Particle-bubble interaction during electro-flotation of cassiterite was investigated by determining the recovery of cassiterite and the collision mechanism of cassiterite particle and H2 bubble. Flotation tests at dif...Particle-bubble interaction during electro-flotation of cassiterite was investigated by determining the recovery of cassiterite and the collision mechanism of cassiterite particle and H2 bubble. Flotation tests at different conditions were conducted in a single bubble flotation cell. The recovery of cassiterite was found to be affected by cassiterite particle and bubble size. A matching range, in which the best recovery can be obtained, was found between particle and bubble size. Collision, attachment, and detachment of the particle-bubble were observed and captured by a high-speed camera. Particle-bubble collision and attachment were analyzed with the use of particle-bubble interaction theory to obtain the experimental results. An attachment model was introduced and verified through the photos captured by the high-speed camera. A bridge role was observed between the bubbles and particles. Particle-bubble interaction was found to be affected by bubble size and particle size, which significantly influenced not only the collision and attachment behavior of the particles and bubbles but also the flotation recovery of fine cassiterite particles.展开更多
In order to discuss the particle-bubble interaction during the electro-flotation of cassiterite,the recovery of cassiterite with different particle sizes was investigated,and the collision mechanism between the cassit...In order to discuss the particle-bubble interaction during the electro-flotation of cassiterite,the recovery of cassiterite with different particle sizes was investigated,and the collision mechanism between the cassiterite particles and H2 bubbles was explored.The flotation tests were carried out in a single bubble flotation cell.The results show that cassiterite particles 10 μm,10-20 μm,20？38 μm and 38-74 μm match with bubbles with size of 50-150 μm,about 250 μm,74 μm and 74 μm,respectively,and a better recovery can be obtained.It is demonstrated that the recovery of cassiterite is influenced by the size of cassiterite particles and bubbles.Furthermore,the probabilities of collision,adhesion,detachment and collection were calculated using the collision,attachment and collection models.Theoretical calculation results show that the collision probability decreases sharply with decreasing particle size and increasing bubble size（below 150 μm）.The attachment probability would increase from the effective collision,leading to the increase of recovery.展开更多
The flotation of diasporic bauxite is to separate diaspore(valuable mineral)from aluminosilicate minerals(gangue minerals,mainly including kaolinite,illite and pyrophyllite),and the microscopic interaction force betwe...The flotation of diasporic bauxite is to separate diaspore(valuable mineral)from aluminosilicate minerals(gangue minerals,mainly including kaolinite,illite and pyrophyllite),and the microscopic interaction force between the two types of minerals and air bubbles determines the separation efficiency.In this paper,based on the extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory,the van der Waals,electrostatic and hydrophobic interaction between particles of the four minerals mentioned above and air bubbles in collectorless solution were calculated first,and then diaspore and kaolinite were taken as examples to analyze the influence of various factors such as electrolyte concentration,mineral particle size,air bubble size,collector type(dodecylamine hydrochloride(DAH)and sodium oleate(NaOL))and concentration,and pulp pH on the interactions between the particles of valuable mineral and gangue minerals and air bubbles.The results showed that the total extended DLVO interactions between the four minerals and air bubbles were repulsive in most cases in collectorless solution.The increase in electrolyte concentration reduced the interaction force or even changed the direction of the force under certain circumstances.The addition of DAH and NaOL can reduce the adhesion energy barrier of kaolinitebubble and diaspore-bubble respectively.Each type of minerals exhibited a specific interface interaction response with air bubbles in each collector with different pH values.The research results have theoretical guiding significance for the optimization and directional control of diasporic bauxite flotation conditions.展开更多
Smoothed particle hydrodynamics(SPH)is a Lagrangian,mesh-free numerical method renowned for its ability to handle fluid dynamics problems with large interface deformations and multiphase flow coupling.This study intro...Smoothed particle hydrodynamics(SPH)is a Lagrangian,mesh-free numerical method renowned for its ability to handle fluid dynamics problems with large interface deformations and multiphase flow coupling.This study introduces an SPH-based multiphase flow model for simulating bubbly flows involving various immiscible fluids.The model uses a volume-based density discretization equation,ensuring numerical accuracy near interfaces,independent of density ratios,thus maintaining accuracy and stability even at high density ratios.By integrating the Continuous Surface Force method for surface tension into the multiphase SPH model,the study simulates interfacial behavior between phases.The model accurately predicts Laplace pressure differences across interfaces,maintaining interface stability at density ratios up to 100.0.Simulations of single and double bubble ascents elucidate the influence of the Bond number on bubble shape,rising distance,and velocity.As the Bond number increases,bubbles flatten and develop tails,affecting their integrity.The study also simulates multiple bubbles ascents in water,showcasing the model's ability to capture complex interfacial behaviors in bubbly flows,including deformation,adsorption,coalescence,and tearing.展开更多
Vortex dynamics and wall shear stress induced by cavitation bubble oscillations under the influence of particles are numerically investigated with the aid of a compressible two-phase flow solver in OpenFOAM.The genera...Vortex dynamics and wall shear stress induced by cavitation bubble oscillations under the influence of particles are numerically investigated with the aid of a compressible two-phase flow solver in OpenFOAM.The generation,evolution,and disappearance of vortexes for three jet behaviors are discussed in detail.The variations of wall shear stress induced by the jets and the vortexes during the bubble oscillations are analyzed.Numerical results reveal that vortex dynamics is related to bubble evolution and jet behavior.After the jet pierces the bubble,an annular vortex with the bubble as the vortex core is generated by the bubble collapse.For the bubble that collapses near the wall,it generates multiple small vortexes near the wall and causes discontinuities in the wall shear stress.For the bubble that collapses away from the wall,it does not generate vortexes near the wall,and its oscillations cause the wall shear stress to vary periodically with different periods.In addition,the wall shear stress at the axis of symmetry increases abruptly when the jet hits the wall.展开更多
The presence of particles and the shock waves generated by the cavitation bubbles can significantly affect the safety and the performance of hydrodynamic machineries.In the present paper,the shock waves generated by c...The presence of particles and the shock waves generated by the cavitation bubbles can significantly affect the safety and the performance of hydrodynamic machineries.In the present paper,the shock waves generated by cavitation bubble collapsing near the particle are numerically investigated based on the OpenFOAM together with the numerical schlieren for the shock wave identifications.The numerical results reveal that the stand-off distance is one of the paramount factors affecting the interactions between the particle and the shock waves.Several different kinds of shock waves(e.g.,bubble-inception,jet formation,particle reflected and jet-split shock waves)are observed during the bubble collapsing near the particle.For stand-off distance smaller than 0.5 or larger than 1.1,the maximum pressure at particle surface generated by the bubble growth can surpass those of the collapse stage.展开更多
In this paper,the dynamic behaviors of the cavitation bubble near a fixed spherical particle during the second oscillation period are analyzed based on the high-speed photographic system.The deformation and motion of ...In this paper,the dynamic behaviors of the cavitation bubble near a fixed spherical particle during the second oscillation period are analyzed based on the high-speed photographic system.The deformation and motion of the bubble during the second period are investigated by changing the distance between the particle and the bubble and the maximum radius of the bubble.Meanwhile,the variation of the equivalent radius and the centroid motions are analyzed,and the dynamic behaviors of the bubble are categorized according to the bubble morphological characteristics during the second period.Through this research,it is found that(1)The dynamic behaviors of the bubble during the second oscillation period could be divided into three typical cases:For case 1,a bulge would exist on the bubble interface away from the particle,and for case 2,a bulge would appear on the bubble interface and evolve towards the particle,while for case 3,the bubble would be divided into two parts.(2)The larger the dimensionless distance between the particle and the bubble,the smaller the maximum bubble equivalent radius in the second period,and the shorter the second oscillation period.(3)When the bubble is close to the particle,a counter-jet appears at the bubble interface away from the particle during the rebound stage.展开更多
基金Project(50774094)supported by the National Natural Science Foundation of ChinaProject(2011BAB05B01)supported by the National Key Technology Research and Development Program of ChinaProject(2013M542076)supported by the Postdoctoral Science Foundation of China
文摘Particle-bubble interaction during electro-flotation of cassiterite was investigated by determining the recovery of cassiterite and the collision mechanism of cassiterite particle and H2 bubble. Flotation tests at different conditions were conducted in a single bubble flotation cell. The recovery of cassiterite was found to be affected by cassiterite particle and bubble size. A matching range, in which the best recovery can be obtained, was found between particle and bubble size. Collision, attachment, and detachment of the particle-bubble were observed and captured by a high-speed camera. Particle-bubble collision and attachment were analyzed with the use of particle-bubble interaction theory to obtain the experimental results. An attachment model was introduced and verified through the photos captured by the high-speed camera. A bridge role was observed between the bubbles and particles. Particle-bubble interaction was found to be affected by bubble size and particle size, which significantly influenced not only the collision and attachment behavior of the particles and bubbles but also the flotation recovery of fine cassiterite particles.
基金Project(50774094)supported by the National Natural Science Foundation of ChinaProject(2010CB630905)supported by the National Basic Research Program of China
文摘In order to discuss the particle-bubble interaction during the electro-flotation of cassiterite,the recovery of cassiterite with different particle sizes was investigated,and the collision mechanism between the cassiterite particles and H2 bubbles was explored.The flotation tests were carried out in a single bubble flotation cell.The results show that cassiterite particles 10 μm,10-20 μm,20？38 μm and 38-74 μm match with bubbles with size of 50-150 μm,about 250 μm,74 μm and 74 μm,respectively,and a better recovery can be obtained.It is demonstrated that the recovery of cassiterite is influenced by the size of cassiterite particles and bubbles.Furthermore,the probabilities of collision,adhesion,detachment and collection were calculated using the collision,attachment and collection models.Theoretical calculation results show that the collision probability decreases sharply with decreasing particle size and increasing bubble size（below 150 μm）.The attachment probability would increase from the effective collision,leading to the increase of recovery.
基金supported by the National Natural Science Foundation of China(No.51904240,51904239,52104268)the Natural Science Foundation of Shaanxi Province(No.2020JQ-752,2021JQ-571)+3 种基金the Postdoctoral Science Foundation of China(No.2019M653877XB)the Outstanding Youth Science Foundation of Xi’an University of Science and Technology(No.2019YQ3-08)the Huo Yingdong Education Foundation(No.171102)the 2019 Merit-based Science and Technology Project Foundation for Shannxi Overseas-educated Scholars(No.14).
文摘The flotation of diasporic bauxite is to separate diaspore(valuable mineral)from aluminosilicate minerals(gangue minerals,mainly including kaolinite,illite and pyrophyllite),and the microscopic interaction force between the two types of minerals and air bubbles determines the separation efficiency.In this paper,based on the extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory,the van der Waals,electrostatic and hydrophobic interaction between particles of the four minerals mentioned above and air bubbles in collectorless solution were calculated first,and then diaspore and kaolinite were taken as examples to analyze the influence of various factors such as electrolyte concentration,mineral particle size,air bubble size,collector type(dodecylamine hydrochloride(DAH)and sodium oleate(NaOL))and concentration,and pulp pH on the interactions between the particles of valuable mineral and gangue minerals and air bubbles.The results showed that the total extended DLVO interactions between the four minerals and air bubbles were repulsive in most cases in collectorless solution.The increase in electrolyte concentration reduced the interaction force or even changed the direction of the force under certain circumstances.The addition of DAH and NaOL can reduce the adhesion energy barrier of kaolinitebubble and diaspore-bubble respectively.Each type of minerals exhibited a specific interface interaction response with air bubbles in each collector with different pH values.The research results have theoretical guiding significance for the optimization and directional control of diasporic bauxite flotation conditions.
基金the State Key Laboratory of Intelligent Optimized Manufacturing in Mining&Metallurgy Process Open Research Fund(No.JTKY202404622)and(No.BGRIMM-KZSKL-2023-12).
文摘Smoothed particle hydrodynamics(SPH)is a Lagrangian,mesh-free numerical method renowned for its ability to handle fluid dynamics problems with large interface deformations and multiphase flow coupling.This study introduces an SPH-based multiphase flow model for simulating bubbly flows involving various immiscible fluids.The model uses a volume-based density discretization equation,ensuring numerical accuracy near interfaces,independent of density ratios,thus maintaining accuracy and stability even at high density ratios.By integrating the Continuous Surface Force method for surface tension into the multiphase SPH model,the study simulates interfacial behavior between phases.The model accurately predicts Laplace pressure differences across interfaces,maintaining interface stability at density ratios up to 100.0.Simulations of single and double bubble ascents elucidate the influence of the Bond number on bubble shape,rising distance,and velocity.As the Bond number increases,bubbles flatten and develop tails,affecting their integrity.The study also simulates multiple bubbles ascents in water,showcasing the model's ability to capture complex interfacial behaviors in bubbly flows,including deformation,adsorption,coalescence,and tearing.
基金Project supported by the National Natural Science Foundation of China(Grant No.51976056)。
文摘Vortex dynamics and wall shear stress induced by cavitation bubble oscillations under the influence of particles are numerically investigated with the aid of a compressible two-phase flow solver in OpenFOAM.The generation,evolution,and disappearance of vortexes for three jet behaviors are discussed in detail.The variations of wall shear stress induced by the jets and the vortexes during the bubble oscillations are analyzed.Numerical results reveal that vortex dynamics is related to bubble evolution and jet behavior.After the jet pierces the bubble,an annular vortex with the bubble as the vortex core is generated by the bubble collapse.For the bubble that collapses near the wall,it generates multiple small vortexes near the wall and causes discontinuities in the wall shear stress.For the bubble that collapses away from the wall,it does not generate vortexes near the wall,and its oscillations cause the wall shear stress to vary periodically with different periods.In addition,the wall shear stress at the axis of symmetry increases abruptly when the jet hits the wall.
基金Project supported by the National Natural Science Foundation of China (Grant No.51976056).
文摘The presence of particles and the shock waves generated by the cavitation bubbles can significantly affect the safety and the performance of hydrodynamic machineries.In the present paper,the shock waves generated by cavitation bubble collapsing near the particle are numerically investigated based on the OpenFOAM together with the numerical schlieren for the shock wave identifications.The numerical results reveal that the stand-off distance is one of the paramount factors affecting the interactions between the particle and the shock waves.Several different kinds of shock waves(e.g.,bubble-inception,jet formation,particle reflected and jet-split shock waves)are observed during the bubble collapsing near the particle.For stand-off distance smaller than 0.5 or larger than 1.1,the maximum pressure at particle surface generated by the bubble growth can surpass those of the collapse stage.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51976056,52076215).
文摘In this paper,the dynamic behaviors of the cavitation bubble near a fixed spherical particle during the second oscillation period are analyzed based on the high-speed photographic system.The deformation and motion of the bubble during the second period are investigated by changing the distance between the particle and the bubble and the maximum radius of the bubble.Meanwhile,the variation of the equivalent radius and the centroid motions are analyzed,and the dynamic behaviors of the bubble are categorized according to the bubble morphological characteristics during the second period.Through this research,it is found that(1)The dynamic behaviors of the bubble during the second oscillation period could be divided into three typical cases:For case 1,a bulge would exist on the bubble interface away from the particle,and for case 2,a bulge would appear on the bubble interface and evolve towards the particle,while for case 3,the bubble would be divided into two parts.(2)The larger the dimensionless distance between the particle and the bubble,the smaller the maximum bubble equivalent radius in the second period,and the shorter the second oscillation period.(3)When the bubble is close to the particle,a counter-jet appears at the bubble interface away from the particle during the rebound stage.
