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By C. R. Mambote

One of the processes developed for vanadium recovery from the fly ash of crude oil is through acid leaching. In the process, iron is one of the impurities that should be removed before vanadium precipitation, due to the fact that iron tends to co-precipitate with vanadium. The mechanism of iron precipitation is understood in terms of ferric hydrolysis, followed by the dimerization and subsequent polymerization of the crystalline iron compound. In order to develop a new approach for the fly ash processing, in the present paper the precipitation of iron from the liquor after the leaching process was studied with addition of NaOH or NH4OH in the presence of H2O2 or Na2C2O4 at 80°C. The objective was to investigate the feasibility of the selective precipitation which could be applied to vanadium and nickel recovery from the fly ash. The experimental results show the difficulties of removing iron by precipitation without co-precipitating nickel and vanadium.

Jan 1, 2014

By Hermann Wotruba, Günther Petzold, Fabian Riedel

"Increased mechanisation in underground stoping operations results in higher waste percentages in the run of mine. A new method of reducing waste is optical sorting. Optical sorters have low maintenance costs and can be installed underground. Rejected waste can be backfilled directly without having to be hoisted, therefore increasing the shaft capacity for a more valuable product.Pre-Concentration by Optical SortingA series of tests with an optical sorter at the laboratories of the Mineral Processing Department of the RWTH Aachen have shown that it is technically possible to sort almost any kind of ROM which has even slight differences in colour (Platinum Reef, Gold Reef, Kimberlites, Industrial Minerals, Aggregates, Coal, etc.).By employing optical sorters prior to conventional sorting plants, it is possible to reduce the amount of waste to be processed. Figure one shows test results of ore which is quite similar in colour to the waste (grey). With increasing waste in the feed, the recovery decreases according to the graph. In figure two, the colour ratio parameter of the sorter was changed with a similar waste percentage in the feed. With increasing loss of ore, a cleaner product can be achieved. Before designing a sorting plant, throughput tests are carried out. Throughputs vary depending on the size range. Sorters have a limit of about 250mm top size. In this upper size range, throughputs of 150t/h can be achieved."

Jan 1, 2003

By Graeme J. Jameson

In conventional flotation machines, the recovery is strongly related to particle size. As particle size increases, the recovery also increases, reaching a maximum in the range 20 to 120µm. Beyond this range however, the recovery declines quite quickly. The reason for the decline in recovery observed with coarse particles can be traced to the effect of turbulence. Bubbles trapped in turbulent eddies rotate rapidly, and when the centrifugal force on a particle exceeds the retaining forces due to surface tension, the particle detaches. Since the centrifugal force varies as the cube of the diameter of the particle, and the attachment force varies simply as the diameter, being proportional to the length of the contact line, it is clear that detachment forces will predominate as the particle size increases. The corollary is that the recovery of coarse particles can be improved if the level of the turbulence in the cell can be reduced to a minimum. In this paper, a new type of flotation machine will be described, in which the particles to be floated are suspended in a fluidized bed. An up flow of fluidizing water is provided, by recycling liquid from the top of the cell. The recycle stream is aerated in a high-energy device that disperses the air into fine bubbles that capture the fines and ultrafines. Results are presented for several minerals and coarse coal. Keyword: fluidized bed flotation

Sep 1, 2012

By Hiroshi Sasaki, Herman D. Mendoza

"The surface-chemical property of nickel slag fiber was modified in aqueous media in order to act as an active and efficient collector of colloidal amorphous silica from geothermal effluent. Colloidal amorphous silica (0.05 µm) from geothermal wastewater causes operational and ecological problems. It clogs geothermal pipes and waterways, and when disposed to the environment poses hazardous effects on both the flora and fauna ecology. Because colloidal amorphous silica is extremely fine and remains in suspension in aqueous media, conventional solid/liquid processes to remove colloidal silica from its bulk liquid are rendered ineffective.A rapid separation technique is then developed to remove effectively amorphous colloidal silica from its bulk liquid by attaching the extremely fine particles of silica onto a nickel slag fiber coated with magnesium hydroxide, Mg(OH)2. The nickel slag fiber has the following characteristics: a high surface area and predominantly possesses negative charge in aqueous media with an iso-electric point at pH ~2.5. When soaked and saturated with Mg(OH)2 solution, the surface of the nickel slag fiber becomes coated with fine and compacted Mg(OH)2 precipitates. This modifies the surface- chemical property of nickel slag fiber transforming the negatively charged surface into a positively charged surface in aqueous media with an iso-electric point of around pH 11.8, which corresponds to the iso-electric point of Mg(OH)2. When geothermal effluent containing negatively charged colloidal amorphous silica particles (i.e.p. of silica is pH 2) is passed through a column-bed packed with surface-chemically modified nickel slag fibers under natural pH conditions, the colloidal amorphous silica particles are recovered by attachment onto the surface of the surface- modified nickel slag fiber. The recovery of colloidal amorphous silica by attachment is 97-99%, resulting in the production of a relatively clean and silica free output. Aluminum hydroxide, Al(OH)3, was also used to modify the surface –chemical property of the nickel slag fiber. In the same way, it also exhibited a positive response with the collection of colloidal amorphous silica from its bulk liquid, but yielding a lower recovery of 90%. This may be attributed to the lower surface potential and iso-electric point of pH 9.3 for Al(OH)3. The separation process was evaluated and analysed using existing potential energy theories. Figure 1 shows a micrograph of the surface of an unmodified and the Al(OH)3 –modified surface of nickel slag fiber."

Jan 1, 2003

By M. Ito

The authors have developed the RETAC jig (a modified TACUB jig) and have reported that the RETAC jig can separate relatively low density particles such as plastics. To further improve the separation ability, a hybrid jig (a RETAC jig with an air bubbler under the particle bed), which can separate plastics having similar specific gravities by the differences in the wettabilities of the particles was developed. Surface modification of plastics with similar wettability enabling separation in the hybrid jig and the effects of wettability control of the plastics using reagents are reported.

Sep 1, 2012

By Jiongtian Liu, Jianjun Wu, Yongzhou Wan, Li Feng

"Mechanical Thermal Expression (MTE) is a developing non-evaporative lignite dewatering technology. It has been shown to effectively dewater high moisture content in low rank coals via the application of mechanical force and thermal energy at elevated temperatures. In this paper, the dewatering behavior of Yunnan Xiaolongtang lignite during the MTE-process was studied. Furthermore, how variations in temperature and pressure during the MTE process affect the surface oxygen functional groups and pore structure were also discussed using Fourier transform infrared spectrometer (FTIR) and mercury intrusion porosimetry (MIP). Increases in MTE temperature and pressure resulted in significant reductions in residual moisture content and moisture holding capacity, along with the increase of fixed carbon content and reductions of other elements content, especially oxygen content, which have been largely attributed to the destruction of the surface oxygen functional groups and porosity in lignite. The optimized technology conditions are temperature 150~220°C and pressure 7~10MPa. The residual moisture content of the lignite treated by MTE under the conditions of 200°C and 10MPa is decreased to 8%, while the dewatering rate exceeds 76 % and the calorific value approaches 22 MJ/kg. The experimental results offer a deeper understanding of the influence of process parameters on the lignite stuctures and properties. The reduction in residual moisture content, surface oxygen functional groups and pore volume under increasingly severe MTE conditions are suggestive of the structure changes that accompany increased coalification (rank) within the lignitic range."

Jan 1, 2014

By Reza M. Rahman, Seher Ata, Graeme J. Jameson

"This paper presents the results of a through investigation into the froth recovery measurements in a controlled plant environment using a device that allows direct collection of dropback particles from the froth phase. Test work was performed at the Northparkes concentrator (NSW, Australia), using a feed taken from the head of the cleaner scavenger bank. The feed slurry had a relatively higher copper grade varying from 5.2% to 6.8%. Experiments were performed to investigate the effect of important flotation parameters such as air flowrate on the froth recovery. The size of the particles in the relevant streams was also analysed to acquire in-depth knowledge about the froth dropback mechanism. The results suggested that the froth recovery could be as low as 70%, although it was relatively easy to achieve the values in the range 75% to 85% by the correct choice of operating variables. It was found that the air flowrate has a positive impact on both collection (pulp) and froth zone recoveries. However, the effect was more prominent in the froth zone. It appeared that the froth recovery is a strong function of particle size."

Jan 1, 2014

By M. M. Fan

In Florida?s phosphate industrial practice, the most favorable upper size limit of froth flotation is 1.18 mm which corresponds to particle weight of about 2.8 mg. Conventional froth flotation is not efficient in upgrading coarse particles (+0.425-1.18 mm). A limited number of studies have been devoted to understanding and improving coarse particle flotation. We have shown that the coarse particle flotation performance can be significantly improved by the presence of picobubbles generated by hydrodynamic cavitation. In this study, the size of picobubbles produced under certain hydrodynamic conditions was measured by a laser particle size analyzer. A size-by-size flotation performance analysis of coarse phosphate froth flotation in the presence of picobubbles is conducted in terms of flotation kinetics, selectivity and recovery. It was found that picobubbles doubled the flota-tion rate, increased the P2O5 recovery more significantly for +0.85-1.18 mm particles than +0.425- 0.6 mm and +0.60-0.85 mm particles. At a given acid insolubles (A.I.) rejection, the presence of picobubbles increased the P2O5 recovery by up to about 25%.

Jan 1, 2014

By B. Q. Xiao

The nitrate content is an important factor for environmental water samples and flour. In a 0.35 mol/L H2SO4-2NO solution, has a strong catalyzing function on the decolourization of Gallocya-nine (GC) oxidated by NaBrO3. Based on this, a novel method was developed to measure the NO and -3NO concentrations in water and flour. The flow injection technology was introduced into the analysis system. A single-valve dual- cingulums to inject which the Copperized-Cadmium slice and the reduction zone are isolated. The optimum solution for this method contains 1.48×10-4 mol/L GC, 0.06 mol /L NaBrO3 and 0.2 mol /L of NH4-2NOCl. Two empirical equations were proposed to calculate the and -3NO concentrations based on the measured signals. It can be used to measure -2NO of from 0.001 mg / L to 2.0 mg/L and -3NO of from 0.002 mg / L to 2.5 mg/L. The measurement frequency can be up to 20 samples / h. The relative standard deviation for eleven samples is less than 5%.

Jan 1, 2014

By A. T. Sutaone

"In the Dongri Buzurg Manganese Mine of M/s Manganese Ore (India) Ltd., high grade lumpy manganese ore required for iron and steel industries is produced through multi-stage crushing and screening. This has resulted in accumulation of 50,000 tonnes of low grade fines over the years. This production of such fines is still going on. The fines create environmental problems, like air and water pollution and siltation in adjoining fields. Besides containing lot of manganese values, they occupy large space which is very scare in mining area.The Indian Bureau of Mines under one of its statutory functions has suggested the company to explore the possibility of recovery of additional values under conservation and environmental aspects. Hence the company has sponsored a bulk sample for beneficiation studies in the Modern Mineral Processing Laboratory and Pilot Plant of Indian Bureau of Mines at Nagpur, India. The main manganese minerals present in these mine rejects have been identified as pyrolusite and psilomelane. The purpose of this study was to explore the possibility of evolving a suitable beneficiation flowsheet to obtain manganese concentrates assaying over 72% MnO2 to be used as raw material for the manufacture of dry cell batteries.The sample/material was subjected to characterisation studies in terms of chemical analysis, granulometry and mineralogical compositions. Based on these characterisation studies, the beneficiation process developed comprised of desliming, jigging and low intensity magnetic separation mainly to reject quartz, silicates and jacobsite. The manganese concentrate thus produced assayed 70.2% MnO2 with MnO2 recovery of 78% and weight per cent yield of 63.5. This natural concentrate could be mixed with the electrolytic manganese dioxide produced by the company and this blend can thus be used as a raw material for the manufacture of dry cell batteries by the end users. The paper deals with the details of test work carried out in evolving the process flowsheet."

Jan 1, 2003

By Y. E. Brylyakov, M. A. Kostrova

"The apatite staffelite ores (ASO) of Kovdor deposit are dominated by fine-grained aggregates containing both phosphate minerals and silicates — vermiculite, smectites, zeolites. These minerals exhibit ion-exchange properties. In this connection, the magnitude of cation exchange, along with the content of P2O5 and CO2, is an important property of apatite staffelite ore, which largely determines the performance of concentration processes. In the examined ASO samples, the magnitude of cation exchange measured in terms of Ca2+ is 2546-4790 g/ton. The conducted laboratory studies of apatite staffelite ores with various mineral composition showed that adding calcined soda improves the recovery of P2O5 into the flotation concentrate. Full-scale tests were conducted at the apatite staffelite ore processing plant at Kovdor Mining and Concentration Operation and demonstrated the high performance of the proposed agent treatment. The test results showed that in the flotation of apatite staffelite ores, the optimum calcined soda feed rates range from 3,500 to 5,000 g/ton of the flotation feed. With close flotation feed and concentrate grade parameters, the P2O5 recovery gain is 17%. The effect of adding soda is associated with the desorption of the hardness cations from the minerals, precipitation in the pulp and, accordingly, improvement in the ionic composition of the liquid phase of the flotation feed due to a reduced content of calcium ions. Based on the test results, the proposed agent treatment with an elevated feed rate of calcined soda was implemented at Kovdor Mining and Concentration Operation in the flotation of apatite staffelite ore. The apatite staffelite ores (ASO) of Kovdor deposit are dominated by fine-grained aggregates containing both phosphate minerals and silicates — vermiculite, smectites, zeolites. These minerals exhibit ion-exchange properties. These minerals have certain properties requiring a more detailed examination for a better understanding of the flotation properties of apatite staffelite ores."

Jan 1, 2018

By Francis Pitard

"The optimization of metallurgical processes requires an in-depth understanding of the heterogeneity carried by any constituent of interest. It emphasizes that knowledge of the Theory of Sampling (TOS) is the necessary step to ensure that valuable and valid research programs, pilot plants, feasibility studies, plant design and plant operations have been set on solid foundations. Too many publications today are solely based on the properties of the sample, with no mention of how this sample relates to anything in the environment where it was collected. Unfortunately sampling is an error-generating process that leaves no apparent tracks of its shortcomings. Indeed, it is easier to track down analytical errors than sampling errors. Consequently, bad sampling practices plague the scientific community and the industry and are responsible for severe money losses, unsatisfactory science and processing, and sometimes litigation. A point-by-point strategy is presented addressing sampling problems in early stages of a project. Sampling system requirements for metallurgical accounting and process control are listed. The use of Chronostatistics is suggested to determine if sampling systems are performing satisfactorily and to identify the various types of process variability that may not be easily detected by a conventional inspection of available chronological data. This strategy will help engineering firms, manufacturers, managers and supervisors to provide, install, use and maintain key sampling systems located at very important points in a process. Equipped with the appropriate sampling and statistical tools it becomes easier to minimize reconciliation problems with the mine, with suppliers and with clients. Contrary to the beliefs of many people, good sampling systems are not expensive because in the long run they help to reduce hidden cost and better regulate plant productivity; they most certainly minimize the number of unnecessary meetings looking for solutions where there are none. The suggested strategy will help specialists to extract maximum information from the available data, as large investments and crucial decisions depend on it."

Jan 1, 2014

By Kobus (J. J. ) Rossouw, P. Chris Pistorius, Johannes Sono

"Different coal properties are important in SL/RN (coal-based rotary kiln) direct reduction of iron ore, and in electrical smelting of prereduced iron ore. Laboratory simulation was used to evaluate two candidate coals, which were similar in volatile content and rank, but differed in reactive maceral content. The tests served to evaluate both the reduction rate (during direct reduction) and the dissolution rate of carbon from the coal into an iron bath.Reduction rates of mixtures of magnetite and devolatilised coal were assessed isothermally, using samples of 55 grams. The off-gas analysis was used to follow the extent of reduction. Results are shown in Figure 1 a). Coal B was expected to be more reactive, based on its higher content of reactive macerals (77%, compared with 61% for Coal A). In line with this, Figure 1 a) does show a higher reduction rate with this coal. However, increasing the reduction temperature increases the reduction rate substantially,especially for the less-reactive Coal A.For the dissolution experiments, samples (mass: 250 g) were melted in an alumina crucible (under a nitrogen atmosphere), to give a starting composition around 1%C. When the desired temperature was reached, 25 g of char was added on top of the melt, through a feeding port. Results are shown in Figure 1 b). The more-reactive Coal B was less crystalline (the graphite crystallite size estimated from X-ray diffraction was 4.6Å, compared with 11.4Å for Coal A). This is associated with a lower dissolution rate in iron."

Jan 1, 2003

By C. Raghu Kumar

Hydraulic or teetered bed separators (TBS) are finding new avenues for application in the field of mineral processing. Floatex Density Separator (FDS) is a hydraulic/teetered bed separator capable of operating at high tonnage due to its advanced instrumentation. FDS/TBS is being used in Indian mineral sand industry for classification and segregation of different minerals. The purpose of this paper is to provide details on the performance of the plant scale FDS in recovering the chromite from feed (below 1mm size). Historically this feed has been processed using hydrocyclones and spiral classifiers; however, there is a strong trend now to employ teetered bed separators, thus allowing significant changes to be made in the plant for improving process efficiency. In the present work, the performance of the plant scale FDS is described in terms of partition curve (yield, cut size, classification efficiency/Ep) for different combination of process variables and also in terms of metallurgical grade and recovery. It is found that, efficient classification can be achieved at a maximum cut size of 380 µm with and the imperfection is also reported as low as 0.16. The grade of the underflow product is enriched as maximum as 52.2% Cr2O3 from a feed assaying 40.4% Cr2O3.

Sep 1, 2012

By V. F. Bannikov, A. P. Kozlov

"The purpose of this study was to develop a theoretical and technology framework for designing new combined technologies for processing tailings containing non-ferrous and noble metals using dry separation. The main goals of the study were: identifying the distribution patterns of valuable components in various fractions in dry separation processes; examining the patterns identified for different types of non-ferrous and noble metal tailings; developing a theoretical and technology foundation for the development of innovative technologies for the efficient processing of tailings with minimal process water consumption. To examine the possibility of efficient recovery of valuable components from refractory tailings using dry separation, an experimental laboratory unit was designed and built, composed of novel or modified lab equipment: plasma unit for increasing the magnetic susceptibility of Fe - containing minerals; magnetic separator supporting isodynamic and polygradient fields; pneumatic separator for the dry separation of finely dispersed mineral mixtures; dielectric separator using the resonant frequency of the electric field. The laboratory unit supports various modifications and combinations of the lab equipment. The experimental studies led to the development of a unified process scheme for lab tests of mature and non-ferrous smelter tailings using dry separation methods.INTRODUCTION The huge amount of waste from mining and processing of mineral resources Russia inherited from the extensive use of mineral resources in the Soviet Union and amount of waste continue to grow. Often the content of valuable non - ferrous, rare and noble metals in waste exceeds the balance contents in natural ores of the developed deposits. The availability of a rich scientific reserve for the creation highly effective innovative technologies for waste processing determines the necessity of the acceleration in the resolution of problems of the complex assessment, capitalization and involvement in the processing of technogenic resources in Russia (Chanturiya and Kozlov, 2014.)."

Jan 1, 2018

By P. S. Mukherjee

Mineral ilmenite is a major resource for titanium, whose major application is for production of Titanium dioxide (TiO2) for pigment application. The production of pigment grade TiO2 from ilmenite was earlier carried out by acid leaching, which has now been banned due to environmental regulations. Further acid leaching leads to loss of iron metal values as sulphate or chloride which are also treated as effluent. In thermal plasma processing the metal values are recovered as high value pig iron and Titanium dioxide is recovered as Titania rich slag containing 80 to 85 percent TiO2. The Titania rich slag has now been considered as a better input material than synthetic rutile for production of pigment grade Titanium dioxide. On the other hand, high value pig iron goes for automobile industry for specific application. An Inflight-flight Thermal Plasma Processing plant, used for the production of Titania Rich slag and high value Pig iron from ilmenite, with 20kg capacity was designed and fabricated. The reactor has the provision to utilize the flue gas generated for preheating the input of raw materials. Various aspects of designing the furnace operation include viz. Feeding the raw material at a fixed rate, designing the crucible used for melting ilmenite, proper cooling arrangements, an innovative method for tapping the melt, recovery of heat from the gases, various safety arrangements which are some of the important milestone of the present work. The various operations have been carried out through a controller panel. Experiments were carried out to optimize various processing parameters using statistical modeling. Large scale experiments have been carried out at 10 to15 kg scale. The material balance has been calculate, and it has been observed, that about 95 percent recovery could be obtained for both Iron and Titanium oxide from ilmenite. The detailed characterization on Titania rich slag and iron has been carried out. It has also been shown that using the above slag, it is possible to prepare nanosized Titanium dioxide powder containing about 98 percent Titanium dioxide by optimizing leaching conditions. Keywords: titania rich slag, ilmenite, thermal plasma

Sep 1, 2012

By Heinrich Hutchison, Thomas von Moltke, Roelof F. Sandenbergh, Katarina P. Cerovic

In the leaching of gold in aqueous cyanide solutions the rate of gold leaching may be decreased by the passivation of the gold, that may however be prevented or reversed in the presence of lead species in solution. In the present study potentiostatic, potentiodyanamic and XPS (X-ray photoelectron spectroscopy) analysis were used to further clarify the action of lead ions on the anodic activity of gold in alkaline cyanide solutions. It was found that lead increased the gold dissolution rate as it deposited on the gold surface at potentials more positive than its reversible Nernst potential for bulk metal deposition, i.e. by underpotential deposition mechanism, but that it decreased gold activity if present as bulk plated lead on the gold.

Jan 1, 2003

By T. Fujita

A high-grade fluorite ore is converted into hydrogen fluoride to produce many kinds of materials containing fluorine. Recently, it is becoming necessary to use low-grade fluorite ore due to the depletion of high grade ore. The low-grade fluorites usually have impurities such as SiO2, P, CaCO3 and arsenic. The most impurities such as SiO2, CaCO3 and P can be removed by using flotation method. However, the removal of arsenic is difficult, and the arsenic contamination decreases the hydrogen fluoride production percentage. The novel technologies for processing low-grade fluorite ore are urgently needed, in order to lower the arsenic concentration to less than 100 mg/kg. In this study, the removal of arsenic from low-grade fluorite ore has been investigated by means of an autogenous grinding using tower mill in sulfuric acid aqueous solution and 0.3 mm zirconia balls in water. The nano grinding in water can prevent the dissolution of 0.3 mm size zirconia balls as grinding media by sulfuric acid solution. Experimental results showed that the arsenic concentration was reduced from 260 mg/kg to 90 mg/kg and CaF2 recovery reached 90% by this process.

Sep 1, 2012

By Z. Kwela, A. Manhique, W. W. Focke, W. van der Merwe

"The main features of the de Wet improved alkali fusion process for the manufacture of AZST are: Fewer process are steps necessary; radioactivity is removed by leaching rather than by precipitation; fewer waste streams are generated; there is less waste to discard and alkali reagent is recovered in the form of a sodium silicate solution that is essentially free of radioactivity.Here we report on our efforts maximize the alkali recovery in the sodium silicate product stream: Milled zircon, d50 ˜ 9 µm, was fused with caustic soda pearls in open reaction vessels at temperatures between 650°C and 850°C. Fusion times of 1, 2, 4, 24 and 336 hours (with intermittent milling) were investigated. The fusion products were characterized by infrared spectroscopy, X-ray diffraction and by wet chemical analysis.For prolonged fusion times the fusion products approached equilibrium compositions. However, the phases Na2ZrSiO5 and Na4Zr2Si3O12 observed at 850°C did not form at 650°C. Since these compounds do not hydrolyze in water they limit the recovery of alkali in the sodium silicate product stream. For 2-hour fusions a broad spectrum of non-equilibrium reaction-products, that are rich in sodium silicates, is formed."

Jan 1, 2003

By Yuqing Feng, Ping Fang, Dezhou Wei, Zichuan Guan, Shuling Gao, Baoyu Cui

"Air core, as an inevitable phenomenon of rotational flow field inside hydrocyclone, has a major impact on hydrocyclone’s separation characteristics. The air core formation process, its structural features and its influencing factors were investigated systematically in this paper. Numerical study on the air core of a f50 mm hydrocyclone was carried out using a commercial computational fluid dynamics (CFD) modelling software package ANSYS/Fluent with the selection of Reynolds Stress Model (RSM) for the turbulence model and Volume of Fluid (VOF) for capturing the air-liquid interface. Physical experiments were conducted under the same geometry and operation conditions and the particle image velocimetry (PIV) technology was used to measure the liquid flow. The CFD results are compared with the experimental measurement with good agreement demonstrated. The air core was formed generally at around 0.7 s, air outsides of the air core was eliminated completely after 1.7 s. The centreline axial velocities and the water blocking hydrocyclone simulations showed that air of the air core entered the hydrocyclone from the underflow area and exhausted from the overflow area, but there was also some air flowing into the air core from the overflow area. The largest swing of the air core occurred on the top of the underflow pipe, and a protuberance similar to the shape of Adam’s apple appeared when the air entered the vortex finder. CFD simulation results also showed that the air core diameter was decided by axial position and parameters of hydrocyclone. The structural parameters have more effects on the air core diameter than the operational parameters."

Jan 1, 2014