonstrated. This model facilitates the accurate computation of grade efficiency curves, thereby significantly enhancing the precision of efficiency calculations, which provides guidance for the design and selection of hydrocyclones. [ABSTRACT FROM AUTHOR]

Solid fluidization is a promising method for the development of marine hydrate resources. The back pressure makes it difficult to backfill the separated sand to the well bottom, resulting in a decrease in separation performance and serious failure of hydrocyclone. This study is intended to study the effect of underflow diameter on the performance of the hydrocyclone by computational fluid dynamics method. The results show that with the increase of back pressure, the split ratio basically decreases linearly, and the LAVV gradually increases. Under the same back pressure, the underflow diameter is larger, the pressure drop is smaller. No matter how large the underflow diameter is, the hydrocyclone may fail once back pressure exceeds 60 kPa. Under the same back pressure, the larger the underflow diameter is, the higher the desanding efficiency is, while the purification efficiency is opposite. When back pressure exceeds 60 kPa, the desanding efficiency drops sharply, while the purification efficiency remains basically unchanged. This study is applicable to downhole in-situ separation for solid fluidization of marine hydrate. The purpose of this study is to guide the structure design of hydrocyclone and the optimization of hydrate production process parameters. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An attempt has been made to develop a non-intrusive and robust technique for online detection of roping in hydrocyclones using commercially available vibration-based sensors. A 50.8 mm diameter hydrocyclone was operated with two different silica slurry size distributions till roping was achieved in the underflow. Vibration signals were captured simultaneously at the spigot region for various operating conditions. Empirical Mode Decomposition (EMD) was applied to the raw vibration signal for extracting Intrinsic Mode Function (IMF) within the frequency range of the natural frequency of the hydrocyclone. Subsequently, Power Spectral Density (PSD) and frequency spectrum were computed along the axial direction. The Grms (square root of the area under PSD) and peak frequency values were found to be different for the spray and rope discharge which were used for detecting roping conditions. The differences were considered to be associated with the changes in the axial velocity fluctuations of the air core at the spigot region. Further, a flowchart has been proposed based on the methodology suggested in this work, which has the potential for online detection of roping in the hydrocyclone. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydrocyclones are widely used in the separation of two-phase immiscible mixtures. In various application scenarios, three-phase hydrocyclones (3PH) are often urgently needed. In this work, the typical 3PHs are classified into six categories according to their structural characteristics. A comprehensive analysis of their structural feature, design points and processing difficulties are carried out to provide guidance for the design of 3PH structure. On this basis, the technical and economic analyses are conducted based on operating parameters, separation performance and pressure loss. Furthermore, the current problems and future development directions of the 3PH separation technology are summarized. Hydrocyclones mounted in series are suitable for application scenarios with low requirements for floor space and energy consumption. The 3PH of constructing axially adjacent two-stage cyclone chambers is applicable for long and narrow spaces such as downhole separation. The 3PHs with two radially nested cyclone chambers or one independent cyclone chamber are applicable to limited spaces such as offshore platforms. Considering the comprehensive performance of different 3PHs, the 3PH with a single three-phase cyclone chamber is more recommended in practical applications. The analysis results can provide theoretical and technical support for the design, optimization and technical promotion of high-efficiency 3PH separation technology. [ABSTRACT FROM AUTHOR]

The work conducted flow field analysis of a typical hydrocyclone (φ500 type) in the Coal Processing Plant using CFD simulation, including hydrocyclone modeling, flow field development, static pressure distribution, three-dimensional velocity, and air column development. Besides, the effects of influential factors on the classification effect of hydrocyclone were studied. On this basis, a novel hydrocyclone model was developed and simulated for the ultrafine classification of coal slurry. The static pressure and velocity in the typical hydrocyclone have good symmetry and certain regularity. Decreasing the overflow pipe diameter and cone angle, while increasing the underflow pipe diameter, cylindrical section height, and feed rate will increase the classification efficiency of hydrocyclone. The novel hydrocyclone designed of annular feeding, small cone angle, and large cone bottom reduces energy consumption, decreases classification size, and improves classification accuracy. CFD simulation results show that the novel hydrocyclone has higher classification efficiency and smaller classification size over the typical hydrocyclone. The novel hydrocyclone develops an excellent ultrafine classification effect of coal slurry and provides a prospective approach for the industrial application of hydrocyclone in the fine coal ultrafine classification process. [ABSTRACT FROM AUTHOR]

Hydrocyclones can be used to concentrate the entrained sands in sewage and alleviate the clogging and erosion of the drainage network, but in practical application, there are problems such as low concentrations of underflow and a high content of fine particles, which cause a significant load on the subsequent sand dewatering and recycling. This paper designs five spigot structures of hydrocyclones and investigates the separation performance by numerical simulation, aiming to improve the applicability of hydrocyclones in the sewage treatment process by optimizing the spigot structure. The research results show that a large cone spigot delays the external downward swirling flow and reduces fine particle content in the underflow, but its effective separation space is reduced, and the turbulence in the cone section area is more intensive, which influences the separation accuracy. An elongated spigot has a reduced underflow water distribution; fine particles are more enriched in the internal swirling flow, and the underflow recoveries of 1 μm and 5 μm particles drop by 2.34% and 2.31%. The spigot structure affects the downward fluid and air intake states; complicated spigot structures contribute to increasing the resistance of particle discharge through underflow, alleviating fine particle misplacement. [ABSTRACT FROM AUTHOR]

Harmonization in the analytical framework is needed to detect, define and further categorize plastics released into the environment. In the range of particles smaller than 200 μm, hydrocyclones (HCs) have proven their capacity in removing microplastics efficiently by offering technical advantages at low operational costs. This publication aims to expand scientific knowledge by introducing four commercially available, low-priced microplastics to a pilot-scale HC setting. The physicochemical characteristics of particles as well as the separation efficiency of the test rig were investigated in depth. Particles with a density of >1000 kg/m3 passed the primary vortex and were discharged into the underflow, allowing us to employ standard mode operation. Particles with a density of <1000 kg/m3 entered the secondary vortex and were removed through the overflow. As expected, separation efficiencies were found to be higher for particles revealing a greater density difference when compared with the mobile phase water. Furthermore, an increase in the inlet volume flow revealed significant positive impacts on the separation efficiency for three plastics to a certain threshold. Data on standard and reverse mode operations presented in this publication can lay out an important source for the harmonization and standardization of future HC research, with the goal of overcoming plastic pollution by developing economically competitive separation processes. [ABSTRACT FROM AUTHOR]

A method to improve the classification performance of the cyclone was proposed by modifying the cone section of the conventional cyclone to address the problems of low classification accuracy and high operating energy consumption. The influence of linear, parabolic, and hyperbolic conical structures of cyclones on the internal flow field characteristics and separation performance was presented through numerical calculation methods. The numerical results show that using a parabolic cone can reduce the tangential and axial velocities of the cyclone, reduce the probability of turbulence, and effectively improve the stability of the flow field. The internal flow field of the hyperbolic cone is unstable, which is not conducive to the smooth operation of particles. The zero speed envelope surface of the parabolic cyclone moves outward, increasing the space for fine internal swirling flow and allowing for sufficient separation of fine particles, resulting in a certain improvement in classification accuracy. Compared to conventional and hyperbolic models, parabolic cyclones have lower turbulence intensity and effectively improve particle stability* At the same time, the steepness index of parabolic cyclones has been increased from 0. 61 to 0. 72, greatly improving the classification accuracy of cyclones. Due to the increase in separation space, the cutting particle size has slightly increased. [ABSTRACT FROM AUTHOR]

A semi-industrial scale hydrocyclone with a 250 mm internal diameter was used to concentrate medium-grade celestine ore (75%–85% celestine) from the Montevive deposit of Granada (Spain) using a dense ferrosilicon (FeSi) medium. For this purpose, a Box–Behnken factorial design (BBD) was carried out, with the response variable being the Sr concentration measured by X-ray fluorescence (XRF), as well as the concentration of celestine measured by X-ray diffraction (XRD) of the mineral collected from the under (sunk) stream of the hydrocyclone. The experimental factors to be optimised were the density of the medium in the mixing tank (water, FeSi, and feed mineral) varying from 2.7 to 2.9 kg/L, the hydrocyclone inlet pressure from 0.8 to 1.2 bar, and the hydrocyclone inclination (from 15° to 25° from the horizontal). The range of densities of the dense medium to be tested was determined from previous sink–float experiments using medium-grade ore, in which the distribution of mineral phases with different particle size fractions was determined. To evaluate the separation behaviour, the following parameters were considered: the enrichment ratio (E), the tailings discarding ratio (R), and the mineral processing recovery (ε). From the factorial design and the response surface, the optimum parameters maximising celestine concentration in the under stream (78%), were determined. These optimised parameters were: a density of 2.75 kg/L for the dense medium, an inlet pressure of 1.05 bar, and a hydrocyclone inclination varying from 18° to 20°. Under these conditions, a 94% recovery of celestine (68% Sr) can be achieved. These results show that medium-grade celestine ore, accumulated in mine tailings dumps, can be effectively concentrated using DMS hydrocyclones and that the operating parameters can be optimised using a factorial experiment design. This study can contribute to reducing overexploitation of strategic mineral resources, avoiding blasting and environmentally damaging clearing, by applying a simple and sustainable technique. [ABSTRACT FROM AUTHOR]

Hydrocyclone is a common solid-liquid separation equipment, but due to its own structural limitations, the classification accuracy in the cyclone is not high. As the primary channel for multiphase flow entering the cyclone, the feed body has a significant impact on the classification performance of the cyclone. However, the problems of turbulent diffusion caused by high turbulent flow field in the feed body and low particle classification accuracy caused by collision and compression between particles urgently need to be solved. Therefore, a composite curve feed structure cyclone has been designed, which reduces the proportion of fine particles entering the bottom flow by regulating the internal flow field and particle motion in the feed body, thereby achieving the goal of improving classification accuracy. The numerical analysis method was used to explore the flow field characteristics and classification performance characteristics of five types of hydrocyclones with different feed-body structure: linear feed body, involute feed body, vortex feed body, linear guide feed body, and composite curve feed body. The superiority of the hydrocyclone with composite curve feed body was highlighted, and comprehensive exploration was conducted from the aspects of pressure field, velocity field, classification efficiency, and so on. Finally, experimental exploration was conducted on it. The results show that the composite curve feed body structure has better fine particle classification performance compared to other feed body structures, and the internal flow field is more stable. At the same time, the isobaric surface distribution shows regular changes, and the particle movement is more stable. The tangential velocity of the composite curve feed body is significantly higher than that of other feed body structures, and the particles obtain greater centrifugal driving force, making them easier to classify. The experimental results show that the separation efficiency of the compound curve feed body hydrocyclone is 46.32%, which is 7.32% higher than that of the conventional feed body hydrocyclone, and the content of -24 µm particles in the compound curve underflow is 15.07% lower than that of the conventional one. The content of -24 jum particles in the overflow is 3.39% higher than that in the conventional type, and the particle classification accuracy is greatly improved. [ABSTRACT FROM AUTHOR]

When the oilfield enters the middle and late stages of development, the moisture content of the produced liquid rises sharply. The primary problem that needs to be solved in the later stage of development is how to reduce the water content and improve the recovery rate. Hydrocyclone technology, gravity separation technology or other oil-water separation processes are used for downhole oil-water separation to achieve pre-separation of the moisture liquid downhole, so as to produce a lower water-water mixture, which has great application prospects for high water-cut oilfields. Through the brief analysis and summary of the research status of downhole oil-water separation device, the problems and challenges of the current downhole oil-water separation device were pointed out, and the prospect was made to provide a certain reference for its development. [ABSTRACT FROM AUTHOR]

In response to the issue of resource waste caused by the inability to recover and utilize microfine low-grade gold in the sulfur separation operation process of cyanide tailings in a gold production enterprise, a systematic experimental study was conducted. Based on the existing sulfur separation system, cyanide tailings and sulfur concentrate were used as experimental objects to test the gold recovery conditions of the technical scheme, forming a technical scheme for producing high-grade gold and sulfur concentrate and low-grade gold and sulfur concentrate through the enrichment of cyanide tailings by the existing sulfur separation system and further classification with a hydrocyclone. The scheme has the advantages of low cost and easy implementation for industrialization. After on-site transformation, two products were produced: high-grade gold and sulfur concentrate with a gold grade greater than 3.0 g/t and a sulfur grade greater than 46.5 %,and low-grade gold and sulfur concentrate with a sulfur grade greater than 46.5 %,which maximized the economic benefits. [ABSTRACT FROM AUTHOR]

Nowadays microplastics have become a significant environmental concern, impacting both freshwater and marine ecosystems. In response to this issue, extensive research has been conducted to explore methods for separating microplastics from water. One area of investigation involves the use of computational fluid dynamics (CFD) models to study hydrocyclones and their intricate flow patterns. In this study, CFD was systematically used to examine various hydrocyclone designs with different geometrical parameters, including the ratios of cylindrical diameter to underflow diameter and overflow diameter, the cone to cylindrical height ratio, and the inlet angle. The efficiency of these hydrocyclones has been evaluated based on key performance metrics, including microplastics recovery percentage, water split percentage, and pressure drop. The results of this study have revealed noteworthy findings. Moreover, statistical analysis, specifically the analysis of variance (ANOVA), was employed to determine the significance of various geometric parameters on microplastics separation within the hydrocyclone. As a result of this comprehensive investigation, an optimized hydrocyclone design was proposed. This optimized hydrocyclone featured an underflow diameter to diameter of the cylindrical ratio of 0.264, an overflow diameter to diameter of the cylindrical ratio of 0.3, a cone to cylindrical height ratio of 13.22:70.78, and a tangential inlet. This configuration achieved a remarkable 76% microplastics recovery, a 52% water split, and a pressure drop of 82,340 Pa.

The company Elixir Prahovo uses dry grinding of raw phosphate in its production process. However, due to increased moisture in the raw phosphate causing difficulties in the dry grinding phase, the possibility of introducing wet grinding is being considered at the industrial plant in Prahovo. The moisture content of the incoming raw phosphate varies from barge to barge, ranging between 5-10% H2O, which is very high for the dry grinding process and create certain problems in the transportation system (the system of apron conveyors). To assess the possibility of wet grinding of phosphates, predefined laboratory tests were conducted at the Department of Mineral Processing of the Faculty of Mining and Geology in Belgrade. This paper presents a portion of the results obtained during the aforementioned tests, which relate to the tested sample and its processing, as well as the determination of the particle size distribution of the initial sample, density, and bulk mass of phosphate ore. T In further investigations, grindability tests were conducted in a laboratory ball mill, and hydrocyclone tests were conducted on the ground phosphate in a laboratory hydrocyclone. Based on the results of these investigations, the necessary technological parameters have been determined to propose a scheme for the technological process of wet grinding and classification of phosphate. These parameters primarily relate to the material distribution in the hydrocyclone, pulp density in classification, and the particle size distribution of the ground phosphate.

Harmonization in the analytical framework is needed to detect, define and further categorize plastics released into the environment. In the range of particles smaller than 200 μm, hydrocyclones (HCs) have proven their capacity in removing microplastics efficiently by offering technical advantages at low operational costs. This publication aims to expand scientific knowledge by introducing four commercially available, low-priced microplastics to a pilot-scale HC setting. The physicochemical characteristics of particles as well as the separation efficiency of the test rig were investigated in depth. Particles with a density of >1000 kg/m3 passed the primary vortex and were discharged into the underflow, allowing us to employ standard mode operation. Particles with a density of 3 entered the secondary vortex and were removed through the overflow. As expected, separation efficiencies were found to be higher for particles revealing a greater density difference when compared with the mobile phase water. Furthermore, an increase in the inlet volume flow revealed significant positive impacts on the separation efficiency for three plastics to a certain threshold. Data on standard and reverse mode operations presented in this publication can lay out an important source for the harmonization and standardization of future HC research, with the goal of overcoming plastic pollution by developing economically competitive separation processes.

• Eddy leaching technique was developed to treat heavy metal-contaminated soil. • Concentration of heavy metals in soil reduced as particle size increased. • Highest separation efficiency of hydrocyclone was 84.7%. • Enhanced desorption of heavy metals by eddy leaching compared to OAPE. An eddy deep leaching technology was developed in this paper to address the challenge of treating heavy metal contaminants in industrial mining areas. The desorption effect of As, Cd, Sb and Pb was investigated utilizing chemical leaching and physical eddy techniques. It was found that the heavy metals concentration increased with decreasing particle size. The highest proportion of Cd in the form distribution of soil was in the bound to iron and manganese oxides, while the maximum proportion of As, Sb and Pb were in the residual. The optimal solid-liquid ratio of the hydrocyclone was 1:20, and the corresponding separation efficiency and flow rate were 84.7% and 1.76 m3/hr, respectively. The grade efficiency of soil particle separation increases with particle size and exceeds 99% for particles above 1,000 µm. Leaching experiments have revealed that oxalic acid (OA) and a combination of oxalic acid and EDTA (OAPE) were more efficient than citric acid (CA) and a combination of citric acid and EDTA (CAPE) for the desorption of heavy metals, respectively. The comparison of OAPE and eddy leaching found that the latter improved the desorption efficiency by 9.4%, 7.5%, 7.2% and 7.8% for As, Cd, Sb and Pb compared to the former, respectively. The results demonstrated that the eddy leaching technique could further enhance the desorption efficiency of heavy metals. It is expected to provide technical support for soil remediation with reduced usage of leaching agents. [Display omitted] [ABSTRACT FROM AUTHOR]

A pipe hydrocyclone is easy to disassemble in agricultural machinery. Spiral flow can be generated to drive the movement of impurities in the pipe, thereby effectively reducing the accumulation of impurities. Different structural parameters can form differences in the annular gap space of hydrocyclones. The structure of the annular gap space can also dominate the flow field distribution and swirl efficiency. Therefore, this article aims to explore the annular gap spiral flow formed by the hydrocyclones with different structural parameters using physical model experiments. The research results show that the structural parameters of hydrocyclone were dominated by the magnitude and dispersion of axial, radial and circumferential flow rates, where the most contribution was the radial and circumferential flow rates. There was no change in the overall distribution pattern of the annular gap flow field. Furthermore, there was the roughly same variation trend of axial average velocity and standard deviation along the water flow direction under different structural parameters. Both showed a gradually decreasing trend along the way. However there was a relatively small amplitude of the decrease in the axial average velocity along the way. The standard deviation of the cross-section gradually decreased in the constant diameter of the hydrocyclone, as the length increased, whereas, the axial average velocity increased. However, there were relatively small changes in the standard deviation and axial average velocity. Both axial average flow velocity and standard deviation increased in the constant length of the hydrocyclone, as the diameter increased, whereas, there was a relatively large variation in their amplitude. The radial average velocity and standard deviation showed a "V" shaped trend of decreasing first and then increasing along the flow under different structural parameters. The radial average velocity and flow velocity fluctuation of each section gradually increased in the constant diameter of hydrocyclone, as the length increased, but the increase was relatively small. The radial average velocity decreased in the constant length of hydrocyclone, as the diameter increased, but the flow velocity fluctuation of each section increased gradually. The circumferential average velocity and standard deviation of different structural parameters showed a gradually increasing trend along the water flow, but their growth rate in the first half of the annular gap was relatively small. The circumferential average velocity and flow velocity fluctuation showed a gradually increasing trend in the constant diameter of hydrocyclone, as the length increased, but the increased amplitude of both was relatively small. The circumferential average velocity and flow velocity fluctuation showed a gradually increasing trend in the constant length of hydrocyclone, as the diameter increased. Both energy consumption and rotation efficiency increased significantly, as the length or diameter of hydrocyclone increased. In addition, there was a higher increase rate with the diameter than that with the length. This experiment demonstrated that the hydrocyclone with a structural parameter of 70 mm×100 mm presented the highest starting efficiency. The optimal structural parameter of hydrocyclone was in the size of 70 mm×100 mm. This finding can provide a strong theoretical basis and reference for the selection and structural optimization of the hydrocyclone. [ABSTRACT FROM AUTHOR]

An attempt has been made to develop a non-intrusive and robust technique for online process monitoring of hydrocyclones using commercially available vibration sensors. Vibration signals were captured first at the spigots of 50.8 mm and 76.2 mm diameter hydrocyclones while using water only at different operating conditions. For denoising the captured raw vibration signals, a wavelet-based method coupled with median filtering-based technique was used. The Root Mean Square (RMS) values of vibration accelerations induced in the hydrocyclone were found to be proportional to the total volumetric feed rate. Based on this observation, it has been demonstrated how suitable empirical correlations can be developed which can ultimately be used as an online process monitoring tool for hydrocyclones. [ABSTRACT FROM AUTHOR]

This study introduced Krebs hydrocyclone into fine coal EGS process, examined the ultrafine classification effect of Krebs hydrocyclone by single-factor tests and orthogonal tests, and evaluated the fine coal EGS effect after ultrafine classification. Besides, the flow field characteristics in Krebs hydrocyclone were explored by simulation. The optimal grading efficiency of the verification test is 91.32%, and the content of ultrafine particles can be reduced to 1.01%, which prove the excellent ultrafine classification effect of Krebs hydrocyclone. The optimal combustible recovery and ash removal rate are 94.29% and 98.52%, respectively, and when the clean coal ash drops below 10%, the combustible recovery is more than 80%, which reveal that the sorting indexes of fine coal EGS after ultrafine classification are much better than that of unclassified coal. Both the static pressure and velocity in Krebs hydrocyclone have good symmetry and certain regularity. Due to the use of water as a separation medium, the introduction of Krebs hydrocyclone in the fine coal EGS process provides an effective and prospective approach for the industrial application of enhanced gravity separators in the fine coal washing process, especially in the face of increasingly serious environmental problems. [ABSTRACT FROM AUTHOR]

The real media encountered in oil and gas production are usually dispersed, i.e., they are systems consisting of at least two phases, with one of the phases being distributed into the other. Production, collection and transportation of oil and gas are based on multiphase technology, including the processes of lifting from the reservoir, transportation to separation points, separation and infield transport of multiphase mixtures, which consist of oil, gas, formation water and mechanical impurities. In most technological processes of oil and gas production and transport of hydrocarbons, the separation of dispersed systems is necessary. In practice, the unsuitability of hydrocyclone technology for separating emulsions has been established, although hydrocyclones are effectively used for cleaning suspensions, for separating solid particles from liquids, for example, for cleaning drilling fluids from sludge. Recent studies have established that cylindrical multiphase flows are based on the interaction of continuous and dispersed phases, the driving force of which is an additional shear force directed towards the flow axis. In the paper, according to the multiphase technology, the reason for the low efficiency of hydrocyclones for multiphase disperse systems was analyzed. The condition of equality of the shear and centrifugal forces during the operation of the hydrocyclone is shown. It has been established that, based on the correct choice of technological parameters, it is possible to avoid the negative effect of the shear force in cylindrical flows on the operation of hydrocyclones. [ABSTRACT FROM AUTHOR]

Aiming at the problem of "entrainment fine particles in underflow" of hydrocyclone in grinding and classification process, a hydrocyclone with spiral vanes (the SV hydrocyclone) was proposed. The CFD techniques were used to study the pressure field, velocity field, turbulence field, particle field and classification efficiency of hydrocyclones with spiral vanes of different widths. The results show that the pressure drop, axial velocity, tangential velocity, turbulence intensity of SV hydrocyclone are reduced in different degrees compared with conventional hydrocyclone, and the reduction becomes more obvious with the increase of vane width. In the case of a vane width of 0.04D, the underflow recovery rate of 5µm and 10µm fine particles was reduced by 16.2% and 15.7%. The selection of spiral vanes with small widths is beneficial to improve the separation accuracy of fine particles and reduce the cut particle size. [ABSTRACT FROM AUTHOR]

This study established a full-scale hybrid water treatment system combining a hydrocyclone, coagulation, flocculation, and dissolved air flotation unit (HCFD) and evaluated its performance in treating anthropogenically impacted lake water. The HCFD system offered the stable and efficient treatment of fluctuating influent loadings, meeting most of the highest water reclamation quality criteria except for that of organic matter. Adsorption was subsequently examined as a post-treatment process for the HCFD effluent, which has not been examined in many previous studies. As the adsorbent for the post-treatment, pine bark, a locally available agricultural waste feedstock, was modified using H2O2 to maximize its adsorption capacity. The surface modification increased its adsorption capacity for organic matter by 53–112%. The HCFD system in conjunction with the synthesized adsorbent thus demonstrated the ability to meet the highest standards for all water quality parameters, highlighting their synergistic potential for enhancement of water treatment. Liquid chromatography–organic carbon detection and Fourier transform infrared analysis were then employed to determine the mechanisms involved in the removal of specific contaminants using the HCFD system and post-adsorption unit. While the HCFD system successfully eliminated particulate and colloidal matter (e.g., phosphorous and biopolymers with a high molecular weight) using centrifugal and floating separation with the aid of two complementary polymers, the post-adsorption unit effectively adsorbed small-sized dissolved substances (e.g., low molecular weight acids and building blocks) via surface functional groups (–CH, –OH, –CH2, C=O, C=C, and C=O) using van der Waals forces, hydrogen bonding, and π–π or n–π interactions. [ABSTRACT FROM AUTHOR]

Cyclones are pivotal in mechanical process engineering and crucial in the complex field of separation technology. Their robustness and compact spatial requirements render them universally applicable and versatile across various industrial domains. Depending on the utilized fluid and field of application, both gas-based cyclones and hydrocyclones (HCs) are well established. Regarding HC design, enduring elongated flat cones have seen minimal alterations in shape and structure since their introduction over more than a hundred years ago. Experimental investigations regarding unconventional cone designs within scientific studies remain the exception. Therefore, this study focuses on alternative geometric configurations of the separation chambers and highlights their impact on separation and energy efficiency. To achieve this objective, different geometric shapes are investigated and retrofitted into HCs. The geometric foundation is derived from upcycled glass bottles. The repurposed bottles with a volume of 750 mL are used in conjunction with an inlet part, following the established Rietema design. Experimental tests are conducted with dilute phase separation, using 0.1–200 µm test particles in water. Comparisons between a bottle-based HC and a conventional Rietema design were conducted, establishing a benchmark against the standard. The findings revealed a noticeable correlation between separation efficiency and cone geometry. Conical designs demonstrated enhanced separation, particularly at lower volume flows. At the highest volume flow of 75 L min−1, the best performing bottle cyclones showed separation efficiencies of 78.5%, 78.4% and 77.9% and therefore are in a competitive range with 78.0% efficiency, achieved using the commercial Rietema design. Minimal disparities in cut sizes were observed in terms of separation grade efficiency among the models tested. Variations in separation efficiency and fractional efficiency curves indicated nuanced differences in classification efficiency.

Due to the scarcity of phosphorus as a strategic resource, there is a growing trend to extract and refine low-grade phosphate ore using hydrocyclones. This study focuses on purifying low-grade phosphate ore using a hydrocyclone, with experiments conducted to obtain data on inlet velocity, mass flow rate, and pressure of inlet and outlet. These measurements assess pressure drop, separation efficiency and accuracy, thereby validating the numerical simulation outcomes. The Mixture and RSM models are used to simulate and analyze the hydrocyclone's internal multiphase flow field and performance of separation at varying inlet velocities. Findings show that an inlet velocity ranging from 6 to 7 m/s results in over 90% separation efficiency, around 90% separation accuracy, and low energy expenditure. These research findings provide theoretical guidance for low-grade phosphate ore separation and purification using hydrocyclones.

The reliability of drip irrigation systems depends on the quality of water purification of the water sources used. The degree of its purification is a particularly important factor affecting the performance of all components of irrigation systems, including droppers. The purpose of the study was to assess the applicability of a hydrocyclone with adjustable parameters to improve the quality of water purification in drip irrigation systems. The research was carried out using the method of comparative tests of various configurations of sections of the inlet pipe of the hydrocyclone, considering changes in their angle of inclination along the vertical plane and changes in the depth of immersion of the drain pipe. By changing the configuration of the inlet pipe of the hydrocyclone, the angle of deviation along the vertical (θ°) and horizontal (φ°) planes, as well as the depth of immersion of the drain pipe (ac), the effect on the distribution of the flow rates between the discharge holes required for the quality of cleaning has been established. It has been found that the greatest clarification of water is provided with the semicircular shape of the inlet pipe, with the inclination of the inlet pipe along the vertical plane θ° = 20... 40, with the immersion of the drain pipe to the interface plane of the cylindrical and conical parts of the hydrocyclone. [ABSTRACT FROM AUTHOR]

A pilot hydrocyclone plant was used to concentrate medium-grade celestine ore (67% celestine) from the Montevive deposit in Granada (Spain) by using a dense media concentration (DMS) process. To optimize the concentration process, several types of heavy minerals (coarse, fine C40 ferrosilicon and/or magnetite) were used to prepare a dense media with a constant density of 3.0 kg/L. Then, the dense media (loaded with run-of-mine celestine mineral) was fed into the hydrocyclone system. The mineral was then separated into two streams, the first containing the mineral fractions that float (over stream) and the second containing fractions that sink (under stream) in the dense media. Next, the heavy minerals (ferrosilicon and/or magnetite) were recovered from the dense media using magnetic separation. The celestine mineral recovered from each stream was divided into two fractions with particles size above or below 250 μm to study the effect of the mineral particle size on the separation process. Their mineral composition was quantified by X-ray diffraction (XRD) using the Rietveld method. The celestine is preferentially concentrated in the under stream in the mineral fraction with particles larger than 250 μm (up to 90% celestine). The optimum results (highest % of celestine) were obtained after desliming and using the ferrosilicon C40 medium, which has the smallest particle size (<40 μm) of all media used. The results of this study show that medium-grade celestine mineral accumulated in the mine tailings can be efficiently concentrated using a DMS process, which could help in making mine operations more sustainable and eco-friendlier. [ABSTRACT FROM AUTHOR]

The problem of judicious selection of hydrocyclone design parameters to minimize energy consumption while ensuring the required suspension separation indicators with a prescribed volume output was studied. Theoretical analysis showed that energy consumption would be minimal if the inlet pipe diameter is 0.366 part of the diameter of the cylindrical part of the hydrocyclone and the diameter of the top drain-pipe, which can be determined by an equation depending on the angle of the tapering part of the hydrocyclone and on the ratio of the diameter of the separation boundary grain to the diameter of the tapering part of the hydrocyclone. The dispersed phase to dispersion medium density ratio does not affect energy consumption. [ABSTRACT FROM AUTHOR]

The Seridó region, located in northeastern Brazil, in the states of Paraíba and Rio Grande do Norte, is known for its vast reserves of kaolin from pegmatites. Small companies mine and process ore. However, these operations are precarious, lacking mining planning and processing studies. Consequently, the recovery rates are only 25%, and mining accidents happen. Within a Ministry of Science and Technology work project named Associated Entities, the Centre for Mineral Technology and the Federal University of Campina Grande carried out integrated research, technology and innovation actions to add value to the mineral production chain in the Seridó region. After elaborating on a working plan, the partners collected information on the area, which they used to construct geological maps and computerized mine models. In addition, a kaolin processing plant with a hydrocyclone, aiming to increase the ore's recovery, was studied. This project results were two pit design scenarios with distinct geometric characteristics for the mine planning stage. The first scenario presented better results than the second, with a higher ore tonnage recovery and a lower waste/ore ratio. In the processing stage, the hydrocyclone tested plant led to a concentrate with high kaolinite percentages. The mining and processing project showed the possibility of extracting and processing the kaolin ore in a safer and more economically viable way for small producers. [ABSTRACT FROM AUTHOR]

Several optimization studies were made to increase metal recovery and reduce operational costs of the concentrator in Siirt Madenköy copper mine. In consequence of these studies, effects of the changes in operating parameters, cost and plant recovery will be examined at this article. In this article, we will discuss two important revision studies, which are (i) replacement of 500 mm hydrocyclone set used in ball mills with 350 mm of hydrocyclone set, (ii) replacing the present Ball Mill with a SAG mill. Correspondingly elimination of the crushing and screening plant, (iii) increasing the scavenger cells from 4 to 6 by the addition of 2 more cells. In consequence with this feeding the middling tail to the increased scavenger cells which was treated as a part of final tail before this change. We will examine the effect of all these changes to the final recovery, concentrate grade and final cost. [ABSTRACT FROM AUTHOR]

The particle motion behavior in hydrocyclones has received increasing attention, but the particle circulation flow has received relatively limited attention. In this paper, the particle circulation flow is regulated by changing the secondary-cylindrical section diameter to optimize the separation effect. The effects of secondary-cylindrical section diameters on flow field characteristics and separation performance are explored using the two-fluid model (TFM). The findings demonstrate that particle circulation flows are ubiquitous in the secondary-cylindrical hydrocyclone and are induced by the axial velocity wave zone. The increase in the secondary-cylindrical section diameter intensifies the coarse particle circulation and aggrandizes the coarse particle's aggregation degree and aggregation region, leading to an increment in cut size. The circulation flow component can be regulated by adjusting the secondary-cylindrical section, thus improving the classification effect. An appropriate diameter of the secondary-cylindrical section facilitates improved particle circulation, strengthening the separation sharpness. [ABSTRACT FROM AUTHOR]

Hydrocyclone is the basic application equipment of purification treatment in the process of oil and gas field exploitation. With the continuous development of the oil field, the actual exploitation environment of the oil field is getting worse and worse, and the requirements for the equipment treatment efficiency of hydrocyclone are getting higher and higher. In order to improve the treatment efficiency of hydrocyclones and meet the actual treatment requirements, several main hydrocyclones in oil field purification treatment were introduced, and their separation principles and research progress were analyzed and summarized in detail. According to the different types of hydrocyclones introduced, a systematic summary and prospect were made, and the research direction of hydrocyclones in the future was pointed out. [ABSTRACT FROM AUTHOR]

Ore resources in the mining process form a large number of unmanageable tailings, mostly inhalable fine mineral particles, into the environment will cause serious pollution, and recycling is a precious resource. The cyclone classification provides the possibility for the recovery and exploitation of fine particles, but the recovery and utilization rate of conventional cyclone separation is seriously low, and the performance urgently should be optimized. In the present study, a new type of volute feed was proposed to strengthen the classification and recovery process of fine mineral particles. Combined with numerical simulation and experimental research, the effects of various structural parameters and operating parameters on the flow field distribution, particle motion, and classification performance were systematically examined. The obtained results reveal that the new volute feed structure can effectively reduce the internal turbulence and improve the flow field stability and particle classification efficiency. Compared with the traditional hydrocyclone, the classification efficiency of fine particles with new feed structure increases by 10–18%. Increasing underflow diameter and feed pressure and reducing overflow diameter and feed concentration are also beneficial to lessening classification particle size and enhancing classification performance. The currently achieved outcomes can provide valuable guidelines for further development of novel hydrocyclones. [ABSTRACT FROM AUTHOR]

An attempt has been made in this work to experimentally investigate the water split behavior of hydrocyclones for extracting the relevant features that are characteristic of hydrocyclone design conditions only. The experimental findings demonstrated that at high feed flowrates, the water split of the hydrocyclone attains a consistent value, referred to here as the stable split value, because of a fully developed and steady vortical flow through the hydrocyclone. These stable split values were shown to be characteristic of the hydrocyclone design conditions. An empirical model developed in the study considering the key hydrocyclone design variables could predict the stable split values with a validation R2 of 0.98 and 0.96 for the training and testing data, respectively. It is believed that such a design-dependent parametric representation of the water split behavior can be significantly useful for hydrocyclone design comparison and selection which has not been reported in the literature so far. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydrocyclones can be used to concentrate the entrained sands in sewage and alleviate the clogging and erosion of the drainage network, but in practical application, there are problems such as low concentrations of underflow and a high content of fine particles, which cause a significant load on the subsequent sand dewatering and recycling. This paper designs five spigot structures of hydrocyclones and investigates the separation performance by numerical simulation, aiming to improve the applicability of hydrocyclones in the sewage treatment process by optimizing the spigot structure. The research results show that a large cone spigot delays the external downward swirling flow and reduces fine particle content in the underflow, but its effective separation space is reduced, and the turbulence in the cone section area is more intensive, which influences the separation accuracy. An elongated spigot has a reduced underflow water distribution; fine particles are more enriched in the internal swirling flow, and the underflow recoveries of 1 μm and 5 μm particles drop by 2.34% and 2.31%. The spigot structure affects the downward fluid and air intake states; complicated spigot structures contribute to increasing the resistance of particle discharge through underflow, alleviating fine particle misplacement.