What is the basis for mineral classification by magnetics?

(1) Strong magnetic minerals Its material specific magnetic susceptibility; c is greater than 3000 × 10-6 meters. /g. Magnetic field strength H may be selected in a 7200 ~ 136 000 A / m of weak magnetic separator, the material is easy to beneficiation. Few of these minerals, the main magnetic iron ore, maghemite (gamma] hematite), titanium magnetite, pyrrhotite, zinc ferrite, etc., most of these minerals belonging ferrimagnetic substance.

(2) Medium magnetic mineral The material magnetic ratio x is between (600 ~ 3000) × 10-6 cm 3 / gram. Only ilmenite and imaginary hematite belong to this type of mineral. The selection of such minerals requires the use of a magnetic separator with a magnetic field strength H of 160,000 to 480,000 amps/meter.

(3) weak magnetic minerals whose material ratio is magnetic susceptibility) (between (15 ~ 600) × 10-6 cm 3 / gram, can be selected in a strong magnetic separator with magnetic field strength H = 480000 ~ 160,000 amps / m) . the most out of these minerals, including easy to choose, but also difficult to choose are: most of the iron-manganese mineral - hematite, hematite, limonite, siderite, water manganese ore, manganese ore, Hard manganese ore, rhodochrosite, etc.; some minerals containing chromium , tungsten, chromite, black serpentine, olivine, garnet, pyroxene, etc.

Most of these minerals are paramagnetic and also antiferromagnetic.

(4) Non-magnetic minerals The material magnetic ratio is less than 15<10-6 cm3/g. Such minerals are many, the main part of the metal minerals - Hui copper ore, galena, sphalerite, stibnite, scheelite, cassiterite, gold, etc., most of the non-metallic minerals - sulfur, coal , graphite , diamond , gypsum , kaolin, etc., most of the rock-forming minerals - quartz , feldspar , calcite and so on. Some of these minerals are paramagnetic and some are antimagnetic. The so-called non-magnetic minerals are not absolutely non-magnetic, but only very small. The magnetic field strength that can be achieved in current magnetic separators cannot be selected, so it is called non-magnetic minerals.

The above classification is roughly classified under the conditions of modern technology, because there are many factors affecting the magnetic properties of minerals, even if the magnetic properties of different mineral origins are not identical. It should be noted that as magnetic separation technology develops, the boundaries between weak magnetic minerals and non-magnetic minerals will change. The lower limit of the magnetic permeability of weak magnetic minerals is decreasing, which is an inevitable trend in the development of magnetic separation.