According to the recently developed single-trough floating machine with the world's largest volume(inflatable mechanical agitation flotation machine with volume of 320 m3) in China, the gas-fluid two-phase flow in...According to the recently developed single-trough floating machine with the world's largest volume(inflatable mechanical agitation flotation machine with volume of 320 m3) in China, the gas-fluid two-phase flow in flotation cell was simulated using computational fluid dynamics method. It is shown that hexahedral mesh scheme is more suitable for the complex structure of the flotation cell than tetrahedral mesh scheme, and a mesh quality ranging from 0.7 to 1.0 is obtained. Comparative studies of the standard k-ε, k-ω and realizable k-ε turbulence models were carried out. It is indicated that the standard k-ε turbulence model could give a result relatively close to the practice and the liquid phase flow field is well characterized. In addition, two obvious recirculation zones are formed in the mixing zones, and the pressure on the rotor and stator is well characterized. Furthermore, the simulation results using improved standard k-ε turbulence model show that surface tension coefficient of 0.072, drag model of Grace and coefficient of 4, and lift coefficient of 0.001 can be achieved. The research results suggest that gas-fluid two-phase flow in large flotation cell can be well simulated using computational fluid dynamics method.展开更多
A rate equation of small particle-air bubble attachment in the turbulent now of flotation cells has beenderived. The equation, integrating both the collision probability and adhesion probability together, represents t...A rate equation of small particle-air bubble attachment in the turbulent now of flotation cells has beenderived. The equation, integrating both the collision probability and adhesion probability together, represents theprobability of attachment between particle and bubble in the turbulent flow. 'Capture efficiency' f(a) is introducedinto the rate equation to reflect the influence of energy hairier on the attachment rate. Three typical situations of particle-bubble interaction in flotation process have been discussed. For a completely hydrophobic particle-bubble system,f(a) = 1. This means that all collision leads to attachment. Whereas for hydrophilic particle-bubble systems, .f(a) =0. Thus no adhesion of particle on bubble occurs at all. In real notation circumstances, however, there always existsa certain energy barrier between the particle and the bubble. Therefore, f(a) = 0～1. In such cases, not all collisionsresult in particle-bubble attachment.展开更多
Fine particle flotation has been one of the main problems in many mineral processing plants.The bubble particle collision rate is very low for fine particles,which reduces flotation efficiency.Also,the existence of sl...Fine particle flotation has been one of the main problems in many mineral processing plants.The bubble particle collision rate is very low for fine particles,which reduces flotation efficiency.Also,the existence of slimes is,generally,detrimental to the flotation process,affecting the selectivity and the quality of the concentrates.Besides,it causes an increase in reagents consumption.Hence,in most of processing plants,some of these particles are transmitted to the tailing ponds to reduce the effects of these problems and increase the selectivity of the process.Esfordi phosphate plant in Iran loses more than 30%of its capacity as particles with d 80 finer than 30μm.These fine particles with 15.9%P_(2)O_(5)content are transferred to tailing dam.Processing of fine particles is very important for phosphate industry from economic and environmental aspects.This study addressed the processing of fine tailings(slimes)from a phosphate ore concentrator via flotation,despite the traditional view that ultrafine particles do not float.Phosphate flotation performances in the presence and absence of nanobubbles(NBs)in both mechanical and column cells were compared according to the metallurgical results of the process.NBs(generated by hydrodynamic cavitation)have interesting and exclusive properties such as high stability,durability and high surface area per volume,leading to increase of their utilization in mining-metallurgy and environmental areas.The results of this study revealed that,in the absence of NBs,a concentrate containing 26.9%P_(2)O_(5)with a recovery of 29.13%was obtained using mechanical cells in comparison to 31.6%P_(2)O_(5)with a recovery of 32.74%obtained using column flotation.In the presence of NBs,the recoveries of the concentrate of the mechanical and column flotation increased to 40.49%and 41.26%with 28.47%and 30.43%P_(2)O_(5)contents,respectively.Comparative study showed that the column flotation was almost more efficient for processing the phosphate ore in the presence of the NBs,and had thicker froth layer compared to the mechanical flotation.展开更多
The cyclonic-static micro-bubble flotation column （FCSMC） is a highly efficient mineral processing equipment. In this study, a cell-column （FCSMC） integration process was investigated for the separation of bauxite...The cyclonic-static micro-bubble flotation column （FCSMC） is a highly efficient mineral processing equipment. In this study, a cell-column （FCSMC） integration process was investigated for the separation of bauxite and its feasibility was analyzed on a theoretical basis The properties of low-grade bauxite ore from Henan Province, China were analyzed. Parameters such as reagent dosage, scraping bubble time, and pressure of the circulating pump during the sorting process were investigated and optimized to improve the flotation efficiency. On the basis of these parameters, continuous separation experiments were conducted. Bauxite concentrate with an aluminum-to-silicon （A/S） mass ratio of 6.37 and a 77.63wt% recovery rate were achieved via a flow sheet consisting of ＂fast flotation using a flotation cell, one roughing flotation and one cleaning flotation using flotation columns＂. Compared with the full-flotation-cells process, the cell-column integration process resulted in an increase of the A/S ratio by 0.41 and the recovery rate by 17.58wt%. Cell-coltmm integration separation technology represents a new approach for the separation of middle-to-low-grade bauxite ore.展开更多
基金Project(51074027)supported by the National Natural Science Foundation of China
文摘According to the recently developed single-trough floating machine with the world's largest volume(inflatable mechanical agitation flotation machine with volume of 320 m3) in China, the gas-fluid two-phase flow in flotation cell was simulated using computational fluid dynamics method. It is shown that hexahedral mesh scheme is more suitable for the complex structure of the flotation cell than tetrahedral mesh scheme, and a mesh quality ranging from 0.7 to 1.0 is obtained. Comparative studies of the standard k-ε, k-ω and realizable k-ε turbulence models were carried out. It is indicated that the standard k-ε turbulence model could give a result relatively close to the practice and the liquid phase flow field is well characterized. In addition, two obvious recirculation zones are formed in the mixing zones, and the pressure on the rotor and stator is well characterized. Furthermore, the simulation results using improved standard k-ε turbulence model show that surface tension coefficient of 0.072, drag model of Grace and coefficient of 4, and lift coefficient of 0.001 can be achieved. The research results suggest that gas-fluid two-phase flow in large flotation cell can be well simulated using computational fluid dynamics method.
文摘A rate equation of small particle-air bubble attachment in the turbulent now of flotation cells has beenderived. The equation, integrating both the collision probability and adhesion probability together, represents theprobability of attachment between particle and bubble in the turbulent flow. 'Capture efficiency' f(a) is introducedinto the rate equation to reflect the influence of energy hairier on the attachment rate. Three typical situations of particle-bubble interaction in flotation process have been discussed. For a completely hydrophobic particle-bubble system,f(a) = 1. This means that all collision leads to attachment. Whereas for hydrophilic particle-bubble systems, .f(a) =0. Thus no adhesion of particle on bubble occurs at all. In real notation circumstances, however, there always existsa certain energy barrier between the particle and the bubble. Therefore, f(a) = 0～1. In such cases, not all collisionsresult in particle-bubble attachment.
基金Project supported by Iran Mineral Processing Research Center(IMPRC)。
文摘Fine particle flotation has been one of the main problems in many mineral processing plants.The bubble particle collision rate is very low for fine particles,which reduces flotation efficiency.Also,the existence of slimes is,generally,detrimental to the flotation process,affecting the selectivity and the quality of the concentrates.Besides,it causes an increase in reagents consumption.Hence,in most of processing plants,some of these particles are transmitted to the tailing ponds to reduce the effects of these problems and increase the selectivity of the process.Esfordi phosphate plant in Iran loses more than 30%of its capacity as particles with d 80 finer than 30μm.These fine particles with 15.9%P_(2)O_(5)content are transferred to tailing dam.Processing of fine particles is very important for phosphate industry from economic and environmental aspects.This study addressed the processing of fine tailings(slimes)from a phosphate ore concentrator via flotation,despite the traditional view that ultrafine particles do not float.Phosphate flotation performances in the presence and absence of nanobubbles(NBs)in both mechanical and column cells were compared according to the metallurgical results of the process.NBs(generated by hydrodynamic cavitation)have interesting and exclusive properties such as high stability,durability and high surface area per volume,leading to increase of their utilization in mining-metallurgy and environmental areas.The results of this study revealed that,in the absence of NBs,a concentrate containing 26.9%P_(2)O_(5)with a recovery of 29.13%was obtained using mechanical cells in comparison to 31.6%P_(2)O_(5)with a recovery of 32.74%obtained using column flotation.In the presence of NBs,the recoveries of the concentrate of the mechanical and column flotation increased to 40.49%and 41.26%with 28.47%and 30.43%P_(2)O_(5)contents,respectively.Comparative study showed that the column flotation was almost more efficient for processing the phosphate ore in the presence of the NBs,and had thicker froth layer compared to the mechanical flotation.
基金the National Natural Science Foundation of China (No. 51174205)the Program for New Century Excellent Talents in University (No. NCET-12-0962)+1 种基金the National Basic Research and Development Program of China (No. 2014CB238905)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The cyclonic-static micro-bubble flotation column （FCSMC） is a highly efficient mineral processing equipment. In this study, a cell-column （FCSMC） integration process was investigated for the separation of bauxite and its feasibility was analyzed on a theoretical basis The properties of low-grade bauxite ore from Henan Province, China were analyzed. Parameters such as reagent dosage, scraping bubble time, and pressure of the circulating pump during the sorting process were investigated and optimized to improve the flotation efficiency. On the basis of these parameters, continuous separation experiments were conducted. Bauxite concentrate with an aluminum-to-silicon （A/S） mass ratio of 6.37 and a 77.63wt% recovery rate were achieved via a flow sheet consisting of ＂fast flotation using a flotation cell, one roughing flotation and one cleaning flotation using flotation columns＂. Compared with the full-flotation-cells process, the cell-column integration process resulted in an increase of the A/S ratio by 0.41 and the recovery rate by 17.58wt%. Cell-coltmm integration separation technology represents a new approach for the separation of middle-to-low-grade bauxite ore.
