The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Bahram Rezai - One of the best experts on this subject based on the ideXlab platform.
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investigation of bubble particle attachment detachment and collection efficiencies in a mechanical Flotation cell
Powder Technology, 2020Co-Authors: Hossna Darabi, D.a. Deglon, Bahram Rezai, S Javad M Koleini, Mahmoud AbdollahyAbstract:Abstract The paper presents the effect of impeller speed and superficial gas velocity on bubble-particle attachment, detachment and collection efficiencies using pure quartz particles in a mechanical Flotation cell. Detachment and collection efficiencies in different parts of cell were calculated by local turbulent energy dissipation Rate measurements using high speed stereoscopic particle image velocimetry technique. In addition to high detachment efficiency, low attachment efficiency is also one of the reasons for low collection efficiency for coarse particles. The Flotation Rate constant increased with an increase in superficial gas velocity. However, the effect of superficial gas velocity on collection efficiency was negligible. This means that any effect of superficial gas velocity on Flotation Rate constant was due to changes in the number of bubbles and collision frequency. The Flotation Rate constant, collision frequency, and the number of bubbles increased with increasing impeller speed. However, collection efficiency decreased with increasing impeller speed.
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the effect of micro turbulence on quartz Flotation Rate
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2015Co-Authors: Behzad Shahbazi, Bahram RezaiAbstract:In this research, the effect of micro turbulence on the Flotation Rate of quartz particles was investigated. The maximum particle Reynolds number (Rep) was obtained at 60.25 with a particle size of -500+420 µm, impeller speed of 900 rpm, bubble surface area flux of 10.21 1/s and micro scale turbulence size of 162 µm. When the micro turbulence size was equal to the particle size, the maximum Flotation Rate of coarse particles (Rep>10) was obtained at 1.47 1/min.
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effect of dimensionless parameters and bubble surface area flux on Flotation Rate constant
Journal of Dispersion Science and Technology, 2015Co-Authors: B Shahbazi, Bahram RezaiAbstract:In this study, the effect of dimensionless hydrodynamic parameters (Reynolds Number–Re, Froude Number–Fr, and Weber Number–We) and bubble surface area flux, S b, on Flotation Rate constant, k, of quartz particles was investigated using laboratory mechanical Flotation cell. Maximum Flotation Rate constant was obtained at Re = 89, 800, Fr = 2.4, and We = 1558. For either more quiescent (Re 98, 000 and Fr > 2.85) conditions, Flotation Rate constant decreased steadily. Furthermore, the effect of Reynolds number in the k–S b relationship was investigated, and model of was obtained.
Yong Tian Wang - One of the best experts on this subject based on the ideXlab platform.
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effects of particle size on lignite reverse Flotation kinetics in the presence of sodium chloride
Powder Technology, 2013Co-Authors: Haijun Zhang, Yijun Cao, Jiongtian Liu, Yong Tian WangAbstract:Abstract The purpose of this study was to investigate the effect of particle size on lignite reverse Flotation with a focus on reverse Flotation kinetics in the presence of sodium chloride. Six Flotation kinetic models were applied to data from the tests using the 1stOpt statistical analysis software package to estimate the relationship between the Flotation Rate constant, the maximum ash Flotation recovery and the particle size. Within the range studied, the best reverse Flotation performance was obtained at a grinding fines (− 74-μm size fraction) content of 42.34% with a concentRate ash content of 11.30% at 65.29% combustible recovery after 20 min of Flotation time. The results show that all kinetic models except the classical first-order Flotation kinetic model gave excellent fits to the experimental data under various grinding fines contents and various size fractions. The high Flotation Rate constant was limited to a narrow particle size range. The maximum Flotation Rate constant was obtained at a grinding fines content of 42.34% and with the − 250 + 150 μm fraction. We concluded that the reverse Flotation of lignite in the presence of sodium chloride can be described with the first-order and second-order models. Furthermore, the reverse Flotation performance as a function of particle size was further evaluated using the reverse Flotation efficiency index. We found that the − 425-μm size fraction with a grinding fines content of 42.34% resulted in the greatest index value compared with the investigated narrow size fractions at any given Flotation time.
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study on kinetic modelling for fine coal Flotation
International Journal of Coal Preparation and Utilization, 2013Co-Authors: Gan Cheng, Yong Tian WangAbstract:Flotation models are useful for practical quantitative work, many are widely used to assist in the design of new equipment and processes. The analyses of petrographical composition, size fraction, and density distributions of the coal sample were used to detect its floatability and quality characteristics. The Flotation Rate constant k values of the five traditional kinetic models parameters were calculated by software MATLAB7.0. In addition, we discussed a new kinetic model-fitting approach for coal Flotation. Results show that the main gangue mineral in the fine coal is kaolinite. The middle density fraction of 1.40–1.60 g/cm3 has a high yield, which indicates that the coal sample is not easy to sepaRate. The k value can reflect the floatability. During the Flotation process, the k value decreases, and the floatability worsens. The experimental data of various size fractions show that the new modified model has more advantages compared with the five traditional models. The correlation coefficient (R 2) ...
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study on size and density distribution in fine coal Flotation
International Journal of Coal Preparation and Utilization, 2013Co-Authors: Gan Cheng, Yong Tian Wang, Hongxiang Xu, Qi Zhang, C A SongAbstract:Mineral composition, size fraction, and density distributions of a fine coal sample were used to determine its floatability and quality characteristics. Flotation Rate tests were conducted using different agitation speeds of Flotation machines. The results showed that the ash of clean coal product increased gradually with increasing agitation speed and the floatability of coal became poor. The higher the agitation speed, the faster the Flotation Rate was. For coarse size coal with higher density, the recovery was low. For the same size particle and density, the higher the agitation speed, the higher the recovery. The relationship between energy (E) and recovery (ϵ) were estimated through the cubic expression. The model parameters were calculated using software MATLAB7.0. The experimental data of various size fractions showed that the fitting of the model was very good.
Patrice Nortier - One of the best experts on this subject based on the ideXlab platform.
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Flotation DE-INKING OF 50% ONP/ 50% OMG RECOVERED PAPERS MIXTURES USING NONIONIC SURFACTANT, SOAP, AND SURFACTANT/SOAP BLENDS
Bioresources, 2010Co-Authors: Jeremy Allix, Elisa Zeno, Davide Beneventi, Patrice NortierAbstract:A laboratory Flotation column equipped with Venturi aerators and an adjustable froth removal system was used to study the effect of calcium soap and a mixture of calcium soap/alkyl phenol ethoxylate surfactant on ink and fibres transfer during Flotation de-inking of a 50% old newprint (ONP) / 50% old magazines (OMG) recovered papers mixture. Mass transport phenomena determining the yield of the Flotation process were interpreted using model equations describing particle removal in terms of Flotation, entrainment, and drainage in the froth. A decrease in the ink and mineral fillers Flotation Rate constant, drainage through the froth, and in fibre entrainment was observed when increasing the surfactant concentration. These trends were consistent with the typical dispersing action of the studied nonionic surfactant. An opposite effect on ink and fillers was observed when using calcium soap alone, and the increase in the Flotation Rate constant and drainage through the froth were consistent with the collecting and defoaming action of the calcium soap. Moreover, fibre entrainment decreased when increasing the soap concentration. The study of the surfactant/soap mixture highlighted the absence of synergy between the calcium soap and the surfactant.
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Flotation de inking of 50 onp 50 omg recovered papers mixtures using nonionic surfactant soap and surfactant soap blends
Bioresources, 2010Co-Authors: Jeremy Allix, Elisa Zeno, Davide Beneventi, Patrice NortierAbstract:A laboratory Flotation column equipped with Venturi aerators and an adjustable froth removal system was used to study the effect of calcium soap and a mixture of calcium soap/alkyl phenol ethoxylate surfactant on ink and fibres transfer during Flotation de-inking of a 50% old newprint (ONP) / 50% old magazines (OMG) recovered papers mixture. Mass transport phenomena determining the yield of the Flotation process were interpreted using model equations describing particle removal in terms of Flotation, entrainment, and drainage in the froth. A decrease in the ink and mineral fillers Flotation Rate constant, drainage through the froth, and in fibre entrainment was observed when increasing the surfactant concentration. These trends were consistent with the typical dispersing action of the studied nonionic surfactant. An opposite effect on ink and fillers was observed when using calcium soap alone, and the increase in the Flotation Rate constant and drainage through the froth were consistent with the collecting and defoaming action of the calcium soap. Moreover, fibre entrainment decreased when increasing the soap concentration. The study of the surfactant/soap mixture highlighted the absence of synergy between the calcium soap and the surfactant.
Haijun Zhang - One of the best experts on this subject based on the ideXlab platform.
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Effects of particle size on the Flotation behavior of coal fly ash.
Waste Management, 2019Co-Authors: Lu Yang, Danlong Li, Haijun ZhangAbstract:Abstract The effect of particle size on the Flotation behavior of coal fly ash was investigated in this study. Three narrow particle size fractions, −125 + 74 μm, −74 + 45 μm, and −45 μm, and the unclassified particle size fraction of −500 μm of coal fly ash were chosen to study the basic properties by the measurement of induction time, contact angle, and wetting heat. Furthermore, Flotation kinetic tests of coal fly ash with different particle size fractions were conducted. The results show that particle size significantly affects the Flotation kinetics of coal fly ash, and the intermediate particle size fractions of −125 + 74 μm and −74 + 45 μm had better Flotation performance and higher Flotation Rate than the fine particle size of −45 μm. Six Flotation kinetic models were used to fit the test data of the cumulative unburned carbon recovery in the coal fly ash Flotation. The parameters of Flotation Rate (k), maximum unburned carbon recovery (e∞), and correlation coefficient (R2) were analyzed in detail. The fitted results from the data showed that, for each size fraction, the froth Flotation of coal fly ash can be best described by the classical first-order model.
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effects of particle size on lignite reverse Flotation kinetics in the presence of sodium chloride
Powder Technology, 2013Co-Authors: Haijun Zhang, Yijun Cao, Jiongtian Liu, Yong Tian WangAbstract:Abstract The purpose of this study was to investigate the effect of particle size on lignite reverse Flotation with a focus on reverse Flotation kinetics in the presence of sodium chloride. Six Flotation kinetic models were applied to data from the tests using the 1stOpt statistical analysis software package to estimate the relationship between the Flotation Rate constant, the maximum ash Flotation recovery and the particle size. Within the range studied, the best reverse Flotation performance was obtained at a grinding fines (− 74-μm size fraction) content of 42.34% with a concentRate ash content of 11.30% at 65.29% combustible recovery after 20 min of Flotation time. The results show that all kinetic models except the classical first-order Flotation kinetic model gave excellent fits to the experimental data under various grinding fines contents and various size fractions. The high Flotation Rate constant was limited to a narrow particle size range. The maximum Flotation Rate constant was obtained at a grinding fines content of 42.34% and with the − 250 + 150 μm fraction. We concluded that the reverse Flotation of lignite in the presence of sodium chloride can be described with the first-order and second-order models. Furthermore, the reverse Flotation performance as a function of particle size was further evaluated using the reverse Flotation efficiency index. We found that the − 425-μm size fraction with a grinding fines content of 42.34% resulted in the greatest index value compared with the investigated narrow size fractions at any given Flotation time.
John Ralston - One of the best experts on this subject based on the ideXlab platform.
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reducing uncertainty in mineral Flotation Flotation Rate constant prediction for particles in an operating plant ore
International Journal of Mineral Processing, 2007Co-Authors: John Ralston, S R Grano, Jinming Duan, Daniel Fornasiero, T AkroydAbstract:Abstract We have demonstRated that it is possible predict the recovery of a hydrophobic value mineral using a complex, fundamentally derived, property-based model. We have applied this model to an operating plant, with a satisfactory outcome. The property-based model allows the relative effects of particle size, particle contact angle and cell hydrodynamics to be discerned. The property-based model may allow more effective benchmarking and optimisation of Flotation circuits. Work is currently underway to validate and extend various parts of this model at both laboratory and plant scale.
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calculation of the Flotation Rate constant of chalcopyrite particles in an ore
International Journal of Mineral Processing, 2003Co-Authors: Jinming Duan, Daniel Fornasiero, John RalstonAbstract:Abstract The Flotation recovery of chalcopyrite particles in a complex sulfide ore was measured in a Rushton turbine Flotation cell as a function of particle size. The experimental Flotation Rate constants of these particles were compared to those calculated using a recently developed Flotation model that incorpoRates contributions from the efficiencies of collision, attachment and stability between particles and bubbles, as well as their frequency of collision. For these calculations, the contact angle of the chalcopyrite particles in the ore was obtained independently using an approach based upon Time of Flight Secondary Ion Mass spectroscopy (ToF-SIMS). It was found that the calculated Flotation Rate constants were in good agreement with the experimental data and able to reproduce the characteristic maximum in Flotation Rate constant for particles of intermediate size. The values of bubble velocity and turbulent dissipation energy derived from these calculations are relatively low and may well correspond to mean values of these parameters inside the Flotation cell.
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investigating fine galena recovery problems in the lead circuit of mount isa mines lead zinc concentrator part 1 grinding media effects
Minerals Engineering, 1999Co-Authors: V J Cullinan, C.j Greet, N.w. Johnson, S R Grano, John RalstonAbstract:A plant survey was carried out on the lead secondary rougher and scavenger banks of the Lead/Zinc Concentrator of Mount Isa Mines Limited. Sizing analysis of the survey samples demonstRated that a major limiting factor to overall lead recovery in this section of the plant was the diminished recovery of the fine galena in the minus 5 microns particle size fraction. Batch Flotation experiments were carried out on a plant sample of lead secondary rougher feed and a sample of rod mill feed ore. Mineral recovery-size data for these tests showed similar fine galena Flotation behaviour to that observed in the plant. Increased collector addition did not improve either the maximum recovery or the Flotation Rate constant of the fine galena but did reduce the selectivity of galena against sphalerite. Changing of the grinding media used for the ore sample from a high carbon steel to a high chromium alloy steel resulted in a significant increase in the maximum recovery and Flotation Rate constant of the fine galena. EDTA (ethylene diaminetetraacetic) extractable iron measured for the high carbon steel media were similar in magnitude to those measured within the plant and were higher than those measured for the high chromium alloy steel media. The increased surface concentration of hydrophilic layers of oxidised iron species on the fine galena was a likely reason for their diminished Flotation behaviour both in the laboratory and in the plant.
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recovery mechanisms for pentlandite and mgo bearing gangue minerals in nickel ores from western australia
Minerals Engineering, 1997Co-Authors: M C Pietrobon, S R Grano, S Sobieraj, John RalstonAbstract:Abstract The Flotation behaviour of a Western Australian nickel ore was characterised by size-by-size Flotation Rate tests to extract Rate constant information. The aim was to identify the effect of surface interactions on the Flotation of the nickel sulphide mineral, pentlandite, with magnesium-silicate bearing minerals (predominantly serpentines). Flotation tests were carried out using collector (amyl xanthate), both with and without the other standard reagents for this ore. In this study the latter were carboxy-methyl cellulose (CMC) and soda ash. The addition of soda ash and CMC was shown to improve pentlandite Flotation Rate and recovery. Soda ash addition was found to be essential for improving Flotation performance, as without it nickel recovery was unacceptably low. It is proposed that carbonate ions, derived from soda ash addition, enhance dispersion in the pulp and that CMC may assist removal of adhering slime particles from pentlandite surfaces. Drawing on the literature in this area, a number of mechanisms are proposed to explain the observed Flotation behaviour of gangue magnesium-silicate bearing minerals.
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methods to increase fine mineral recovery in the mount isa mines lead zinc concentrator
Minerals Engineering, 1997Co-Authors: G L Small, John Ralston, S R Grano, N.w. JohnsonAbstract:Abstract Methods to increase the Flotation Rate of fine (-10 μm) galena relative to sphalerite contained in a lead process stream have been examined. These included sepaRate conditioning and Flotation of the fine and coarse particles, both in the presence and absence of High Intensity Conditioning (HIC). Size separation before conditioning and Flotation was by conventional hydrocyclone, producing overflow (p8o =10 μm) and underflow, (p80 =80 μm) streams. Flotation of the sepaRately treated fine particles was compared to that of the fine particles in the unclassified stream. The parameter examined was collector concentration. The Rate o f galena Flotation in the overflow stream was found to be inferior relative to that in the undertow stream, even at high collector concentrations to the overflow stream. However, galena Flotation in the overflow stream was more selective against sphalerite than in the undertow stream. This was ascribed to greater levels of galena liberation in the finer stream. The Rate of galena Flotation in the undertow stream was reduced at high collector concentrations. This phenomenon was ascribed to removal of the fines causing the remaining coarse hydrophobic panicles to destabilise the froth. SepaRate conditioning was found to result in the selectivity of galena against sphalerite to be slightly inferior to the unclassified feed. This was due to poor galena/sphalerite selectivity in the undertow stream. The galena Flotation Rate increased in all streams with High Intensity Conditioning.