The iron ore processing and production process refers to the production process in which the mined iron ore must be processed and produced by various operations to obtain concentrates that meet the smelting requirements. Mainly include: ore crusher crushing and vibrating screen screening, ball mill grinding and classifier classification; mineral separation, such as gravity separation, flotation and electric separation, etc.; mineral dehydration, including concentration, filtration, drying and other production processes . Iron ore processing and production equipment includes feeder, crusher, ball mill, classifier, vibrating screen, shaking table, magnetic separator, mixing drum, flotation machine and other equipment.

iron ore beneficiation method

We have introduced four common types of iron ore above. Today, this article will introduce the production process of these four common types of iron ore.

The beneficiation method of iron ore can be divided into several processes according to the type and nature of iron ore. Among them, there are magnetic iron ore beneficiation, weak magnetic iron ore beneficiation and symbiotic iron ore beneficiation. Before understanding the iron ore beneficiation process, let's first understand the general division of mineral magnetism:

1.The general division of mineral magnetism

① Strong magnetic minerals

Weak magnetic separators with specific susceptibility greater than 3000×10-9m3/kg and magnetic field strength H=100-2000GS can be selected. There are mainly: magnetite, maghemite (r-hematite), titanomagnetite, pyrrhotite, zinc-iron spinel, most of these minerals belong to ferrimagnetic substances.

strong-magnetic-mineral 

② Medium magnetic minerals

The specific magnetic susceptibility is between 600 and 3000×10-9m3/kg. Such minerals include ilmenite and pseudohematite. To select such minerals, a magnetic separator with a magnetic field strength of 2000-6000GS is required.

medium-magnetic-minerals

③ Weak magnetic minerals

The specific magnetic susceptibility is between 15~600×10-9m3/kg, and the strong magnetic separator with the magnetic field strength of 6000~20000GS can be selected.

weak-magnetic-minerals

2.Magnetite beneficiation process

Magnetite mainly includes single magnetite ore, vanadium-titanium magnetite ore, magnetite-bearing mixed ore and magnetite-bearing polymetallic ore , the separation process based on weak magnetic separation process is generally used in magnetite beneficiation:

Magnetite beneficiation process

Single weak magnetic separation process

The separation operation adopts a single weak magnetic separation process, which is suitable for easy separation of single magnetite ore with simple mineral composition; it can be further divided into two categories: continuous grinding-weak magnetic separation process, stage grinding-stage separation process. 

1) Continuous grinding-weak magnetic separation process: suitable for ores with coarse inlaid particle size or high iron content. According to the embedded particle size of iron minerals, one-stage grinding or two-stage continuous grinding can be used, and weak magnetic separation is carried out after the grinding products meet the separation requirements. 

2) Stage grinding-stage sorting process: suitable for low-grade ores with finely embedded particle size. After the first-stage grinding, magnetic separation and roughing are carried out, and part of the qualified tailings are discarded, and the magnetic separation coarse concentrate is fed into the second-stage grinding (regrinding) for regrinding and selection. If a large amount of tailings can be discarded after sorting under rough grinding conditions, it is beneficial to reduce the workload of subsequent grinding and sorting operations and reduce costs.

weak magnetic separation and gravity separation

Weak magnetic separation - reverse flotation process

It is mainly aimed at the problem that the grade of some iron ore concentrates is difficult to improve, and the composition of impurities such as high SiO2 in iron ore concentrates is relatively high. The process methods include magnetic separation-cation reverse flotation process and magnetic separation-anion reverse flotation process. kind.

Weak magnetic - strong magnetic - flotation combined process

Mainly used for processing polymetallic co-produced iron ore and mixed iron ore, divided into three categories:

1) Weak magnetic separation-flotation process: It is mainly used to treat magnetite ore associated with sulfide. According to the nature of the ore.

It is further divided into two types: magnetic first and then floating and first floating and then magnetic. 

2) Weak magnetic-strong magnetic process: mainly used for processing mixed ores with low magnetic rate. The characteristic is that weak magnetic separation is used to first separate weak magnetic magnetite, and weak magnetic separation is used to separate tailings and then strong magnetic separation is used to recover weak magnetic minerals such as hematite. 

3) Weak magnetic - strong magnetic - flotation process: it is mainly used for the treatment of polymetallic symbiotic iron ore.

flotation machine

3. Hematite beneficiation method

Hematite is a kind of iron trioxide (Fe2O3) without crystal water. Limonite ore contains 35% to 40% iron, the hardness is between 5.5 and 6.5, and the specific gravity is between 4.8 and 5.3. This kind of iron ore is weak magnetic iron ore. At present, there are three common hematite beneficiation methods: gravity separation, magnetic separation and flotation.

Hematite gravity separation method

Hematite gravity separation method can be divided into single gravity separation method and spiral chute-shaker combined gravity separation method according to its mineral properties.

Single gravity separation method: according to the mineral particle size conditions, it is divided into fine grain gravity separation and coarse grain gravity separation. Among them, fine grain gravity separation is to grind the broken iron ore to dissociate its monomers, and then pass through gravity separation. To obtain fine-grained high-grade hematite concentrate, this method is suitable for hematite with fine embedded particle size and high magnetic content; the coarse-grained gravity separation method mostly adopts the method of only breaking without grinding because of its coarse mineral particle size. Gravity separation discards the crushed coarse tailings, which are mostly suitable for coarse-grained embedded hematite ore.

Spiral chute-shaker combined gravity separation method: mainly suitable for processing medium and fine-grained hematite. The spiral chute can be used for roughing first, and then the rough and concentrated iron ore can be selected by the shaking table.

Hematite beneficiation method

Hematite Magnetic Separation Method

The hematite magnetic separation method is mainly suitable for the treatment of hematite ore containing non-metallic minerals. When the slurry enters the separation stage, the magnetic ore particles can be magnetized under the action of a non-uniform magnetic field. The attraction of magnetic field makes it adsorbed on the cylinder and brought to the mine end for discharge; the non-magnetic ore gravel still exists in the pulp due to the small effect of the magnetic field.

Hematite flotation method

Hematite flotation methods are mainly two types: positive flotation and reverse flotation.

Hematite positive flotation method: mainly suitable for processing single hematite, mainly using anionic collectors to float hematite from raw ore.

Hematite reverse flotation method: It is mostly suitable for hematite with high grade and gangue is easy to float. It mainly uses anionic and cationic collectors to float hematite from the original ore.

Magnetite machine

4. Limonite beneficiation method

Limonite is iron trioxide (mFe2O3•nH2O) containing crystal water. The iron content of limonite is 35% to 40%. Its ore is soft and has a small specific gravity. At present, the commonly used limonite beneficiation methods mainly include single beneficiation process and combined beneficiation method.

 

Limonite beneficiation method

Single separation method of limonite

Limonite single gravity separation method: This process is suitable for small beneficiation plants, mainly using spiral chute for pre-enrichment, and then for selection by shaking table.

Limonite single flotation method: mainly suitable for the separation of limonite with simple properties. The process includes positive flotation and reverse flotation. In general, positive flotation is not used alone, but needs to be used in combination with strong magnetic separation. Reverse flotation can be used for single flotation by using anion and cation combination.

Limonite single strong magnetic separation method: mainly use high gradient magnetic separator to separate limonite.

Combined separation method of limonite

Limonite gravity separation - strong magnetic separation method: mainly suitable for fine-grained limonite separation. The limonite is finely crushed or rod-milled for washing, sieving and grading and desliming treatment. The concentrate is obtained, the intermediate grade is obtained by magnetic separation, and the fine grade and slime are obtained by a high-gradient magnetic separator.

Limonite selective flocculation flotation method: After fine grinding, sodium carbonate and water glass are added to the minerals to make the slurry well dispersed, and the limonite is selectively flocculated by the selective flocculation method, and then the flotation method is used. Obtain high-grade limonite concentrate.

classifier machine

5. Siderite beneficiation method

Siderite is an iron carbonate mineral (FeCO3), its iron content is below 48%, its hardness is between 3.5 and 4, and its specific gravity is 3.8. At present, the commonly used siderite beneficiation methods mainly include gravity separation method, strong magnetic separation method, flotation method and magnetization roasting method.

Siderite gravity separation method

The siderite gravity separation method is mainly suitable for single siderite with coarse-grained distribution. It can be processed by resuspension or jig beneficiation.

Strong magnetic separation method of siderite

Strong magnetic separation of siderite is mainly suitable for weak magnetic separation of siderite, using the different magnetic permeability of minerals to make it pass through the magnetic field, adsorb magnetic minerals, and pass through aggregates Funnel to collect it.

Siderite flotation method

The siderite flotation method is mainly suitable for mixed iron minerals containing siderite. Do not remove useful iron minerals.

Siderite beneficiation method

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