Numerical Simulation And Experimental Research On The Capture Of Rotating Magnetic Media Filaments

China is rich in weak magnetic mineral resources,and high gradient magnetic separation is the key technology to develop this kind of mineral resources.However,its selectivity is low,and it is mainly used in the production of coarse selection and dredging.The new method of centrifugal high gradient magnetic separation adopts the new mode of dynamic capture of rotating magnetic wires.In this paper,a Cen Mag-100 centrifugal high gradient magnetic separator is used as the research object,and the new characteristics of magnetic wires captured by rotating magnetic wires are deeply studied by combining computer numerical simulation with experimental research.Firstly,the structure analysis and parameter measurement of the device were carried out,and the simulation two-dimensional physical model was established.Based on this model,analysis and research are carried out in the following aspects:(1)The magnetic field distribution of cenmag-100 centrifugal high gradient magnetic separator was analyzed and the magnetic field of the equipment was optimized and constructed.The feasible magnetic system structure was proposed and simulated.(2)The distribution characteristics of the flow field in the separation region during the capture of the rotating magnetic medium are analyzed.(3)The trajectory characteristics of the particles in the process of capture are analyzed.(4)On the basis of the above,the ilmenite capture test is carried out,the influence of test conditions on the rotating magnetic wire capture is analyzed,and the capture law is obtained.The numerical simulation study of rotating magnetic dielectric wire acquisition shows that:(1)In the sorting area of the equipment,the magnetic field is evenly distributed in the circumference with the center of the sorting area as the center.The closer to the outer boundary of the sorting area,the stronger the magnetic field is.The magnetic wire is magnetized in the background magnetic field,and the magnetization direction is along the magnetic field distribution direction.The surrounding magnetic field is higher than the background magnetic field in the range of 2.0-3.0 mm from the surface of the magnetic wire,and the maximum is 0.82 T.The results show that the magnetic field distribution of the cylindrical magnetic system is more uniform than that of the original permanent magnetic system,and the magnetic field intensity is almost the same everywhere in the separation region.(2)The fluid velocity in the separation zone increases with the increase of rotating speed and inlet velocity,and the larger the rotating speed is,the longer the flow path of the fluid in the separation zone is,and the larger the inlet velocity is,the shorter the flow path is.(3)The fluid velocity around the magnetic medium wire is distributed as the fluid velocity at both ends along the direction of motion of the medium wire is obviously larger than that at both sides of the direction of vertical motion,among which the fluid velocity at the surface of the water on the back of the magnetic medium wire is the largest,while that at the side of vertical motion near the center of rotation is the smallest.(4)The particle trajectory is related to the fluid force and magnetic force that the particle is subjected to,and the particle trajectory equation is derived based on the stress analysis,and the particle size,mass,initial velocity and fluid velocity are the important factors that affect the particle trajectory.(5)The effects of magnetic wire rotation speed and ore particle size on particle capture are obtained: the catch amount of magnetic medium single wire decreases with the increase of magnetic wire rotation speed,but increases with the increase of ore particle size.The results of ilmenite capture test show that:(1)According to the full-size capture test of ilmenite concentrate,the saturation ore feeding amount of magnetic wires is 190 g/time.The catch amount of the magnetic wire at different positions is slightly greater in the outer ring at low rotating speed than in the inner ring at high rotating speed.The catch amount of magnetic wire is related to the diameter and rotation speed of magnetic wire.In addition,with the increase of pulp flow,the catch has been on a downward trend,and the downward trend is more severe when the pulp flow is more than 6.5 L/min.(2)The results of the capture experiments of ilmenite concentrate with different grain sizes show that the catch amount of ilmenite concentrate with different grain sizes shows a rule that the bigger the grain size is,the bigger the catch amount is,and this rule is not affected by the speed,diameter and slurry flow of the magnetic wire.(3)According to the capture test of ilmenite concentrate,a single magnetic wire can capture 6.67 g of titanium concentrate with a grade of 28.28% under appropriate test conditions.In this paper,the research on the capture characteristics of the rotating magnetic wires of the centrifuged high gradient magnetic separator of the Cen Mag-100 is of great value to reveal the capture characteristics and laws of the rotating magnetic wire,to optimize and improve the structure of the equipment,and to provide theoretical basis for the development of new technology and equipment.