Introduction of the mineral magnetism and magnetic characteristics of strong magnetic minerals

3/5/2012 8:26:18 PM

Mineral magnetic is the basis of mineral magnetic separation, Because of the nature of the atomic structure of the different material, it has different magnetic atoms. The magnetic material is from the magnetic atoms. In Physics, substance is divided into three categories: reverse magnetism, the magnetic, ferromagnetism (ferrous magnetic, the ferromagnetic)

In magnetic separation practice, the mineral is divided into strong magnetic minerals, weak magnetic minerals and the nonmagnetic minerals according to the size of specific susceptibility. 

①     Weak magnetic minerals: This kind of mineral belongs to the ferrous magnetic material, such as magnetite, magnetic pyrite, magnetic hematite and zinc, iron spinel, etc. This kind of mineral can be recycled by magnetic separation machine with weak magnetic field intensity. 

②    strong magnetic minerals: they can be recycled by strong magnetic separation machine with magnetic field intensity H = 1 ~ 2 T. there are many mineral of this kind, such as iron mn, hematite, mirror, limonite and iron ore, manganese ore, using, soft hard titanium iron ore, chromite, black tungsten mine, etc. Part of the rock minerals such as black made mica, Angle flash stone, chlorite, hauling, olivine, garnet, electrical stone, pyroxene, etc. This kind of mineral mostly belongs to the magnetic material, also have the ferromagnetic materials.

③    nonmagnetic minerals: In the current technology conditions, it still can't be recycled by the magnetic separation method. many of the minerals belong to this kind of the minerals, such as part of the metal mineral-copper, lead, zinc sulfide ore and oxide minerals, white tungsten, tin stone, gold, etc.; Most of the non-metallic minerals-natural sulfur, graphite, diamond, plaster, fluorite, kaolin, coal, etc.; Most of the rock mineral made-adaptation, feldspar, calcite, etc. some of this kind of mineral belong to the magnetic material, also some belong to the inverse magnetic material.

Something ought to be pointed out is that the magnetic minerals are influenced by many factors. Mineral Magnetism from different habitats and different mines is different, sometimes even have very big difference, this is because they are in different ore-forming conditions and with different content of impurities and different crystal structure. To a specific mineral from certain habitats, its magnetic size can be gained through the mineral magnetic determination.

magnetic characteristics of weak magnetic minerals: Magnetite can be used as a classic representative of strong magnetic minerals, it belongs to ferrous magnetic material; it have more complex magnetism due to its internal magnetic structure (namely Spontaneous magnetization over small area), the magnetic characteristics can be summed up in the following:

①    Magnetic strength and magnetized coefficient is very big, with the phenomenon of magnetic saturation, and can be saturated in the lower external magnetic field intensity.

②    There are curvilinear relationship between Magnetic strength, magnetized coefficient and the external magnetic field intensity, and magnetized coefficient is not a constant. Strength of minerals is in relevant with its properties, but also to the historical change of external magnetic field.

③    There are hysteresis of minerals, it still retain some residual magnetism when it deviate from magnetized materials; To remove residual magnetism, a reverse magnetic field should be added to completely remove the magnetic field intensity H, which is called coercive force

④    The magnetism change with temperature, there will exist the phenomenon of paramagnetism when the temperature is higher than the critical temperature-Curie and its internal magnetic structure is small.

⑤    The magnetism changes with the strength of magnetic field in the outside, but also with shape and size of its own particle and degree of oxidation.