Overview
Considering the physical and chemical properties of hematite, such as magnetism, floatability, and density, the beneficiation methods of hematite include: magnetic separation, flotation beneficiation, gravity beneficiation, etc. These methods can constitute a variety of different beneficiation processes. For different types of hematite, the degree of difficulty of beneficiation is also different. Today, we share how to judge the difficulty of hematite beneficiation.
Difficulty Level of Gravity Beneficiation of Hematite
The density of hematite is relatively high, and gravity beneficiation is an important separation method for hematite. The table lists the characteristics of iron minerals and gangue minerals with different densities.
| Iron Ore Density (g/cm³) | Gangue Density (g/cm³) | Washability Coefficient E | Difficulty Of Gravity Beneficiation |
|---|---|---|---|
| 5.0 | 3.2 | 1.82 | Easy |
| 5.0 | 3.0 | 2.00 | Easy |
| 4.5 | 3.2 | 1.60 | Moderately Easy |
| 4.5 | 3.0 | 1.75 | Easy |
| 4.0 | 3.2 | 1.36 | Difficult |
| 4.0 | 3.0 | 1.60 | Moderately Easy |
The density of hematite is generally above 5.0g/cm³, and it is easier to separate common gangue minerals by gravity beneficiation. It should be pointed out that the difficulty of gravity separation is also related to particle size. For coarse-grained disseminated ore with a monomer separation particle size greater than 0.5mm, it is easier to separate with gravity beneficiation. For medium and fine-grained disseminated ore with a monomer separation particle size of 0.15~0.04mm, the processing capacity and separation of gravity beneficiation equipment The separation efficiency is significantly reduced. For fine-grained iron minerals smaller than 0.03mm, the current gravity separation equipment is difficult to effectively recover.
Difficulty Level of Magnetic Separation of Hematite
Hematite is a weakly magnetic mineral, while pseudo-hematite is more magnetic. The order of magnetic strength of common weakly magnetic minerals is:
Phantom hematite (or Semi-phantom hematite)> Specularite> Hematite> Siderite> Limonite
Normally, phantom hematite or semi-phantom hematite can be recovered by a magnetic separator with a medium magnetic field of about 6000-8000 Oe, while a strong magnetic separator with a magnetic field of about 12000 Oe is required to recover hematite. Specularite is somewhere in between, and the separation magnetic field strength is generally 8000~10000 Oe. For limonite and siderite, the separation magnetic field strength needs more than 15000 Oe. If there are weakly magnetic silicate minerals such as biotite and garnet in the gangue, it is difficult to separate them from iron minerals in a strong magnetic field above 12000 Oe.
Difficulty Level of Flotation Separation of Hematite
The floatability sequence of weakly magnetic minerals such as hematite is:
Hematite> Specularite> Siderite> Limonite
When the ore contains non-ferrous metal sulfide ore, the flotation method is generally used to separate the sulfide from the iron mineral. When the ore contains calcite, dolomite, magnesite, fluorite, apatite, and other easily floating calcium and magnesium minerals, the flotation method is often used to separate them from iron minerals. But this time is more difficult than before, because flotation minerals generally use fatty acid type collectors for these minerals, which are less selective, and they can also collect iron minerals.
In addition, a large number of metal ions in the slurry activate the iron minerals and the existence of sludge, which makes the selectivity worse. For single iron ore using positive flotation beneficiation or reverse flotation beneficiation, although the particle size of the recovered iron minerals can be very fine, the impact of sludge is very serious. Therefore, it is not easy to obtain high beneficiation indexes by adopting single flotation beneficiation.
Gongyi Forui Machinery Factory is a high-quality enterprise specializing in the production of beneficiation equipment. Over the years, it has produced gravity beneficiation, magnetic separation, flotation, and other beneficiation equipment, and has accumulated a lot of practical experience. Forui Machinery is involved in lead-zinc ore, gold ore, fluorite, barite, pyrite, hematite, limonite, magnetite, manganese ore, antimony ore, tungsten ore, tin ore, celestite, etc. In the field of beneficiation of a variety of minerals, fruitful results have been achieved.
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