Design And Experimental Study On Magnetic Leakage Column Magnetic System

Iron is the most important metal material in the construction of the national economy and the first consumpted metal in the world.Although iron ore resources of China are rich, there are few high-grade ore resources and many low-grade ore resources and fine particle size distribution. With the continuous exploitation of resources, iron ore which are characterized by low grade, fine grain, complicated is gradually significant, so the selection of other iron minerals are required more complex. Under the environment of market recession of iron ore resources, developing the new mineral processing equipment to solve fine and low grade iron ore can improve quality of the concentrate, then, not only can save resources, but also enable enterprises to reduce production costs.Magnetic flotation column based on CFC/CPT flotation column of Changsha Research Institute of mining and metallurgy is the research and development of a new type of mineral processing equipment which adds excitatied system outside the flotation column.Use its electric energy to generate the background-magnetic-field which separates the objective minerals and non-target mineral for achieving sorting purposes. Therefore, magnetic flotation column research focus on the excitation system which determines good or bad sorting effect.In this article, the magnetic system structure is designed by the finite element software ANSYS.The simulation results are as follows:Simulating analysis of a single set of different section-shape magnetic system found that magnetic system and magnetic properties are closely related. Under the same exciting current, producing section of the maximum magnetic field strength is a square in different kinds of shape; In the different current,the coil system producing magnetic field intensity and variation of magnetic field gradient is same to variation of current; Increased range of magnetic force is two times as much as the multiples of exciting current increasing; The change law of the magnetic field characteristic of the two groups of the same number of turns is the superposition of the magnetic field characteristics of the two groups of single coil;With the increase of the distance between the two groups of coils, the magnetic field intensity,the magnetic field gradient and the magnetic force change the superposition from two independent groups of coil magnetic field characteristics of the magnetic system.Through the change of the three groups of turns, the number of turns ratio is not more than 0.5 times in order to make the magnetic field strength, the magnetic field gradient and the magnetic force obviously increases gradually along the axial direction; Most magnetic lines are closed in the air using the non-magnetic material as the cylinder wall, and the magnetic flux density in the air gap is higher than that of lateral separation; And there are almost tno magnetic field distribution in the separation chamber using the magnetic material as the cylinder wall. Magnetic flux density inside wall was higher than that of magnetic material outside wall, As for the magnetic permeability of magnetic material is higher than that of air and the magnetic field of magnetic material go straightly through the sorting gap. Therefore magnetic field lines are constrained in the separation space. The jet catheter is also established.The comprehensive stress analysis is carried out on the mineral particles in the magnetic field zone of the magnetic column flotation as well as the complex force field, including analysis of different sizes and different magnetite intergrowths. Through theoretical prediction the magnetic system can effectively separate 0.025mm-0.075 magnetic particles. And then DLVO theory was used to analyze “the magnetic aggregation-dispersion” of magnetite and quartz under different pH conditions. when pH=7, magnetite and quartz is in a slight state of agglomeration, and between magnetite exist strong magnetic force; when pH=11, magnetite and quartz in dispersion state, and between magnetite still exist strong magnetic force.The results of artificial mixed mineral experiments are as follows:(1) Tests of CPT-magnetic column flotation under the different exciting current show as follows: Grade of tailings as 9.36% from flotation without magnetic field reduced to magnetic flotation with 2.85%, and Recovery rate is increased by nearly 10%; There are 84.71% under the 38 μm for concentrate of flotation without external magnetic field.Then There are 89.05% under the 38μm for concentrate of flotation with external 1.9A current.(2) Tests of CFC-magnetic column flotation show as follows: Along the excitation intensity increasing can still reduce the tailings grade with the amount of. As starch decreased, concentrate grade with 46.66% increased to 51.06%, and recovery rate is improved.Under the amount of starch 1000 g/t condition, excitation intensity from 0A to 1.9A, still can make the tailing grade from 2.40% reduced to 1.07%. The introduction of magnetic field force can play a role in the inhibition of the "magnetic priming effect"; Under the exciting current of the 1.9A,along the amount of starch from1000g/t reduced to 0g/t tailing grade firstly decrese from 1.07% to 0.78%,then increased by 3.02%, but concentrate grade from 46.66% increased to 51.06%, recycling lead from 98.93% increase to 99.24% reduced to 96.98%. Therefore, under the condition of applying the excitation current, reducing the dosage of a certain amount of inhibitor is beneficial to increase the concentrate quality and improve the recovery rate.