Experimental Study On The Separation Performance Of Magnetic Cyclone

Treatment of sewage by the magnetic seeding enhanced coagulation process has the advantages of rapid settling speed and high separation efficiency.At present,high gradient magnetic separators are commonly used to recover magnetic seeds,which have the problems of large investment,high energy consumption,low operational flexibility,and low recovery rate.In this paper,magnetic cyclone was used to recover the magnetic seeds in the flocs.By analyzing the movement of flocs in the swirling flow field,combined with numerical simulation and laboratory tests,the separation mechanism of the magnetic cyclone was demonstrated.And magnetic seeds low cost recycling were realized.Research has important theoretical and practical significance.Firstly,through the analysis of the force of flocs under compound force field,the relationship between strong shear force and flocculation breakage in the flow field was discussed.Based on the study of velocity and pressure distribution.Derive the formula for calculating the final velocity of subsidence of the magnetic seed in the magnetic cyclone.According to the formula,the increase in the final velocity of sedimentation accelerates and the discharge from the underflow port of the magnetic seed under the magnetic force,which is beneficial to increase the magnetic seed recovery rate.Second,using the fluid dynamics software and multi-physics coupling analysis software to study the internal flow field and magnetic species recovery rate,the results show that the strong shear force of the magnetic cyclone can cause the magnetic floc to break quickly.The location of the strong shearing force is near the wall surface,and the energy dissipation rate of the concrete varies greatly.Part of the lost energy is used for the crushing of magnetic floc bodies;the speed of particle sedimentation increases under the effect of magnetic force.It is favorable for the magnetic seed to be discharged from the underflow port,which can increase the recovery of magnetic seeds.In order to verify the simulation results,a test stand was finally built and a separation performance test was conducted.The influence of the feed pressure,the diameter of the underflow port,the position of the magnetic field,and the strength of the magnetic field on the separation effect of the magnetic cyclone was studied.The optimal parameter combination was optimized by the orthogonal test.The results show that the magnetic seed recovery rate is 37%higher than that of the ordinary cyclone.Appropriately increasing the current intensity can increase the recovery rate of the magnetic species.However,the magnetic species is adsorbed on the wall by excessive assembly;Increasing the diameter of the underflow port reduces the downward running resistance and increases the magnetic seed recovery;Appropriately increasing the feed pressure can also increase the recovery rate of magnetic species,but a certain pressure is exceeded,the recovery rate of magnetic species decreases;The experiment also obtained the best placement of the magnetic field.The magnetic species recovery rate was used as the evaluation index,and the optimal parameter combination was determined based on the analysis of the orthogonal test range:Feeding pressure 0.18MPa,underflow port diameter ?8mm,current size 2A,magnetic field position from the underflow port 100mm,the magnetic species recovery rate can reach 98.1%under the operating conditionsThe research results can be applied to the recovery of magnetic seeds in the magnetic coagulation wastewater treatment process,which has a broad market prospect.