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Bahram Rezai - One of the best experts on this subject based on the ideXlab platform.
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Influence of surface roughness on Flotation Kinetics of quartz
Journal of Central South University, 2012Co-Authors: Mehdi Rahimi, Mohammad Reza Aslani, Bahram RezaiAbstract:Surface roughness of quartz particles was determined by measuring the specific surface area of particles. The wettability characteristics of particles were determined by measuring the Flotation rate using a laboratory Flotation cell. Experimental results show that the rod mill product has higher roughness than the ball mill product. For the particles with larger surface roughness, the Flotation Kinetics constant is also higher. Finally, empirical relationships between surface roughness ( r ) and the Flotation Kinetics constant ( k ) of quartz particles as k = A + Br + Cr ^0.5ln r + D /ln r + E/r and k = A + Br are presented, in which A, B, C, D and E are constants related to experimental conditions and mineralogical properties of mineral.
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Influence of the roughness and shape of quartz particles on their Flotation Kinetics
International Journal of Minerals Metallurgy and Materials, 2012Co-Authors: Mehdi Rahimi, Fahimeh Dehghani, Bahram Rezai, Mohammad Reza AslaniAbstract:Surface roughness and shape play an important role on the behavior of particles in various processes such as Flotation. In this research, the influence of different grinding methods on the surface roughness and shape characteristics of quartz particles as well as the effect of these parameters on the Flotation of the particles was investigated. The surface roughness of the particles was determined by measuring their specific surface area via the gas adsorption method. The shape characteristics of the particles were measured and calculated by images obtained by scanning electron microscopy via an image analysis system. The Flotation Kinetics was determined using a laboratory Flotation cell. The results showed that the particles of rod mill products have higher roughness and elongation ratio and lower roundness than the particles of ball mill products. The Flotation Kinetics constant of the particles increased with their surface roughness increasing. Particles with higher elongation and lower roundness indicated higher floatability. In addition, the influence of the surface roughness on the Flotation Kinetics was greater than that of shape parameters.
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a study on the effect of particle size on coal Flotation Kinetics using fuzzy logic
Expert Systems With Applications, 2010Co-Authors: E Abkhoshk, Mohammad Kor, Bahram RezaiAbstract:This paper investigates the effect of particle size on the Flotation Kinetics of coal in a batch Flotation cell. The relationship between Flotation Kinetics constant and theoretical Flotation recovery with particle size was estimated with nonlinear equations. Analysis of variance shows that varying of particle size is statistically significant on Kinetics constant with approximately 96.5% confidence level however it is not significant on maximum theoretical Flotation recovery (RI) in 95% confidence level. Using fuzzy logic method, a multi-input/single-output (MISO) fuzzy model with two input variables: particle size and time and one output variable: cumulative recovery was established to predict the effect of particle size on the Flotation Kinetics of coal in a batch Flotation cell. Application of fuzzy model shows that the results of model fits well to the result of batch Flotation and the fuzzy model can be applied to predict cumulative recovery of different coal particle size. The correlation coefficient (R^2) values of the proposed fuzzy model were 0.986, 0.993, 0.983, 0.977 and 0.972 for [email protected], [email protected], [email protected], [email protected] and [email protected] average particle sizes, respectively.
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relationship between surface roughness of minerals and their Flotation Kinetics
2010Co-Authors: Bahram Rezai, Mehdi Rahimi, Mohammad Reza Aslani, Atiye Eslamian, Fahimeh DehghaniAbstract:Surface roughness is due to fluctuations around a surface solid which plays vital role in subsequent processes. Grinding by different mills causes main changes in surface roughness of particles, which these changes are very important for their Flotation. In this study, surface roughness of quartz particles is determined with measuring of specific surface area of particles. The wettability characteristics of particles with different surface roughness were determined by measuring of Flotation rate using the laboratory Flotation cell. Results have shown that Flotation rate of particles increases with increasing in surface roughness of particles, but this relationship is non linear. Finally, an empirical relationship between surface roughness (λ) and Flotation Kinetics constant (k) of particles such as k = a + bλ0.5 (ln(λ)) + cλ0.5 + dln(λ)/(λ2), has been determined, that a, b, c and d are constants related to experimental conditions and mineralogical properties of mineral.
Yijun Cao - One of the best experts on this subject based on the ideXlab platform.
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Kinetics of bubble particle attachment and detachment at a single bubble scale
Powder Technology, 2020Co-Authors: Haichang Yang, Yijun Cao, Yaowen Xing, Lijuan Sun, Xiahui GuiAbstract:Abstract Bubble-particle attachment and detachment are fundamental subprocesses of Flotation, a deep understanding of which is essential for predicting Flotation Kinetics. This paper focuses on the Kinetics of bubble-particle attachment and detachment at a single-bubble scale. Kinetics experiments of attachment, detachment, and Flotation using coal samples with low-density fraction (LDF), middle-density fraction (MDF), and high-density fraction (HDF) were conducted. Models of bubble-particle attachment and detachment Kinetics were proposed by an analogy with Flotation Kinetics equations. With an increase in coal density, the attachment rate constant decreased, while the detachment rate constant increased, which was consistent with the decrease in floatability of coal. In addition, the experimental data of the attachment and detachment Kinetics was compared with Flotation Kinetics (multi-bubble scale). The optimal fitted models for LDF and MDF were the classical first-order models of attachment/detachment/Flotation Kinetics. These consistencies indicated the floatability of coal could be characterized by the attachment and detachment Kinetics at a single-bubble scale. This was not the case for HDF (gangue minerals in essence), since its optimal models of the attachment/detachment Kinetics were the third-order models, while for Flotation Kinetics was the first-order model with rectangular distribution. This contradiction indicated the Flotation of the high-density particles might be significantly affected by the bubble concentration.
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Flotation Kinetics of easy to float fine coal
Energy Sources Part A-recovery Utilization and Environmental Effects, 2017Co-Authors: Yaowen Xing, Xiahui Gui, Yijun CaoAbstract:ABSTRACTSix Flotation Kinetics models were applied to fit the Flotation Kinetics results of easy-to-float fine coal. It was found that, except for the second-order kinetic model, the rest models are well suited for fitting the experimental data. The rate constant decreased as Flotation time increased, indicating that the particle floatability in the pulp decreased. However, only a slight decrease in the rate constant was observed within 100 s, indicating that the coal samples have good floatability in general. X-ray photoelectron spectroscopy results show that the small proportion of hydrophilic oxygen-containing groups is responsible for the good floatability and fast Flotation Kinetics.
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effects of particle size on lignite reverse Flotation Kinetics in the presence of sodium chloride
Powder Technology, 2013Co-Authors: Jiongtian Liu, Yijun Cao, 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.
Quanzhou Liu - One of the best experts on this subject based on the ideXlab platform.
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comparison of air and oily bubbles Flotation Kinetics of long flame coal
Fuel, 2019Co-Authors: Songjiang Chen, Xiuxiang Tao, Shiwei Wang, Longfei Tang, Quanzhou LiuAbstract:Abstract This paper focuses on the difference in Kinetics of air and oily bubbles Flotation of long-flame coal. Six Flotation kinetic models were taken to fit the air and oily bubbles Flotation results by the software MATrix LABoratory. The findings indicated that the conventional Flotation was greater than the oily-bubble Flotation in Flotation rate in the early stage, and these two Flotation processes exhibited different variation laws in cumulative concentrate yield with Flotation time. Additionally, it was found that the classical first-order model could provide an excellent fit to the experimental data for the conventional Flotation, yet all the studied kinetic models showed a great deviation in fitting to oily-bubble Flotation data. Consequently, an improvement for Flotation kinetic models was conducted by subtracting the delay constant in the oily-bubble Flotation to attain an excellent fitting. Finally, the delay constant for the oily-bubble Flotation was determined to be about 0.7500 min, while the improved classical first-order model was found to give the best fit to the oily-bubble Flotation data. This study may contribute to a better understanding of the oily-bubble Flotation characteristics.
D.a. Deglon - One of the best experts on this subject based on the ideXlab platform.
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the effect of energy input on Flotation Kinetics
International Journal of Mineral Processing, 2016Co-Authors: Mehdi Safari, D.a. Deglon, M C Harris, Laurindo De Salles Leal Filho, Francisco TestaAbstract:Abstract This paper investigates the effect of energy/power input on the Flotation of three sulphide minerals (galena, pyrite & pentlandite) and three oxide minerals (apatite, hematite & quartz) in an oscillating grid Flotation cell (OGC). Oscillating grids generate near ideal hydrodynamic environments, characterised by turbulence which is relatively homogeneous and isotropic. Galena, pyrite, pentlandite (− 150 μm), apatite (− 650 μm), hematite (− 75 μm) and quartz (− 75 μm) were floated in the OGC at power intensities from 0.1 to 5.0 W/kg, using 0.13, 0.24, 0.58 and 0.82 mm bubbles, and at three collector dosages. Results show that the effect of power intensity on the Flotation rate is strongly dependent on the mineral type, particle size, bubble size and collector dosage. In general, fine particles benefit from higher energy inputs, intermediate particles have an optimum energy input, and coarse particles do not benefit from agitation.
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the effect of energy input on the Flotation of quartz in an oscillating grid Flotation cell
Minerals Engineering, 2012Co-Authors: W T Massey, M C Harris, D.a. DeglonAbstract:Abstract This paper investigates the effect of energy input on the Flotation of quartz in an oscillating grid Flotation cell. Oscillating grids exhibit relatively isotropic and homogeneous turbulence. Previous work was limited to power intensities of less than 0.60 W/kg. The current work uses a new oscillating grid cell which operates at much higher power intensities. Quartz (sub 100 μm) was floated in the new cell at power intensities from 0.5 to 5 W/kg and using three discrete bubble sizes (0.13 mm, 0.24 mm and 0.82 mm). Results show that the effect of power intensity on Flotation Kinetics is strongly dependent on both particle and bubble size. For small bubbles, high Flotation rates are achieved at very low power intensities. For larger bubbles, Flotation rates increase with increasing power intensity for fine and intermediate particles, while an optimum power intensity is reached for coarser particles.
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investigating the effect of energy input on Flotation Kinetics in an oscillating grid Flotation cell
Minerals Engineering, 2008Co-Authors: K Changunda, M C Harris, D.a. DeglonAbstract:Abstract This paper investigates the effect of energy input (or agitation) on the Flotation Kinetics of quartz in a novel oscillating grid Flotation cell. Oscillating grids generate near ideal hydrodynamic environments, characterised by turbulence which is relatively homogeneous and isotropic. The cell consists of a 10 l tank agitated by 19 grids, having a mesh size of 8 mm and grid spacing of 18 mm. Flotation tests were performed on methylated quartz particles ( p 80 = 100 μm) over a range of power intensities (0.015–0.60 W/kg) and using three different bubble sizes, generated by sintered glass discs (0.13, 0.24 and 0.82 mm). The Flotation rate constant was found to increases approximately linearly with increasing particle size and to follow an inverse power relationship with the bubble size. These trends are well established in the Flotation literature. More significantly, the Flotation rate constant was found to increase approximately linearly with increasing power intensity for all particle and bubble sizes used in this study. The majority of theoretical and experimental studies have found energy input to have less of an effect than the proportional/linear dependence observed in this study. In addition, the increase in the Flotation rate constant with increasing power intensity was observed to depend on the particle size but to be less dependent on the bubble size. These findings suggest that energy input and bubble size may, respectively play more and less of a role in promoting particle–bubble contacting in turbulent environments than noted in the Flotation literature. However, a recent study by Newell and Grano [Newell, R., Grano, S., 2006. Hydrodynamics and scale up in Rushton turbine Flotation cells: Part 2. Flotation scale-up for laboratory and pilot cells. International Journal of Mineral Processing, 81, 65–78] in a stirred tank has also noted this linear dependence.
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A model to relate the Flotation rate constant and the bubble surface area flux in mechanical Flotation cells
Minerals Engineering, 1999Co-Authors: D.a. Deglon, F. Sawyerr, Cyril T. O'connorAbstract:Abstract Two recent Flotation models developed by the authors are discussed, viz. the bubble population balance model and the attachment-detachment model. The bubble population balance model describes the history of a bubble population in a Flotation cell in terms of the sub-processes of bubble breakage and coalescence. The attachment-detachment model allows for the presence of a gas phase in the Flotation cell, both in terms of a gas residence time and the attachment and detachment of mineral particles to/from bubbles. When combined the two models predict a near-linear region about a point of inflexion on the (simulated) response between the Flotation rate constant (k) and the flux of bubble surface area through the Flotation cell (S b ). It is proposed by the authors that this region corresponds to the linear k−S b relationship observed in a recent research project on Flotation Kinetics in mechanical Flotation cells by Gorain et al. (1997).
Xiangnan Zhu - One of the best experts on this subject based on the ideXlab platform.
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Surface hydrophobicity of sub-bituminous and meta-bituminous coal and their Flotation Kinetics
Fuel, 2019Co-Authors: You Zhou, Boris Albijanic, Bogale Tadesse, Yuling Wang, Jianguo Yang, Xiangnan ZhuAbstract:Abstract This paper discusses the relationships between the surface properties of the sub-bituminous and meta-bituminous coal and their Flotation properties. Additionally, it was investigated whether the Flotation kinetic constants, obtained using various Flotation kinetic models, can be used for prediction of the Flotation response. Both coal samples had the very similar amount and type of impurities as confirmed by XRD. FTIR, contact angle, zeta potential and SEM measurements were used to study the coal surface properties. It was found that the meta-bituminous coal was significantly more hydrophobic than the sub-bituminous coal and the coal surface roughness was significantly more pronounced in the case of the sub-bituminous coal than that in the case of the meta-bituminous coal. For these reasons, the recovery of the meta-bituminous coal by Flotation was dramatically higher than that of the sub-bituminous coal even in the presence of collector. Six Flotation kinetic models successfully predicted the Flotation data. Nevertheless, the modified first-order model was the only model that can be used to explain the Flotation responses under a wide range of the experimental conditions. The reason is that for most Flotation kinetic models, used in this study, particularly in the case of the sub-bituminous coal, the Flotation rate constants decreased with increasing in collector dosage while the opposite is true in the case of the Flotation recoveries.