The Permanent Magnetic Field Online-Control Research On The Separation Density Of Dense Medium Cyclone

In order to find a method of online controlling the separation density of heavy medium cyclone, taking rectangular permanent magnets to produce permanent magnetic field, a feasibility study on the online magnetic control of the vortex finder diameter of dense medium cyclone was carried out. The effect of permanent magnetic field on the medium distribution was researched by applying magnets on the vortex finder, spigot and cones, and some test conditions were selected to do the coarse slime separation experiment. The magnetic field characteristics was analyzed and magnetic pole was optimized by using the finite element analysis software ANSYS.Tests were conducted by arranging permanent magnets on the non-magnetic tube, recording’the flow and pressure of pipeline under different magnet thicknesses and comparing with those of DN50X40reducing pipe under the same conditions. The results show that, the flow and pressure of non-magnetic tube are more close to those of reducing pipe with the increase of magnet thickness, and suggesting that magnetic field can realize the pipe diameter reducing. When the motor frequency is lower, the flow section of the pipe is reduced from50mm to40mm.The effect of different arrangements and thicknesses of magnetic pole on the medium distribution were researched by applying magnets on the vertex finder, spigot and cones. The results show that, when magnets are arranged on the vortex finder and cones, the overflow medium yield decreases with the increase of magnet thickness, and suggesting that the separation density decreases; when magnets are arranged on the spigot, the overflow medium yield increases with the increase of magnet thickness, and suggesting that the separation density increases.According to the medium distribution laws, some test conditions were selected to do the coarse slime separation experiment. When magnets are arranged on the vortex finder, the overflow ash content decreases with the increase of magnet thickness. When magnets are arranged on the spigot, the underflow ash content shows a tendency of decrease at first and then increase with the increase of magnet thickness. When magnets are arranged on the cones, the overflow and underflow ash content increase at first and then decrease with the increase of magnet thickness. The results of coarse slime separation experiment show that, the separation density of dense medium cyclone can be adjusted by applying magnetic field.The magnetic field distribution of four-pole, different magnet thicknesses and four-pole, six-pole,5mm magnet thickness were analyzed by using the magnetic field analysis function of the finite element analysis software ANSYS. The simulation results show that, when four-pole, the larger the magnet thickness, the stronger the magnetic field intensity and the magnetic induction intensity, when the magnet thickness is larger, magnetic force distribution is even in circumferential direction and which benefits the adsorption of magnetic particles; when six-pole, the magnetic induction lines are more intensive, the magnetic field intensity and the magnetic induction intensity are more stronger. Six-pole arrangement is superior to the four-pole arrangement.