The Theoretical Basis Of Magnetic Separation
Jun 14, 2018

Separation process of magnetic separation

     When the slurry enters the separation space, the magnetic particles are magnetized under the action of the uneven magnetic field, which is attracted by the magnetic field and sucked on the cylinder, and then transferred to the end of the ore drain and discharged into a magnetic product. Nonmagnetic mineral particles are still retained in ore pulp due to their very small magnetic field force and are discharged into non-magnetic products. This is the separation process of magnetic separation.

Basic conditions for magnetic separation

     Mineral particles are affected by magnetic force and mechanical force (gravity, centrifugal force, medium resistance, friction force, etc.) through the magnetic field of the sorter. The magnetic particles with stronger magnetic properties are stronger than the mechanical force they receive, while the magnetic particles of non magnetic minerals are very small, and they are dominated by mechanical force. As the resultant force of magnetic force and mechanical force on various ore grains is different, their trajectories are also different, so as to realize sorting.

     Classification of mineral magnetism according to magnetism is the basis for mineral magnetic separation. Because of the different atomic structure of various substances in nature, they have different magnetic properties. 

     In the practice of production, from a practical point of view, the minerals can be divided into four categories according to the difference in the magnetic moment (that is, the coefficient of magnetization) when the body mass is magnetized in an external magnetic field of the intensity of a unit magnetic field.

a. Strong magnetic minerals such as magnetite, pyrrhotite, magnetite and zinc ferrospinel. Such minerals can be effectively sorted by weak magnetic equipment.

b. Magnetic minerals, such as semi-illusion hematite and certain hematite, chromite and so on. Medium magnetic field magnetic separation equipment for this type of mineral can be sorted.

c. Weak magnetic minerals, such as hematite, limonite, mirror iron ore, siderite, manganite, pyromanganese, hard manganese, manganite, hematite, wolframite, wolframite, Garnet, chlorite, etc., are to be recovered by strong magnetic separation or other methods.

d. Non-magnetic minerals, Such as calcite, feldspar, cocoon, Galena, quartz, barite, lead, pyrocopper, sphalerite, antimony, natural gold, cassiterite, alfalfa, coal, graphite, diamond, gypsum, Kaolin.

The magnetic characteristics of strong magnetic minerals are:

a. Magnetization and magnetic system are very large and there is magnetic saturation. Under the lower external magnetic field, the minister can achieve

b. There is a curve relationship between the magnetization, the coefficient of magnetization and the strength of the external magnetic field, and the coefficient of magnetization is not a constant. In addition to mineral properties, magnetization is also related to the history of changes in external magnetic fields.

c. Magnetite has a hysteresis phenomenon, and when it leaves the magnetization field, it still retains a certain amount of residual magnetism; To remove the residual magnetic field, you need to add a reverse magnetic field. The anti-magnetic field strength that completely removes the residual magnetic field is called stubborn magnetic force.

d. Its magnetic change is related to temperature. When the temperature is higher than the critical value-Curie point, the internal magnetic domain structure disappears and appears paramagnetic.(Under the action of the external magnetic field, its atomic magnetic moment has a tendency to turn to the direction of the external magnetic field. The stronger the external magnetic field, The greater the probability of outward magnetic orientation. The more magnetic O, the material is called paramagnetic material. )

e. In addition to being related to the strength of the external magnetized magnetic field, the magnetic variation is also affected by its own shape, particle size and degree of oxidation.


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