Research On The Magnetic System Optimization Of The Permanent Magnetic Field Control Of Dense Medium Cyclone Separation Density

As an efficient separation equipment, three products dense-mediumcyclone has been widely used in coal preparation industry. However the secondsection density of the cyclone is difficult to online control which has alwaysbeen a core problem to be solved in coal preparation industry. The NdFeBPermanent magnets were used in the paper to build radial permanent field whichwere acted on the dense medium cyclone to adjust the separation density inorder to get the optimal magnetic system.The medium distribution rule was studied by arranging double magneticsystem which is formed by alternating polarity four poles (N-S-N-S) and threetimes magnetic system which is formed by alternating polarity six poles(N-S-N-S-N-S). Research shows that double and three times magnetic systemcan affect the medium distribution of the cyclone, with the increase of magneticthickness, the density variation of the overflow and underflow is more obvious.The coarse slime separation experiment is conducted by acting doublemagnetic system on the vortex finder and cylinder bottom and the cone top and among the cone and cone bottom and spigot, and the influence law of separationdensity is studied. Studies show that, the separation density decreases when themagnetic system is acted on the vortex finder; the separation density increaseswhen the magnetic system is acted on the spigot; the normal cyclone separationcan be destroyed by the permanent magnetic field when the magnetic system isacted on the cylinder bottom and the cone top; and the two-way regulation ofseparation density can be achieved with the change of the thickness of themagnetic system when the magnetic system is acted on the cone bottom.The coarse slime separation experiment is conducted by acting three timesmagnetic system on the vortex finder and cone bottom, and the influence law ofseparation density is studied. Studies show that, the separation density decreaseswhen the magnetic system is acted on the vortex finder, and the effect is betterthan double magnetic system; and the two-way regulation of separation densitycan also be achieved with the change of the thickness of the magnetic systemwhen the magnetic system is acted on the cone bottom.I and II tooth plate are designed and NdFeB permanent magnets areeffective combined to build two alternate arrangement of high gradient magneticdepartment. And they are acted on the vortex finder and cone bottom and spigot,and the medium distribution rule was studied. Research shows that the two highgradient magnetic department can also affect the medium distribution of thecyclone, with the increase of magnetic thickness, the density variation of theoverflow and underflow is more obvious. The coarse slime separation experiment is conducted by acting I and IItooth plate on the vortex finder and cone bottom and spigot, and the influencelaw of separation density is studied. Research shows that the effect is better thanthe double magnetic system, and I tooth plate is superior to the II.The magnetic field characteristics of double and three times magneticsystem are analyzed by using the electromagnetic field analysis function ofANSYS software. The simulation results show that the greater the thickness ofthe magnetic system, the greater the magnetic force acted on the magneticparticles, and the magnetic line distribution of three times magnetic system ismore uniform than double magnetic system, which is helpful of the adsorptionof the magnetic particles. Simulation results reveal the reason of dense mediumcyclone separation density can be adjusted by the permanent magnetic field isthat the migration and enrichment of the magnetic particles to the cyclone wallcan be strengthened by the permanent magnetic field.