Effect Of Coaxial Electromagnetic Field On The Separation Of Dense Medium Cyclone

In recent years,the magnetic field has been applied to regulate the separation of the secondary product of the three products dense medium cyclone.In order to optimize the magnetic field on the three products dense medium cyclone two sorting on-line regulation and in this experiment,we have designed and manufactured a rectangular coil with 80 mm high,150 mm and 200 mm in diameter,and a 60 degree trapezoidal coil.By Ansoft finite element software,the force of the magnetic particles in the coil is simulated.The coil was placed at different positions outside the dense medium cyclone and the coarse coal slime separation test was carried out.Firstly,the basic properties of the magnetic field generated by the energizing coil are studied by Ansoft finite element software.The ratio of the radial force to the axial force of the magnetic force in the coil is calculated by the finite element software only with the shape of the coil,which is not related to the magnitude of the current passing through the coil.The ratio of the radial force and the axial force of the magnetic particles in the same position inside the coil decreases as the inner diameter of the coil decreases,and the magnitude of the resultant force of the magnetic force decreases as the inner diameter of the coil increases.The magnetic force of the magnetic particles in the rectangular coil is symmetrical about the center level of the coil,and the magnetic force in the trapezoidal coil is asymmetrical.The axial force of the downward direction path is long,but the value of the axial force is small.The axial force path is short but the value of the magnetic force is large.Therefore,the effect of the magnetic field can be analyzed according to the basic properties of the magnetic field.In this experiment,the rectangular coil with inner diameter of 150 mm is placed at different positions outside the dense medium cyclone.By changing the magnitude of the excitation current of the magnetic system,the-3mm coarse coal slime is used as the research object.The overflow products and the underflow products of the dense medium cyclone were used as the macro indicators.The experimental results show that when the magnetic field is located in the middle and lower position of the cone of the dense medium cyclone,the separation density of the dense medium cyclone can be effectively reduced when the excitation current is large.At this time,the ash content of the clean coal is reduced with the ash content of the tailing coal at the same time,and when the top plane of the magnetic system is located at 160 mm below the column cone interface of the heavy medium cyclone,the excitation current of the dense medium cyclone begins to decrease.When the excitation current is 10 A,the separation density of the dense medium cyclone begins to decrease.In this paper,the effects of different shapes of magnetic systems on the ash of overflow products and the underflow product at 200 mm at the interface of the heavy cone of the dense medium cyclone were studied.The experimental results show that in the range of large excitation current(12.5A-17.5A),the dense medium cyclone is less effective in the 200 mm rectangular coil with larger diameter than the trapezoidal coil with 60 °.The effect of a rectangular coil with inner diameter of 150 mm is similar to the effect of the test in the fourth chapter.Combined with the third chapter,it can be concluded that the reduction of the density of the dense medium cyclone requires a larger direction of the magnetic field force.The rectangular coil with an inner diameter of 150 mm was used to continue upward.It can be found that as the coil moves upwards.The ash content of the overflow product and underflow product when the top of the coil is over the the column cone interface of the dense medium cyclone at 40 mm is higher than those when the top of the coil is below the the column cone interface of the dense medium cyclone at 40 mm.It is indicated that under the action of small current with the coil position in the dense medium cyclone column cone at the interface near the location of the rise,the same current under the dense medium cyclone sorting density increased more obvious.Therefore,to increase the separation density of the heavy medium cyclone,it is necessary to move the position of the coil upwards to the cylinder section of the dense medium cyclone.In this paper,through the experimental system of the laboratory and the coil with different shapes and inner diameter,the range of current range of promoting and reducing the dense medium cyclone is basically determined.The comparison of the density of the magnetic system in different positions and the reduction of the density of the dense medium cyclone is made,which lays the foundation for the industrial application of the on-line regulation of the threestage dense medium cyclone in the coal preparation industry.