Electromagnetic filtration of primary Fe-rich phases (complex compound of AlFeSiMn) from Al-Si alloy melt containing 1.2 wt pct Fe have been studied by theoretical analysis and on a self-designed electromagnetic filtr...Electromagnetic filtration of primary Fe-rich phases (complex compound of AlFeSiMn) from Al-Si alloy melt containing 1.2 wt pct Fe have been studied by theoretical analysis and on a self-designed electromagnetic filtration equipment. The principle of the electromagnetic filtration is that the EMF (electromagnetic force) scarcely acts on the primary Fe-rich phases having low electric conductivity, which are then moved in the direction opposite to that of the EMF. Experimental results show that the primary Fe-rich phases are separated from Al-Si alloy melt and are collected in the filter while the melt is in horizontal flow. The removal efficiency of the primary iron-phases (77) calculated is less as the greatest flow velocity of the melt (UM) and the height of the filter (2h) are larger, while it becomes larger as EMF, operating distance of electromagnetic force (cr) and particle size (dv) become larger. It has been confirmed that the primary iron-phases larger than 20 jim can be removed efficiently by theoretical analysis and experiments. This new technique is high efficient and available for continuously flowing melts as compared with natural settling and filtration methods, which offer a possibility for recycling high quality aluminum alloys.展开更多
The phase states of the catalytic system of FeCl3-Al（i-Bu）3-pyridine are studied in the paper by means of the Tyndall effect, electron microscopy and super-filtration. It is found that the catalyst dispersing in the...The phase states of the catalytic system of FeCl3-Al（i-Bu）3-pyridine are studied in the paper by means of the Tyndall effect, electron microscopy and super-filtration. It is found that the catalyst dispersing in the butadienehydrogasoline solution exists in small particles and the size of particle is 30 nm or so in diameter. The catalyst belongs to a multi-phase catalytic system. The active center of catalyst lies on the surface of nanometer particles, which are amorphous. The ratios of different components of catalyst affect the formation of the particles. With the optimum ratio, nanometer particles, which disperse more uniformly and are of highly catalytic activity, can be obtained.展开更多
Aqueous filtration systems with granular media are increasingly implemented as a unit operation for the treatment of urban waters.Many of these aqueous filtration systems are designed with coarse granular media and ar...Aqueous filtration systems with granular media are increasingly implemented as a unit operation for the treatment of urban waters.Many of these aqueous filtration systems are designed with coarse granular media and are therefore subject to finite granular Reynolds numbers(Reg).In contrast to the Reg conditions generated by such designs,current hydrosol filtration models,such as the Yao and RT models,rely on a flow solution that is derived within the Stokes limit at low Reg.In systems that are subject to these finite and higher Reg regimes,the collector efficiency has not been examined.Therefore,in this study,we develop a 3D periodic porosity-compensated face-centered cubic sphere(PCFCC)computational fluid dynamics(CFD)model,with the surface interactions incorporated,to investigate the collector efficiency for Reg ranging from 0.01 to 20.Particle filtration induced by interception and sedimentation is examined for non-Brownian particlesfanging from 1 to 100 μm under favorable surface interactions for particle adhesion.The results from the CFD-based PCFCC model agreed well with those of the classical RT and Yao models for Reg<1.Based on 3150 simulations from the PCFCC model,we developed a new correlation for vertical aqueous filtration based on a modified gravitation number,NG^*,for the initial deep-bed filtration efficiency at lower yet finite(0.01 to 20)Reg.The proposed PCFCC model has low computational cost and is extensibile from vertical to horizontal filtration at low and finite Reg.展开更多
基金This project was supported by the China PostdoctoralScience FOundation, the Research Fund for the DoctoralProgram of Higher Educ
文摘Electromagnetic filtration of primary Fe-rich phases (complex compound of AlFeSiMn) from Al-Si alloy melt containing 1.2 wt pct Fe have been studied by theoretical analysis and on a self-designed electromagnetic filtration equipment. The principle of the electromagnetic filtration is that the EMF (electromagnetic force) scarcely acts on the primary Fe-rich phases having low electric conductivity, which are then moved in the direction opposite to that of the EMF. Experimental results show that the primary Fe-rich phases are separated from Al-Si alloy melt and are collected in the filter while the melt is in horizontal flow. The removal efficiency of the primary iron-phases (77) calculated is less as the greatest flow velocity of the melt (UM) and the height of the filter (2h) are larger, while it becomes larger as EMF, operating distance of electromagnetic force (cr) and particle size (dv) become larger. It has been confirmed that the primary iron-phases larger than 20 jim can be removed efficiently by theoretical analysis and experiments. This new technique is high efficient and available for continuously flowing melts as compared with natural settling and filtration methods, which offer a possibility for recycling high quality aluminum alloys.
文摘The phase states of the catalytic system of FeCl3-Al（i-Bu）3-pyridine are studied in the paper by means of the Tyndall effect, electron microscopy and super-filtration. It is found that the catalyst dispersing in the butadienehydrogasoline solution exists in small particles and the size of particle is 30 nm or so in diameter. The catalyst belongs to a multi-phase catalytic system. The active center of catalyst lies on the surface of nanometer particles, which are amorphous. The ratios of different components of catalyst affect the formation of the particles. With the optimum ratio, nanometer particles, which disperse more uniformly and are of highly catalytic activity, can be obtained.
基金Funding was provided through the University of Florida Graduate School Fellowship.
文摘Aqueous filtration systems with granular media are increasingly implemented as a unit operation for the treatment of urban waters.Many of these aqueous filtration systems are designed with coarse granular media and are therefore subject to finite granular Reynolds numbers(Reg).In contrast to the Reg conditions generated by such designs,current hydrosol filtration models,such as the Yao and RT models,rely on a flow solution that is derived within the Stokes limit at low Reg.In systems that are subject to these finite and higher Reg regimes,the collector efficiency has not been examined.Therefore,in this study,we develop a 3D periodic porosity-compensated face-centered cubic sphere(PCFCC)computational fluid dynamics(CFD)model,with the surface interactions incorporated,to investigate the collector efficiency for Reg ranging from 0.01 to 20.Particle filtration induced by interception and sedimentation is examined for non-Brownian particlesfanging from 1 to 100 μm under favorable surface interactions for particle adhesion.The results from the CFD-based PCFCC model agreed well with those of the classical RT and Yao models for Reg<1.Based on 3150 simulations from the PCFCC model,we developed a new correlation for vertical aqueous filtration based on a modified gravitation number,NG^*,for the initial deep-bed filtration efficiency at lower yet finite(0.01 to 20)Reg.The proposed PCFCC model has low computational cost and is extensibile from vertical to horizontal filtration at low and finite Reg.
