Hydrocyclone Classification Research Articles

Performance comparison of laboratory scale air classifier and hydrocyclone at the same target size

The research aimed at comparing the performances of two common centrifugal type classifiers, air classifier and hydrocyclone, operated dry and wet respectively. The reason for starting the study is the possible shifting to dry processing in the future as the water has limited availability. Such comprehensive research has not been undertaken in the literature although individual assessments were completed. Within the scope, copper ore, gold ore and magnetite-calcite blends were chosen as these applications are common globally. The research commenced with the experimental tests via laboratory scale air classifier and hydrocyclone. Afterwards, size analyses and component measurements (via XRF, MLA, fire assay) were undertaken. The data was initially used in mass balancing of the experimental data to adjust the flow rates alongside with assays then Tromp curves were plotted to determine cut size, sharpness of cut, bypass parameters. Comparison of the two classifiers were completed for the same overflow target sizes. Throughout the assessments, the magnitudes of the Tromp curve parameters for the overall classification and component-based results were compared. As a result, air classifier may be alternative to hydrocyclone classification since less bypass, higher sharpness values were obtained. This study provides insights on choosing the dry or wet classification.

Experimental and numerical study of the effect of particle size distribution on hydrocyclone classification

Classification by particle size using hydrocyclones is a fundamental step in various industries, yet the influence of material properties remains an area of limited understanding. This paper presents a comprehensive experimental and numerical investigation to illuminate the complex relationship between the feed particle size distribution (PSD) and the classification process. The feed PSD is characterised by two crucial parameters: the median size (d50f) and the distribution coefficient (σJ), derived from Johnson’s SB function. The results reveal non-monotonic variations in cut size and curve slope during physical tests where the two parameters are not separated. With one parameter held constant in numerical tests, an increase in d50f generally leads to a decrease in pressure drop but an increase in water split, while σJ exhibits an opposite trend. The interplay between the two parameters and their effects on cut size and cut sharpness is intricate, primarily determined by the characteristics of the flow field and the relative sizes of the cut size and d50f in the feed. These findings underscore the critical role of feed material properties in operating hydrocyclones for fine particle classification.

Enhancing classification and recovery of barite from waste drilling fluid by inlet particle arranging of hydrocyclone

Improper disposal of waste drilling fluid will cause severe pollution of the ecological environment and massive loss of resources such as barite. Based on the principle of arranging particle to enhance the hydrocyclone classification, a triple hydrocyclone pre-sequencing grading system for treating waste drilling fluid was designed in this paper. The influence of the swirl particle arranger and its cone angle on the classification and recovery characteristics of barite particles in waste drilling fluid was studied. The results showed that under experimental conditions, compared with the triple hydrocyclone grading system without the particle arranger, the recovery rate of barite increases by 5.7 % to 75.0 % after setting a cylindrical arranger in front of hydrocyclone. As the arranger's cone angle increases, the device's classification performance increases first and then decreases. The classification performance was best when the arranger cone angle was 6°. At this time, the solid content of drilling cuttings in the recycled purified fluid was only 27.1 g/L. This was 47.9 % lower than the inlet. And the recovery rate of barite reached 78.9 %. This technology can realize the deep removal of drilling cuttings, the efficient recovery of barite and the recycling of betonies.

CFD study on the influences of size distribution and density of magnetite ore particles on hydrocyclone classification process

Due to the presence of gangue minerals in iron ore, the feed of hydrocyclone in the grinding circuit is a mixture of particles with different densities and sizes. In this study, numerical experiments are performed to investigate the classification characteristics of magnetite ore particles. A significant difference in recovery to underflow of intermediate-sized particles is found due to density effect. By increasing the feed d0.5, the cut size, Ep value, solid concentration and yield of underflow present an increasing trend. Density effect coefficient is proposed and its extreme values are obtained for intermediate-sized particles. Q/M ratio has smaller influences on classification than feed d0.5. The air core diameter, turbulence intensity, equilibrium radius and particle trajectory are analyzed to reveal the migration mechanism of the magnetite and gangue particles under different feed d0.5 and Q/M ratios. This work clarifies the intrinsic classification characteristic of magnetite ore particles.

Performance analysis of the beneficiation process of bauxite from the Juruti Mine. Industrial sampling and performance evaluation

Sampling campaigns were conducted at the industrial bauxite wash circuit of the Juruti Bauxite Mine in Pará, Brazil. The beneficiation circuit consisted of crushing, scrubber washing, wet screening, hydrocyclone classification, and fltration. Considering laboratory processing of samples and statistical analyses of historical operation databases, mass balances were obtained. Integrated analyses of historical databases, mass balances and operating parameters enabled the calculation of performance indices, which constitute the basis for the identification and hierarchy of the bottlenecks in terms of washability efficiency; that is, removal of the fraction below 0.037 mm. Typically, the focus of bauxite ore concentration in the Amazon region is the removal of the 0.037 mm fraction in the concentrate streams via disaggregation and mud washing. Consolidated mass balances indicated consistent values based on the size of the sample particles and percentage of solids, as well as the values obtained from the integrated information systems of the plant; this consistency indicated the stability and representativeness of the process conditions during the sampling campaigns. The base case of the Juruti plant operation, from which the performance indices that allowed the quantification of the efficiency of each process step was calculated, was obtained as a result.

The effects of solid shear stress and wall roughness on the simulation of cylindrical hydrocyclone classification

Reasonable numerical conditions are critical for the precision and accuracy of the numerical consequences of hydrocyclones. In this paper, the effects of resistance coefficient, wall roughness, and friction packing limit on particle velocity and distribution as well as the separation behaviors were studied in a cylindrical hydrocyclone using the two-fluid model. The results show that the friction packing limit and wall roughness can significantly influence the numerical results, whereas the effect of the resistance coefficient is negligible. As the friction packing limit increases from 0.4 to 0.55, the cut size gradually decreases with improving separation sharpness, and it reaches the minimum when the friction parking limit is 0.5. The wall roughness monotonously increases the cut size and reduces the separation sharpness. Simulation results were also compared with experimental data, and a reasonable prediction can be obtained with resistance coefficient, friction packing limit, and wall roughness height of 0.95, 0.5, and 50 μm, respectively.

High Concentration Fine Particle Separation Performance in Hydrocyclones

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.

The Performance Prediction Model of W-Shaped Hydrocyclone Based on Experimental Research

Fine particles misclassification in the underflow (UF) of grinding-classification hydrocyclones might result in ore over-grinding, leading to both reduced ball mill throughput and metal recovery. In the current research, a W-shaped hydrocyclone is proposed, to efficiently decrease the misclassification of fine particles in UF. The effects of the following parameters (including cross-effects) on W-shaped hydrocyclone classification performance were studied experimentally—inlet pressure, apex diameter, and vortex finder insertion depth and diameter. A mathematical model on the basis of the response surface method was established for the prediction of W-shaped hydrocyclone separation performance. The significance of the effects of the factors on the fine particle content in UF decreased in the following order—vortex finder diameter > inlet pressure > vortex finder insertion depth > apex diameter. The significance of influences of different factors on quality effectively decreased in the following order—inlet pressure > vortex finder insertion depth > vortex finder diameter > apex diameter. The significance of factor effects on the quantity efficiency decreased in the following order—inlet pressure > vortex finder insertion depth > apex diameter > vortex finder diameter. All influence factors were considered to obtain the optimal parameter configuration—an apex diameter of 0.14 D, a vortex finder diameter of 0.31 D, an insertion depth of 1.87 D, and an inlet pressure of 0.18 MPa. The corresponding optimal result was a −25 μm particle content (C−25) in UF of 11.92%, a quality efficiency of 42.48%, and a quantity efficiency of 98.99%.

Beneficiation of White Kaolinitic Sandstone to Produce Kaolin Concentrate from Wadi Siq-Rakyia Area in Wadi Araba, Jordan

Kaolinitic sandstone samples of Lower Cretaceous from Wadi Siq-Rakyia area in Wadi Araba/south of Jordan were studied and assessed as a source of Kaolin. Three channel samples and a composite bulk sample were studied for their mineralogical, geochemical, and grain size distribution analysis. The aim of this research work was to achieve kaolin concentration by examining the best-suited and cost-effective processing method(s) with appropriate product recovery. Following the initial sample characterisation at “bench scale”, a pilot study was performed on the bulk sandstone sample. Kaolin was accumulated in the fine size fraction (−125 μm) after agitating and wet screening of the sample. The −125 μm size fraction sample was used to produce kaolin concentrate. Hydrocyclone classification was applied in the pilot study for this purpose. The mass flowrate of the feeds and the products in the hydrocyclones was calculated for the bulk sample as well as the amount of water required operating the process. A kaolin-enriched product was produced following the use of hydrocyclones. A kaolin concentrate at a grade of 71% and a recovery of 78% was produced which could be used in the ceramic industry for tableware and sanitaryware.

Centrifugal classification of pseudo-boehmite by mini-hydrocyclone in continuous-carbonation preparation process

Pseudo-boehmite (PB) is often used as a precursor for hydrotreating catalyst support (γ-Al2O3) in the petroleum refining process. Recently, continuous-carbonation process was proposed to prepare PB in order to meet the increasing demand for macroporous γ-Al2O3, but the highly dispersed particle size of PB in this process limited its development. To obtain the PB with monodispersed particle size, a 10mm mini-hydrocyclone was designed by 3D printing technology and used to the classification for PB. Then a high-performance zone for classification with Re of 4000–5000 was obtained. The volume ratio of particles (>10μm) was increased from 56.3% to 83.5% at a split ratio of 15%, and the mean particle size was increased from 12.9μm to 45.7μm, which indicated that the highly dispersed particle size could be efficiently concentrated into monodispersed one by hydrocyclone classification. Under optimal operating conditions (Re of 4360 and Rf of 15%), the hydrocyclone was unprecedentedly applied to the continuous-carbonation preparation process of PB, and the volume ratio of particles (>10μm) was significantly increased from 53.1% to 75.6% in the pilot test. This finding contributed to optimize continuous-carbonation process and improve product performance.

Hydrocyclone classification control

An overview of the classification systems in hydrocyclones in the copper ore enrichment departments at KGHM Polska Miedź SA was presented. In recent years, IMN has been conducting an investment - replacing hydrocyclones with modern HC hydrocyclone solutions - manufactured by ZAM Kęty and IMN. The results of implementing modern hydrocyclones are presented. The important issue is to define relation between values of pressure and/or hydrocyclone feed density and cut point achieved in these conditions for chosen classification node By disposing this relation, implemented to classification monitoring system is possible to maintain cut point value within the range ± 5 % of assumed value by preserving acceptable feed variation in industrial conditions: - change of suspension density ± 20 % in ratio to assumed value, - change of feed particle size d80 ± 15 % in ratio to assumed value.

Improvement of the filtration characteristics of calcite slurry by hydrocyclone classification

Hydrocyclones are used in the classification of solids for instance in the mining and minerals processing industries for modifying the particle size distribution of solids, as well as for ore concentration purposes. Improvement in the filtration properties of the slurry is usually achieved as a result of the classification process when only the underflow is evaluated, owing to the coarse and narrow particle size distribution. However, overall comparisons of the filtration properties incorporating filtration of both the underflow and overflow streams have not been discussed a lot in the literature. The objective of this study is to investigate hydrocyclone classification of a calcite slurry, to evaluate the resulting pressure filtration properties of the underflow and overflow streams, and to compare the required total filtration areas for a constant solids production capacity. The results show that the average specific cake resistance depended primarily on the fine particle content of the slurry, and therefore the Kozeny-Carman equation was not suitable for the prediction of the specific cake resistance. The specific resistances of feed and underflow filter cakes were underestimated consistently. Wide particle size distribution was one of the most apparent factors reducing cake porosity. The main outcome of the comparison of the required filtration areas was that a low specific cake resistance and high solids concentration of the underflow caused the total area requirement to decrease almost in all cases, compared to the area required for the filtration of the feed slurry. Moreover, as high as 99% reduction in the total filtration area, compared to the feed slurry, could be achieved by filtering only the underflow streams, omitting the dewatering of the overflow streams. In the light of the promising results of the study, the incorporation of a classification step prior to filtration should be investigated further, e.g. in tailings treatment applications.

Efficient separation of hazardous trace metals and improvement of the filtration properties of green liquor dregs by a hydrocyclone

Abstract The treatment of green liquor dregs (GLD), the main inorganic solid residues of kraft pulp mills, is a major concern in the industrial scale. In this study, the effect of hydrocyclone classification on the filtration properties of GLD and the separation of hazardous trace metals, such as Cd, Ni, Pb and Zn, rare earth elements, and other trace metals was investigated. The experiments were designed to find the influence of parameters such as the overflow to the underflow outlet diameter ratio and inlet pressure on the separation efficiency of a hydrocyclone. The results showed that a lower total filtration area was required for the separation of underflow and overflow fractions than for the original GLD sludge. Also, hazardous trace metals were effectively separated into finer overflow fractions, enhancing the possibilities to utilize the purified underflows e.g. in fertilizers and soil amendment. By using the diameter ratio of 3.70 and the inlet pressure of 1 bar, 90.1 wt-% of Cd, 70.1 wt-% of Ni and 91.4 wt-% of Zn were separated into the overflow, collecting 30 wt-% of the dregs in this fraction. The concentrations of rare earth elements (REEs) in the underflow solids were lower than the ones in the original sludge. Unlike the trace metals and REEs, Ca was accumulated in coarser particles that were separated by underflow fractions. Therefore, a majority of the dregs, enriched by Ca, was separated by underflow fractions. The possibility of categorizing the underflow fractions in CE-marked fertilizing products was also studied.

Expressing Efficiency as a Function of Key Performance Control Parameters: A Case Study of Hydrocyclone Unit Process at Josay Goldfields Limited, Tarkwa, Ghana

Optimization of gold liberation is a function of hydrocyclone (cyclone) classi-fication efficiency with regard to a given target of 80% passing 75 μm at Josay Goldfields Limited. Key performance parameters that control the classification efficiency are hydrocyclone feed density, hydrocyclone feed pressure and throughput under fairly constant grinding process conditions. The hydrocyclone feed density related linearly to overflow product of percentage passing 75 μm and showed statistical linearity at even 1% critical level of significance. The paper provides a relation between cyclone feed density and cyclone overflow product size fraction as a function of cyclone efficiency. Gradient of the relation establishes the standard unit of performance which depicts the classification efficiency as percentage passing 75 μm per percentage solids of cyclone feed density. This measurement provides a timely corrective action of key performance control parameters. The selected seven days samples space used in the assessment was due to the effect of a daily production deficiency on the overall profit margin of Josay Goldfields as company.

Automated control of hydrocyclone classification

Automated control of hydrocyclone classification

Effect of acid treatment on the chemical composition and the structure of Egyptian diatomite

In this study Egyptian diatomaceous earth from Kasr El-Sagha locality in El Fayium province, Egypt was used. A highly purified diatomite has been prepared successfully by using a two stage process. In the first stage, samples of Egyptian diatomite were subjected to several mechanical techniques (attrition scrubbing and hydrocyclone classification) to remove most of the accompanied gangue minerals like inorganic carbonate, silica sand, and clay. The fraction with a particle size of −45μm was then submitted to a thermo-chemical treatment. This second stage started with a calcination of the diatomite samples at 1023K for 1h. Three modified forms of diatomite were then prepared by hot acidification of the calcined diatomite samples with aqua regia (5M HCl+5M HNO3), 5M sulphuric acid or 5M hydrochloric acid. The refined products were characterized by X-ray diffraction, X-ray fluorescence, low temperature nitrogen adsorption, mercury intrusion and scanning electron microscopy. Silica materials with high purity (>96wt.% SiO2) and an accessible and interconnected mesopore structure could be obtained. Additionally, all samples displayed a large amount of macropores of about 1μm diameter and a broad distribution of larger interstitial macropores. The treatment with hydrochloric acid led to products with a specific surface area between 120 and 150m2g−1 and 63wt.% of amorphous phase.

Beneficiation of Low Grade Kaolin by High Shear Agitation with Dispersant (HSD) Pre-Treatment for High Yield and Improved Fired Colour

Crude kaolin contains various amounts of discolouring elements such as anatase (TiO2), mica and iron oxide (Fe2O3), which give low brightness and are detrimental in use. In addition, the anatase (titaniferrous) and mica can also contain iron contaminants. Beneficiation of two crude low grade china clays, marked as KY and SR, was attempted through imitating existing industrial practice of levigation and hydrocyclone classification, and through an innovative technique of high shear agitation with dispersant (HSD) pre-treatment. HSD treated clays were subjected to impurity removal by sieving, demagnetizing and coarse/heavy impurity removal by sedimentation under gravity techniques. The results in terms of yield of clay (% on feed basis), grade of clay (kaolinite%) and effect of purified clays on the whiteness of porcelain were compared. It was found that by use of HSD pre-treatment, SR dump clay could be purified to contain 90.7% kaolinite and 0.75% free silica with a striking yield of 62.32% as compared to 88.90% kaolinite, 3.34% free silica and 30.2% only as yield by levigation and hydrocyclone. The KY dump clay was purified to contain 85.51% kaolinite and only 5.57% free silica with 44.3% yield by HSD pre-treatment as compared to 72.29% kaolinite, 16.29% free silica and 30.4% only as the yield by levigation and hydrocyclone classification. The kaolinite enrichment and removal of free silica to a major extent and chromophore impurities (although to a minor extent) in these dump clays after beneficiation rendered them suitable for polished vitrified porcelain tiles application as far as the development of white fired colour in the tiles body is concerned.

Simulation of a ball mill operating with a low ball charge level and a balanced ball size distribution

The optimization of industrial grinding circuits has been successfully performed using mathematical models that describe the industrial scale data from breakage parameters determined in laboratory grinding tests. The test material studied here is a gold ore ground in a closed ball mill circuit with hydrocyclone classification. Several sampling campaigns were carried out aiming to produce mass balances and provide material for laboratory tests. The parameters determined in the laboratory tests were used to predict, by simulation, the circuit behavior with a low ball charge level and a balanced ball size distribution.

Optimization of hydrocyclone classification by on-line detection of coarse material in the overflow stream

This paper presents a new instrument for real-time detection of excessively coarse material in the overflow pipes of individual hydrocyclones using a non-invasive acoustic measurement technique.The hydrocyclone is an important device used in mineral processing beneficiation circuits for classification of mineral slurries by particle size. It separates a single input stream into two output streams; an underflow of coarse particles that undergo additional grinding for further size reduction, and an overflow stream of finer particles that typically goes directly into a flotation circuit for recovery of the desired mineral. However the hydrocyclone is a major piece of equipment in the beneficiation process that has no instrumentation for directly measuring its performance. The parameters currently measured – inlet pressure, feed flow rate, feed flow density – are common to the entire hydrocyclone cluster which typically has three to twelve hydrocyclones. Thus no information is available to detect individual hydrocyclones that are operating poorly.The system described in this paper detects the presence of unwanted excessively coarse material in the overflow stream of a hydrocyclone using sensors mounted to the exterior pipe surface. It provides real-time monitoring, trending and alarming of the coarse material level. This enables operators to identify poorly performing hydrocyclones, and enables corrective action to reduce or eliminate the coarse material discharge.Improving the classification efficiency of individual hydrocyclones will improve the overall classification efficiency of a hydrocyclone cluster. This leads to less variation in the particle size distribution and slurry density in the flotation feed, which will in turn improve overall mineral recovery. The reduction of unwanted coarse material in the flotation feed reduces the accumulation of that material in flotation cells. This can lead to equipment damage, and unplanned shutdowns due to events such as blocked dart valves.

Effect of particle shape on hydrocyclone classification

Influence of particle shape on hydrocyclone classification was investigated. Classification tests using hydrocyclone and cyclosizer showed that coarse fractions of plate-like particles such as PTFE and glass flake used here were not necessarily recovered as underflow product, especially at relatively high inlet velocity. Settling velocity of the glass flake particles in centrifugal field was estimated using a centrifugal particle size analyzer, and it was revealed that differences in settling velocity between coarse and fine glass flake particles became smaller with increases in angular velocity. Moreover, settling test of glass plate in water or glycerin solution was conducted to know relationship between particle Reynolds number (Re) and settling velocity of the plate. At smaller Re condition, the glass plate settled straight and stably, and larger plate settled faster than smaller plate. However, oscillating motion of the plate occurred in the region of high Re, and settling velocities of the large plate became smaller than that of the small plate in such conditions. Drag coefficient (C) calculated based on the settling velocity of the glass plate is similar to that of glass spheres below Re of about 50, above which it became larger than that of glass sphere. Approximation formula of correlaton between Re and C suggests that the influence of the Re on C can be neglected in the region of high Re, and C increases with increases in the ratio of the particle diameter to thickness (D/T).The decrease of the difference in settling velocity recognized in the centrifugal settling test and the effect of the particle shape (D/T) on C at high Re region are considered to be able to affect the hydrocyclone classification. The misplacement of coarse plate-like particles in the hydrocyclone and cyclosizer tests could be ascribed to the particle shape effects.