The classification of minerals by magnetism is based on specific susceptibility (X), The greater the difference in specific susceptibility of minerals, the easier the separation.
According to the specific magnetic susceptibility of minerals, all minerals can be classified into the following types
(1) Strongly magnetic mineral X>4.0×10-5 m3/kg, it can be recovered in the weak magnetic separator, its magnetic field strength up to 480 ~ 1840 kA/m
strong magnetic minerals include magnetite, maghemite, titanomagnetite, pyrrhotite and zinc-iron spinel, etc. Most are ferrimagnetic mineral.
(2) Medium magnetic minerals X=1.26×10-7~ 7.5×10-6m3/kg, it can recovered in the magnetic separator with magnetic strength H = 480 ~ 1840,kA/m.
medium magnetic minerals includes most iron – manganese minerals like hematite, specularite, siderite, goethite, manganite, psilomelane, pyrolusite, rhodochrosite, etc.; and some titanium, chromium and tungsten-containing minerals, like ilmenite, rutile, chromite, wolframite, etc.; rock-forming mineral biotite, hornbeam, chlorite, epidote, garnet, olivine, pyroxene, etc.
(3) Weak magnetic minerals X<1.26 X10-7 m3/kg, it cannot be recovered by magnetic separation.
this type mineral includes some metal minerals: molybdenite, sphalerite, galena, stibnite, scheelite, cassiterite, arsenic-nickel ore, gold, etc.; most non-metallic minerals: coal, natural Sulfur, diamond, kaolin, gypsum, fluorite, etc.; most rock-forming minerals: quartz, feldspar, calcite, etc. Some of these minerals are paramagnetic substances, and some are reverse magnetic substances such as galena, gold, stibnite and natural sulfur.
It should be pointed out that the above classification is based on the current level of magnetic separation technology, and there are certain discrepancies in the specific classification indicators of various countries, especially the boundary between weak magnetic minerals and non-magnetic minerals, which will follow the development of magnetic separation technology. The magnetic field force of the machine is gradually weakened, so this is only a rough classification. In addition, the magnetic properties of minerals are also affected by the size and shape. Therefore, for a specific mineral, it is necessary to actually measure the magnetic size of the mineral.