Hematite (chemical composition Fe2O3) is a weakly magnetic mineral whose crystal belongs to the oxide mineral of the hexagonal crystal system, and the mineral form is mainly iron oxide. According to the composition, it can be divided into variant hematites such as ilmenite, aluminum hematite, mafic hematite, and water hematite.
Hematite is widely distributed and involves many types of minerals, so the method of beneficiation is not single. The main beneficiation methods include the gravity beneficiation method, flotation method, weak magnetic method, and roasting beneficiation method.
Hematite Gravity Beneficiation Process
There are two types of hematite gravity beneficiation methods, one is coarse-grained gravity beneficiation. Some deposits have higher geological grades (about 50%), but the ore bodies are thinner or have more interlayers, and waste rocks are mixed in during mining to deplete the ore. For this kind of ore, the method of only crushing and not grinding can be used. In the case of coarse particles, the coarse-grained tailings are discarded through gravity beneficiation, thereby improving the iron ore grade.
The other is fine-grained gravity beneficiation, which is mostly used to process hematite with finer grain size and higher magnetic properties. After crushing, the ore is ground to separate the mineral monomers, and then the gravitational beneficiation is carried out to obtain fine-grained high-grade concentrate.
However, since most of the weak magnetic iron ore concentrates are not of high grade, and the unit processing capacity of the gravity beneficiation process is low, the combined process of strong magnetic separation and gravity beneficiation is often used. That is, a large number of unqualified tailings are discarded by a strong magnetic separation process first, and then a gravity beneficiation process is used to further process the strong magnetic concentrate to improve the grade of the concentrate.
Magnetic Separation of Hematite
The magnetic separation method of hematite mostly adopts the weak magnetic-strong magnetic separation method, which is mostly used to process the mixed magnetite-hematite ore. After the weak magnetic separation tailings are concentrated, the strong magnetic roughing and sweeping are carried out, and the strong magnetic rough concentrate is concentrated by the strong magnetic separator. Because a small amount of strong magnetic minerals in the magnetite in the ore easily causes the blockage of the strong magnetic separator, when the strong magnetic separation process is used, it is usually necessary to increase the weak magnetic separation operation before the strong magnetic separation operation to remove the ore. Strong magnetic minerals.
Another method is the strong magnetic flotation method, which mainly discharges gangue minerals such as quartz and chlorite in the ore through strong magnetic separation, and the magnetic separation coarse concentrate is further finely ground into the flotation production qualified concentrate.
Hematite Flotation Method
The flotation process is mainly used to extract fine and particulate weakly magnetic iron ore, including positive flotation (positive flotation with anionic collectors) and reverse flotation (reverse flotation with cation collectors). Commonly used collectors are soybean oil fatty acid sulfated soap, oxidized paraffin soap, crude Thar oil, third-line alkali residue, chlorinated acid, oxidized kerosene, petroleum, sodium sulfonate, cornflour, and so on.
Hematite Roasting Magnetic Separation Method
When the mineral composition is complex and other beneficiation methods are difficult to obtain good beneficiation indicators, the roasting magnetic separation method is often used to extract hematite. The roasting magnetic separation method is mainly to magnetically roast the ore to convert hematite or false hematite into magnetite, and then use a weak magnetic field magnetic separator for separation.
In order to further improve the grade of iron concentrate, fine screen regrinding and redressing (which can increase the grade of the concentrate to more than 65%), regrinding and reverse flotation (which can increase the grade of the concentrate to 66%) and other processes are often used in production. The iron concentrate obtained by magnetic separation is further processed.
The above are the common beneficiation methods of hematite. For the beneficiation of hematite, we suggest that it is best to develop a process that suits you through the beneficiation test, and remember not to apply it randomly.
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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