Dépouillements

Calcination of low-grade laterite for concentration of Ni by magnetic separation / Jungah Kim in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 282–288 Titre : Calcination of low-grade laterite for concentration of Ni by magnetic separation Type de document : texte imprimé Auteurs : Jungah Kim, Auteur ; Gjergj Dodbiba, Auteur ; Hideaki Tanno, Auteur Année de publication : 2011 Article en page(s) : pp. 282–288 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Laterite  ore  Nickel  Magnetic  separation  Calcination  Magnetite  Hematite Résumé : With the continuous depletion of high-grade nickel ores such as millerite and niccolite, nickeliferous laterites have become the major source for the production of nickel metal. However, only 42% of the world’s production of nickel comes from laterites, since the concentration of Ni is relatively low (ca. 2 wt.%). In addition, other metals, such as magnesium, iron and silicon can be found in laterite, which make the concentration of nickel even more difficult. In this study, a low-grade nickeliferous laterite ore was first calcinated and then processed by using a wet magnetic separator in order to recover nickel. Since, the ore contains both Ni and Fe, the calcination of laterite is effective in altering the crystalline structure of Fe species and therefore its magnetic properties, which in turn enable the selective concentration of nickel by magnetic separation that is an easy and environmentally-friendly technique. The experimental results have indicated the importance of carefully controlling: (1) the calcination temperature; (2) the pulp density and (3) applied magnetic field strength. The main finding of this work was that magnetic separation is effective in recovering 48% of nickel from laterite, increasing the Ni grade in the recovered product from 1.5% to 2.9%, when prior to the separation the ore was calcinated at 500 °C for 1 h. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000063 [article] Calcination of low-grade laterite for concentration of Ni by magnetic separation [texte imprimé] / Jungah Kim, Auteur ; Gjergj Dodbiba, Auteur ; Hideaki Tanno, Auteur . - 2011 . - pp. 282–288. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 282–288 Mots-clés : Laterite  ore  Nickel  Magnetic  separation  Calcination  Magnetite  Hematite Résumé : With the continuous depletion of high-grade nickel ores such as millerite and niccolite, nickeliferous laterites have become the major source for the production of nickel metal. However, only 42% of the world’s production of nickel comes from laterites, since the concentration of Ni is relatively low (ca. 2 wt.%). In addition, other metals, such as magnesium, iron and silicon can be found in laterite, which make the concentration of nickel even more difficult. In this study, a low-grade nickeliferous laterite ore was first calcinated and then processed by using a wet magnetic separator in order to recover nickel. Since, the ore contains both Ni and Fe, the calcination of laterite is effective in altering the crystalline structure of Fe species and therefore its magnetic properties, which in turn enable the selective concentration of nickel by magnetic separation that is an easy and environmentally-friendly technique. The experimental results have indicated the importance of carefully controlling: (1) the calcination temperature; (2) the pulp density and (3) applied magnetic field strength. The main finding of this work was that magnetic separation is effective in recovering 48% of nickel from laterite, increasing the Ni grade in the recovered product from 1.5% to 2.9%, when prior to the separation the ore was calcinated at 500 °C for 1 h. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000063

Mechanism of hydrocyclone separation with water injection / J. Dueck in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 289–294 Titre : Mechanism of hydrocyclone separation with water injection Type de document : texte imprimé Auteurs : J. Dueck, Auteur ; E. Pikushchak, Auteur ; L. Minkov, Auteur Année de publication : 2011 Article en page(s) : pp. 289–294 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Hydrocyclones  Classification  Fine  particle  processing  Water  injection Résumé : In hydrocyclones, the particle separation efficiency is limited by the suspended fine particles, which are discharged with the coarse product in the underflow. It is well known that injecting water in the conical part of the cyclone reduces the fine particle fraction in the underflow. This paper presents a mathematical model that simulates the water injection in the conical component. The model accounts for the fluid flow and the particle motion. The stationary concentration distributions result from superpositioning the turbulent particle diffusion and particle settling. Particle interaction, due to hindered settling caused by increased density and viscosity of the suspension, and fine particle entrainment by settling coarse particles are included in the model. Water injection in the conical part of the hydrocyclone is performed to reduce fine particle discharge in the underflow. This added water transports the fine particles of the sediment to the center, where they are directed to the overflow. The model demonstrates the impact of the injection rate, injection velocity, and injection location on the shape of the partition curve. Under optimal conditions, the so-called “fish hook” of the curve is reduced without changing the cut size. The simulations are compared with experimental data of a 50-mm cyclone. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000038 [article] Mechanism of hydrocyclone separation with water injection [texte imprimé] / J. Dueck, Auteur ; E. Pikushchak, Auteur ; L. Minkov, Auteur . - 2011 . - pp. 289–294. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 289–294 Mots-clés : Hydrocyclones  Classification  Fine  particle  processing  Water  injection Résumé : In hydrocyclones, the particle separation efficiency is limited by the suspended fine particles, which are discharged with the coarse product in the underflow. It is well known that injecting water in the conical part of the cyclone reduces the fine particle fraction in the underflow. This paper presents a mathematical model that simulates the water injection in the conical component. The model accounts for the fluid flow and the particle motion. The stationary concentration distributions result from superpositioning the turbulent particle diffusion and particle settling. Particle interaction, due to hindered settling caused by increased density and viscosity of the suspension, and fine particle entrainment by settling coarse particles are included in the model. Water injection in the conical part of the hydrocyclone is performed to reduce fine particle discharge in the underflow. This added water transports the fine particles of the sediment to the center, where they are directed to the overflow. The model demonstrates the impact of the injection rate, injection velocity, and injection location on the shape of the partition curve. Under optimal conditions, the so-called “fish hook” of the curve is reduced without changing the cut size. The simulations are compared with experimental data of a 50-mm cyclone. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000038

Flow conditions in the air core of the hydrocyclone / M.A. Hararah in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 295–300 Titre : Flow conditions in the air core of the hydrocyclone Type de document : texte imprimé Auteurs : M.A. Hararah, Auteur ; E. Endres, Auteur ; J. Dueck, Auteur Année de publication : 2011 Article en page(s) : pp. 295–300 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Hydrocyclone  Classification  Fine  particle  processing  Modelling Résumé : The geometry and movement of the air core are sensitive indicators of the operational state of hydrocyclones. Therefore, an increased knowledge of the air core behaviour is desirable. Measurements of the air-core diameter in transparent hydrocyclones operated with a suspension of glass spheres are presented. The experiments indicate the dependencies between feed-solids content, air-core diameter, and spray angle of the underflow. Additionally, the air flow inside the air core in a transparent 50 mm water cyclone was experimentally investigated. Visualization techniques show the whirling motion of the air-core flow that is driven by the rotating liquid boundary of the air core. The radial distribution of the tangential air velocity was determined. The mean axial air velocity was shown to be dependent on the pressure drop and the hydrocyclone geometry. At the overflow discharge the air core is dispersed, and forms an aero suspension. Thus, the paper presents new aspects of the complex multi-phase flow in the hydrocyclone considering the gaseous phase. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509003227 [article] Flow conditions in the air core of the hydrocyclone [texte imprimé] / M.A. Hararah, Auteur ; E. Endres, Auteur ; J. Dueck, Auteur . - 2011 . - pp. 295–300. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 295–300 Mots-clés : Hydrocyclone  Classification  Fine  particle  processing  Modelling Résumé : The geometry and movement of the air core are sensitive indicators of the operational state of hydrocyclones. Therefore, an increased knowledge of the air core behaviour is desirable. Measurements of the air-core diameter in transparent hydrocyclones operated with a suspension of glass spheres are presented. The experiments indicate the dependencies between feed-solids content, air-core diameter, and spray angle of the underflow. Additionally, the air flow inside the air core in a transparent 50 mm water cyclone was experimentally investigated. Visualization techniques show the whirling motion of the air-core flow that is driven by the rotating liquid boundary of the air core. The radial distribution of the tangential air velocity was determined. The mean axial air velocity was shown to be dependent on the pressure drop and the hydrocyclone geometry. At the overflow discharge the air core is dispersed, and forms an aero suspension. Thus, the paper presents new aspects of the complex multi-phase flow in the hydrocyclone considering the gaseous phase. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509003227

Numerical simulation of the in-line pressure jig unit in coal preparation / K. J. Dong in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 301–312 Titre : Numerical simulation of the in-line pressure jig unit in coal preparation Type de document : texte imprimé Auteurs : K. J. Dong, Auteur ; S. B. Kuang, Auteur ; A. Vince, Auteur Année de publication : 2011 Article en page(s) : pp. 301–312 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Gravity  concentration  Classification  Coal  Computational  fluid  dynamics  Discrete  element  method Résumé : This paper presents a numerical study of the multiphase flow in an in-line pressure jig (IPJ), which is a high yield and high recovery gravity separation device widely used in ore processing but may have potential in coal preparation. The mathematical model is developed by use of the combined approach of computational fluid dynamics (CFD) for liquid flow and discrete element method (DEM) for particle flow. It is qualitatively verified by comparing the calculated and measured results under similar conditions. The effects of a few key variables, such as vibration frequency and amplitude, and the size and density of ragging particles, on the flow and separation performance of the IPJ are studied by conducting a series of simulations. The results are analyzed in terms of velocity field, porosity distribution and forces on particles. The findings would be helpful in the design, control and optimisation of an IPJ unit. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002635 [article] Numerical simulation of the in-line pressure jig unit in coal preparation [texte imprimé] / K. J. Dong, Auteur ; S. B. Kuang, Auteur ; A. Vince, Auteur . - 2011 . - pp. 301–312. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 301–312 Mots-clés : Gravity  concentration  Classification  Coal  Computational  fluid  dynamics  Discrete  element  method Résumé : This paper presents a numerical study of the multiphase flow in an in-line pressure jig (IPJ), which is a high yield and high recovery gravity separation device widely used in ore processing but may have potential in coal preparation. The mathematical model is developed by use of the combined approach of computational fluid dynamics (CFD) for liquid flow and discrete element method (DEM) for particle flow. It is qualitatively verified by comparing the calculated and measured results under similar conditions. The effects of a few key variables, such as vibration frequency and amplitude, and the size and density of ragging particles, on the flow and separation performance of the IPJ are studied by conducting a series of simulations. The results are analyzed in terms of velocity field, porosity distribution and forces on particles. The findings would be helpful in the design, control and optimisation of an IPJ unit. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002635

Fluid dynamics based modelling of the Falcon concentrator for ultrafine particle beneficiation / Jean-Sébastien Kroll-Rabotin in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 313–320 Titre : Fluid dynamics based modelling of the Falcon concentrator for ultrafine particle beneficiation Type de document : texte imprimé Auteurs : Jean-Sébastien Kroll-Rabotin, Auteur ; Florent Bourgeois, Auteur ; Éric Climent, Auteur Année de publication : 2011 Article en page(s) : pp. 313–320 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Gravity  concentration  Computational  fluid  dynamics  Modelling  Particle  size Résumé : Enhanced gravity separators are widely used in mineral beneficiation, as their superior gravity field enables them to separate particles within narrow classes of density and size. This study aims to shed light on the Falcon concentrator’s ability to separate particles within size and density ranges lower than usual, say 5–60 μm and 1.2–3.0 s.g. respectively. As differential particle settling is expected to be the prevailing separation mechanism under such conditions, this study presents the workings of a predictive Falcon separation model that embeds phenomenological fluid and particle flow simulation inside the Falcon’s flowing film. Adding to the novelty of modelling the Falcon concentrator using a fluid mechanics approach, one point of practical significance within this work is the derivation of the Falcon’s partition function from fluid flow simulation results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002556 [article] Fluid dynamics based modelling of the Falcon concentrator for ultrafine particle beneficiation [texte imprimé] / Jean-Sébastien Kroll-Rabotin, Auteur ; Florent Bourgeois, Auteur ; Éric Climent, Auteur . - 2011 . - pp. 313–320. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 313–320 Mots-clés : Gravity  concentration  Computational  fluid  dynamics  Modelling  Particle  size Résumé : Enhanced gravity separators are widely used in mineral beneficiation, as their superior gravity field enables them to separate particles within narrow classes of density and size. This study aims to shed light on the Falcon concentrator’s ability to separate particles within size and density ranges lower than usual, say 5–60 μm and 1.2–3.0 s.g. respectively. As differential particle settling is expected to be the prevailing separation mechanism under such conditions, this study presents the workings of a predictive Falcon separation model that embeds phenomenological fluid and particle flow simulation inside the Falcon’s flowing film. Adding to the novelty of modelling the Falcon concentrator using a fluid mechanics approach, one point of practical significance within this work is the derivation of the Falcon’s partition function from fluid flow simulation results. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002556

Controlled wash water injection to the hydrocyclone underflow / M.G. Farghaly in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 321–325 Titre : Controlled wash water injection to the hydrocyclone underflow Type de document : texte imprimé Auteurs : M.G. Farghaly, Auteur ; V. Golyk, Auteur ; G.A. Ibrahim, Auteur Année de publication : 2011 Article en page(s) : pp. 321–325 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Hydrocyclone  Fines  Controlled  water  injection Résumé : In hydrocyclones, the classification efficiency is limited by the fines, which are discharged together with the water in the underflow. It is well known that the injection of water in the conical portion of the cyclone reduces the fines in the underflow. This paper presents an improved technique, which is done via an injection at the upper end of the apex or the conical end. This results in a greater washing effect and reduced consumption of wash water. The process is stabilized by controlled water injection specific to the underflow shape. This controlled wash water injection is applied to kaolin processing for the reduction of kaolin losses in the cyclone underflow. A series of tests using 50-mm cyclones was conducted in this work, which demonstrates the marked improvement of the partition curves using controlled water injection. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002465 [article] Controlled wash water injection to the hydrocyclone underflow [texte imprimé] / M.G. Farghaly, Auteur ; V. Golyk, Auteur ; G.A. Ibrahim, Auteur . - 2011 . - pp. 321–325. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 321–325 Mots-clés : Hydrocyclone  Fines  Controlled  water  injection Résumé : In hydrocyclones, the classification efficiency is limited by the fines, which are discharged together with the water in the underflow. It is well known that the injection of water in the conical portion of the cyclone reduces the fines in the underflow. This paper presents an improved technique, which is done via an injection at the upper end of the apex or the conical end. This results in a greater washing effect and reduced consumption of wash water. The process is stabilized by controlled water injection specific to the underflow shape. This controlled wash water injection is applied to kaolin processing for the reduction of kaolin losses in the cyclone underflow. A series of tests using 50-mm cyclones was conducted in this work, which demonstrates the marked improvement of the partition curves using controlled water injection. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002465

Application of closely spaced inclined channels in gravity separation of fine particles / K. P. Galvin in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 326–338 Titre : Application of closely spaced inclined channels in gravity separation of fine particles Type de document : texte imprimé Auteurs : K. P. Galvin, Auteur ; J. Zhou, Auteur ; K. Walton, Auteur Année de publication : 2011 Article en page(s) : pp. 326–338 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Coal  Gravity  concentration  Elutriation  Oxide  ores  Gold  ores Résumé : This paper is concerned with the gravity separation of fine particles in a Reflux Classifier, a fluidized bed device with a system of parallel inclined channels located above. A significant advance is reported here over what was previously possible, through the application of a recent discovery described by Galvin et al. (2009). By using closely spaced inclined channels it is possible to achieve significant suppression of the effects of particle size, and hence produce a powerful separation on the basis of density. Experimental work was undertaken on the continuous steady state separation of coal and mineral matter, with a very narrow channel spacing of 1.77 mm used to process a feed finer than 0.5 mm in diameter, and a channel spacing of 4.2 mm used to process coarser feeds finer than 2.0 mm. These results are compared with previous findings reported in the literature for wider channels. The gravity separation performance is shown to be remarkably high, with a significant reduction in the variation of the separation density with particle size, and a significant reduction in the Ecart probable error, Ep. For example, over the particle size range 0.25–2.0 mm the composite Ep for the size range decreased from 0.14 for the wide channels used in previous studies to a typical level of 0.06 for the closely spaced inclined channels used in the present study. The separation performance was also shown to be insensitive to feed pulp density and feed solids throughput over a very broad range. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002404 [article] Application of closely spaced inclined channels in gravity separation of fine particles [texte imprimé] / K. P. Galvin, Auteur ; J. Zhou, Auteur ; K. Walton, Auteur . - 2011 . - pp. 326–338. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 326–338 Mots-clés : Coal  Gravity  concentration  Elutriation  Oxide  ores  Gold  ores Résumé : This paper is concerned with the gravity separation of fine particles in a Reflux Classifier, a fluidized bed device with a system of parallel inclined channels located above. A significant advance is reported here over what was previously possible, through the application of a recent discovery described by Galvin et al. (2009). By using closely spaced inclined channels it is possible to achieve significant suppression of the effects of particle size, and hence produce a powerful separation on the basis of density. Experimental work was undertaken on the continuous steady state separation of coal and mineral matter, with a very narrow channel spacing of 1.77 mm used to process a feed finer than 0.5 mm in diameter, and a channel spacing of 4.2 mm used to process coarser feeds finer than 2.0 mm. These results are compared with previous findings reported in the literature for wider channels. The gravity separation performance is shown to be remarkably high, with a significant reduction in the variation of the separation density with particle size, and a significant reduction in the Ecart probable error, Ep. For example, over the particle size range 0.25–2.0 mm the composite Ep for the size range decreased from 0.14 for the wide channels used in previous studies to a typical level of 0.06 for the closely spaced inclined channels used in the present study. The separation performance was also shown to be insensitive to feed pulp density and feed solids throughput over a very broad range. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002404

Gravity separation of coarse particles using the Reflux Classifier / K. P. Galvin in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 339–349 Titre : Gravity separation of coarse particles using the Reflux Classifier Type de document : texte imprimé Auteurs : K. P. Galvin, Auteur ; A.M. Callen, Auteur ; S. Spear, Auteur Année de publication : 2011 Article en page(s) : pp. 339–349 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Coal  preparation  Gravity  concentration  Separation  Fluidization  Particle  Sedimentation  Inclined  sedimentation  Coal  Elutriation  Oxide  ores  Diamonds Résumé : A comprehensive study examining the potential of the Reflux Classifier to be applied to the beneficiation of coarser coal up to 8 mm in size was undertaken. It was demonstrated that efficient combustible recovery and control of the separation density to target low ash products could be achieved. The major finding from the study was the critical importance of providing sufficient fluidization water, though beyond the critical level the process was largely insensitive to the fluidization rate. It was concluded the required fluidization velocity is nominally 10 m/h per mm of top-size, hence for a nominal 4 mm top size the required velocity is 40 m/h. In an extended campaign the control of the process was investigated by varying the set point density from high to low levels and then returning the process to the original settings, and demonstrating a return to the original separation. Further analysis was conducted to determine the partition curves and the shift in the separation density with particle size. The variation in the D50 with particle size approaches a level that is independent of the particle size. Previous data ( [Galvin et al., 2002] and [Galvin et al., 2004]) covering particles up to 2 mm in size are consistent with the results from this study, involving feeds with top sizes of 4 mm and 8 mm. Beyond a particle size of 2 mm the Ep is typically less than 0.05 and approaches about 0.03 as the particle size increases to 8 mm. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002398 [article] Gravity separation of coarse particles using the Reflux Classifier [texte imprimé] / K. P. Galvin, Auteur ; A.M. Callen, Auteur ; S. Spear, Auteur . - 2011 . - pp. 339–349. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 339–349 Mots-clés : Coal  preparation  Gravity  concentration  Separation  Fluidization  Particle  Sedimentation  Inclined  sedimentation  Coal  Elutriation  Oxide  ores  Diamonds Résumé : A comprehensive study examining the potential of the Reflux Classifier to be applied to the beneficiation of coarser coal up to 8 mm in size was undertaken. It was demonstrated that efficient combustible recovery and control of the separation density to target low ash products could be achieved. The major finding from the study was the critical importance of providing sufficient fluidization water, though beyond the critical level the process was largely insensitive to the fluidization rate. It was concluded the required fluidization velocity is nominally 10 m/h per mm of top-size, hence for a nominal 4 mm top size the required velocity is 40 m/h. In an extended campaign the control of the process was investigated by varying the set point density from high to low levels and then returning the process to the original settings, and demonstrating a return to the original separation. Further analysis was conducted to determine the partition curves and the shift in the separation density with particle size. The variation in the D50 with particle size approaches a level that is independent of the particle size. Previous data ( [Galvin et al., 2002] and [Galvin et al., 2004]) covering particles up to 2 mm in size are consistent with the results from this study, involving feeds with top sizes of 4 mm and 8 mm. Beyond a particle size of 2 mm the Ep is typically less than 0.05 and approaches about 0.03 as the particle size increases to 8 mm. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002398

Application of dielectrophoresis for the separation of minerals / G. R. Ballantyne in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 350–358 Titre : Application of dielectrophoresis for the separation of minerals Type de document : texte imprimé Auteurs : G. R. Ballantyne, Auteur ; P.N. Holtham, Auteur Année de publication : 2011 Article en page(s) : pp. 350–358 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulphide  ores  Electrostatic  separation  Sorting  methods  Mineral  processing Résumé : Comminution is an energy intensive process, accounting for approximately 29% of total mining energy (Tromans, 2008). Better liberation at coarser size ranges (0.5–2 mm) has been identified by the minerals industry as an opportunity for energy conservation. In order to capitalise on future developments in comminution, an effective coarse particle separation method is required for liberated particles which are too coarse for flotation. This paper reviews the application of dielectrophoresis as a potential technique for the removal of coarse liberated gangue, thereby significantly reducing the volume of ore continuing onto fine grinding. Dielectrophoresis is the translational motion of neutral matter caused by polarisation effects in a non-uniform electric field. A simple apparatus has been constructed, in which the deflection of a particle in a non-uniform electrical field is used to quantitatively measure the dielectrophoretic force on quartz and galena particles of various sizes. The results show that the force increases as a function of voltage squared and particle radius cubed. This technique can potentially be used to measure the effective permittivity of single mineral particles and quantify the effect of particle composition on separation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900226X [article] Application of dielectrophoresis for the separation of minerals [texte imprimé] / G. R. Ballantyne, Auteur ; P.N. Holtham, Auteur . - 2011 . - pp. 350–358. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 350–358 Mots-clés : Sulphide  ores  Electrostatic  separation  Sorting  methods  Mineral  processing Résumé : Comminution is an energy intensive process, accounting for approximately 29% of total mining energy (Tromans, 2008). Better liberation at coarser size ranges (0.5–2 mm) has been identified by the minerals industry as an opportunity for energy conservation. In order to capitalise on future developments in comminution, an effective coarse particle separation method is required for liberated particles which are too coarse for flotation. This paper reviews the application of dielectrophoresis as a potential technique for the removal of coarse liberated gangue, thereby significantly reducing the volume of ore continuing onto fine grinding. Dielectrophoresis is the translational motion of neutral matter caused by polarisation effects in a non-uniform electric field. A simple apparatus has been constructed, in which the deflection of a particle in a non-uniform electrical field is used to quantitatively measure the dielectrophoretic force on quartz and galena particles of various sizes. The results show that the force increases as a function of voltage squared and particle radius cubed. This technique can potentially be used to measure the effective permittivity of single mineral particles and quantify the effect of particle composition on separation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900226X

Characterizing hydrocyclone performance for grit removal from wastewater treatment activated sludge plants / Majdala Mansour-Geoffrion in Minerals engineering, Vol. 23 N° 4 (Mars 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 359–364 Titre : Characterizing hydrocyclone performance for grit removal from wastewater treatment activated sludge plants Type de document : texte imprimé Auteurs : Majdala Mansour-Geoffrion, Auteur ; Peter L. Dold, Auteur ; Daniel Lamarre, Auteur Année de publication : 2011 Article en page(s) : pp. 359–364 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Environmental  Hydrocyclones  Modelling  Pollution Résumé : Typically, 15–45% of the mixed liquor (sludge) in biological wastewater treatment plants (WWTPs) consists of inorganic (fixed) suspended solids. A portion of these inorganic compounds is grit (sand) originating from the influent. Grit accumulation impacts WWTP design and operating costs as these unbiodegradable solids reduce the effective treatment capacity of the bioreactor and other unit operations that must be sized to carry this material. The goal of this study was to characterize the performance of a hydrocyclone to selectively separate grit from activated sludge. Laboratory experiments were conducted with a 13 mm diameter Krebs hydrocyclone treating sludge from eight WWTPs. Reduced efficiencies of 17 ± 7% on fixed suspended solids and 9 ± 6% on volatile suspended solids were obtained. Grade efficiency curves enabled the development of a modified definition for cut size useful for this application. The characterization of hydrocyclone performance for grit removal from activated sludge will enable modelling of the process for integration into wastewater treatment simulators used for process performance prediction and design. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001903 [article] Characterizing hydrocyclone performance for grit removal from wastewater treatment activated sludge plants [texte imprimé] / Majdala Mansour-Geoffrion, Auteur ; Peter L. Dold, Auteur ; Daniel Lamarre, Auteur . - 2011 . - pp. 359–364. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 4 (Mars 2010) . - pp. 359–364 Mots-clés : Environmental  Hydrocyclones  Modelling  Pollution Résumé : Typically, 15–45% of the mixed liquor (sludge) in biological wastewater treatment plants (WWTPs) consists of inorganic (fixed) suspended solids. A portion of these inorganic compounds is grit (sand) originating from the influent. Grit accumulation impacts WWTP design and operating costs as these unbiodegradable solids reduce the effective treatment capacity of the bioreactor and other unit operations that must be sized to carry this material. The goal of this study was to characterize the performance of a hydrocyclone to selectively separate grit from activated sludge. Laboratory experiments were conducted with a 13 mm diameter Krebs hydrocyclone treating sludge from eight WWTPs. Reduced efficiencies of 17 ± 7% on fixed suspended solids and 9 ± 6% on volatile suspended solids were obtained. Grade efficiency curves enabled the development of a modified definition for cut size useful for this application. The characterization of hydrocyclone performance for grit removal from activated sludge will enable modelling of the process for integration into wastewater treatment simulators used for process performance prediction and design. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001903

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