| Iron ore is the basic raw material in iron and steel industry. High grade ofiron ore concentrate is required by the steel industry, and the measures toimprove the grade of iron concentrate mainly depend on three ways: new typeof high-efficiency magnetic separation equipment, reverse flotation and thecombination of magnetic separation and reverse flotation. In the reverseflotation process of magnetite, the existence of coarse slime can affect theseparation process. In order to create favorable conditions for the beneficiationprocess and get the qualified concentrates, it is necessary to remove slimebefore the preparation process. Therefore, with the purpose of increasing ironcontent and reducing silicon content, the desliming and concentratingexperiments are designed and processed with the magnetic cyclone.A Φ100mm magnetic cyclone was designed and processed, and theseparation experimental system was constructed to study the effect ofparameters (cyclone cone angle, magnet position and magnetic field intensity、the combination of magnet, feeding pressure and pulp density) which influencethe separation effect of magnetic cyclone. It showed that: in the presence of a magnetic field, the underflow productwith yield of82.20%, Fe recovery of61.49%, SiO2content of10.75%isachieved under the effect of a single coil and cone of90°. The underflow ironrecovery of98.96%and grade increased from57.95%to60.36%can be gotafter using the dual coil to increase the intensity and space of the magnetic field.The use of dual coil can reduce the metal loss of overflow and remove part ofthe fine slime, which can improve the quality of the underflow. The use ofdual-coil can also enable pulp density concentrated from15%to48.83%, reducethe material amount of subsequent processing operations. The desliming effectof magnetic cyclone is obvious to fine slime but not to the coarse particles, sothe prior removal of coarse underflow product is conducive to improve thegrade of iron concentrate of underflow product.The effect is better under the condition of multi-coil and cone of90°inthat the overflow product yield reach to90.91%, which means little metal loss.Whereas the product yield increase as electric current increases when usingsingle-coil.When the pressure is0.08MPa, as the electric current increases,underflow yield rose from67.49%to90.37%,overflow yield fell to8.35%from28.86%, side overflow yield fell from3.65%to1.28%. Lower pressure helps toreduce the metal loss in that with the increasing concentration of the material,underflow yield decreases. High concentration increases the loss of metal, so thebetter mass concentration is15%.Applying a magnetic field in the overflow room, the using of permanent magnetic field failed to achieve the purpose of increase recovery of metals;electromagnetic field can increase the underflow and overflow side yields tovary degrees, reduce overflow yield, reduce metal loss; applying a magneticfield in the central cone and overflow flow chamber can enhance the metalrecovery of underflow, but it is proved to be ineffective to the recovery of sideoverflow.The finite element analysis software ANSYS was used to simulate andanalyze the magnetic system. The simulation results showed that: the change ofmagnetic induction intensity of coil central axis simulated by ANSYS coincideswith the actual measured value rule, which can reflect the real propertiesmagnetic field. Magnetic force existence in both axial and radial direction afterthe coil is energized, the magnetic field gradient and magnetic force are bothlarge close to the vertical plane of coils which can attract the magnetic particlesto the region; the closer to the inner wall of the magnetic field, the greater themagnetic field gradient. The force that magnetic particles in the radial directionget from the magnetic field direct to external, which can strengthen theiroutward movement swirl.The magnetic cyclone has a certain desliming effect and can improve themagnetite concentrate grade, which prove to be good magnetic enrichmentequipment. |
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