The most complete iron ore beneficiation process and technology

The most total iron ore beneficiation process and technology

The beneficiation process refers to the production process of the mined ore that meets the smelting requirements after various operations.

The beneficiation process mainly includes: ore crushing and sieving, ball mill grinding and classifier grading, mineral sorting (re-election, flotation and magnetic separation, etc.), mineral dehydration (concentration, filtration, drying, etc.).

Mineral processing equipment includes feeders, crushers , ball mills, classifiers, vibrating screens, shakers, magnetic separators, mixing drums, flotation machines and other equipment.

There are many types of iron ore, and different iron ore processes are also very different. The beneficiation process is to select different ore dressing methods according to the nature of different ores to achieve the best beneficiation effect.

The following is a common ore processing technology for the summary of iron ore:

First, magnetic separation ore

1. Single magnet ore

Most of the iron minerals in a single magnetite ore are magnetite. The ore dressing production history is the longest. Due to the simple ore composition, the weak magnetic separation method is often used.

For large and medium-sized magnetic separation plants, when the grinding particle size is larger than 0.2 mm, a grinding magnetic separation is often used; when less than 0.2 mm, two-stage grinding magnetic separation is used. If coarse tailing can separate qualified tailings, phase grinding magnetic separation is used.

In the water-deficient areas, dry-type grinding dry magnetic separation is used, and the magnetite-rich ore or lean magnetite is depleted. The gangue is generally removed by dry magnetic separation. The former obtains massive ore-rich ore; Choose to obtain concentrate.

In order to obtain high-grade concentrates, magnetite concentrates can be treated by reverse flotation or shock sieves. In order to improve the recovery rate, it can be further recycled by considering processes such as tailings re-election.

2, multi-metal containing magnetite

Multi-metal-containing magnetite ore or gangue silicate containing carbonate minerals, frequently with calendar Polygonum iron, cobalt ore pyrite or brass and the like apatite. Such ores also have more ore dressing production practices. Generally, a weak magnetic separation and flotation combined process is adopted, that is, iron is recovered by weak magnetic separation, and sulfide or apatite is recovered by flotation.

The principle process is divided into weak magnetic separation-flotation and flotation-weak magnetic separation. The two processes have different orientations of magnetite and sulfide. In the previous process, the continuous body mainly enters the iron concentrate; The latter process, mainly into the sulfide concentrate, so, under the same grinding particle size, the first floating magnetic process can obtain iron concentrate with lower sulfide content and sulfide concentrate with higher recovery rate.

Such ores are often self-fluxing and care should be taken to maintain the self-fluxing properties of the concentrate. There are high-containing, magnesium and some were isomorphic occur in the magnetite, iron difficult to separate by mechanical processing methods.

Second, weak magnetic iron ore

1. Single weak magnetic iron ore

Hematite ore, siderite ore, limonite ore (mirror iron)-side iron ore, including sedimentary metamorphic, sedimentary, hydrothermal and weathered deposits. This type of ore dressing production practice is less, due to the variety of minerals, a wide range of inlay size.

There are many mineral processing methods, and the commonly used methods can be divided into two types;

(1) Roasting magnetic separation

Roasting magnetic separation is one of the effective methods for selecting fine particles to fine particles (<0.02 mm) weak magnetic iron ore. When the minerals in the ore are complex and it is difficult to obtain good indicators by other methods, magnetization roasting magnetic separation should be used. 75~20mm lump ore has long-term production experience in shaft furnace reduction roasting; less than 20mm powder ore magnetization roaster has less practice. At present, fine ore is often selected by strong magnetic separation, re-election, flotation line method or joint process.

(2) Re-election, flotation, strong magnetic separation or a joint process.

Flotation is one of the commonly used methods for sorting fine particles to particulate weak magnetic iron ore. There are two principle processes of positive flotation and reverse flotation. The former applies to quartz hematite ore that does not contain easy-flowing gangue, and the latter applies to ore that is easy to float, and has production practices.

Re-election and strong magnetic separation are mainly used for sorting coarse (20~2 mm) and medium-weak weak magnetic iron ore, coarse and very coarse (>20 mm) ore for re-election of common medium or jigging Medium to fine-grained ore is a membrane re-election method such as a spiral concentrator, a shaker, a fan-shaped chute and a centrifugal concentrator. The strong magnetic separation of coarse and medium-sized ores is usually a dry induction roller type strong magnetic separator; fine particles The ore is commonly used as a strong magnetic separator for warm induction media. At present, because the fine magnetic ore concentrate of fine-grained ore is not high in grade, and the re-election unit has low processing capacity, it often forms a combined process of strong magnetic-re-election, discards a large number of qualified tailings with strong magnetic separation, and then re-selects further Handle strong magnetic concentrates to improve grade.

2. Multi-metal weak magnetic iron ore

Mainly hydrothermal and sedimentary hematite or siderite containing phosphorus or barium sulfide. Such ores generally recover iron minerals by re-election, flotation, strong magnetic separation or a combination thereof, and recover phosphorus or sulfide by flotation.

The hydrothermal type apatite-containing hematite ore and copper-containing sulphur iron ore can be floated.

Sedimentary phosphorus-containing hematite ore, although it can be separated from iron by flotation, is often difficult to integrate with phosphorus concentrate, and the iron recovery rate is much reduced. It can be considered to remove the large-grained gangue, smelt the high-phosphorus pig iron, and then recover the steel slag phosphate fertilizer.

The iron cap of weathered deposits contains limonite ore of non-ferrous metals, often accompanied by copper, arsenic , tin and other accompanying fractions without separate minerals. It is difficult to separate from iron by beneficiation method, and chlorination roasting is being studied. Red earth type nickel- chromium- cobalt-molybdenite-bearing medium, with no separate minerals, and methods such as roasting ammonia leaching and separation magnetic separation are under study.

Third, the magnet - red (Ring) iron ore

1. Single magnet - Chi (Ring) iron ore

The iron minerals in the ore are magnetite and hematite or siderite, which are mostly fine-grained; the gangue is mainly quartz, and some contain more iron silicate. The proportion of magnets in the ore varies, from the surface of the deposit to the depth of the deposit.

There are two common methods for this type of ore:

(1) weak magnetic separation and re-election, flotation, strong magnetic separation

The series process of recovering magnetite by weak magnetic separation and recovering weak magnetic iron mineral by re-election, flotation or strong magnetic separation has been used more recently. In this process, weak magnetic separation-flotation, flotation-weak magnetic separation and weak magnetic separation-reselection have been used for production; weak magnetic separation-strong magnetic separation and weak magnetic separation-strong magnetic separation-reselection are also Building a factory. Through production practice, the weak magnetic separation-flotation process tends to put the flotation before the weak magnetic separation, the production is more stable and easy to operate and manage; for the weak magnetic separation-re-election process, it tends to change to weak magnetic separation. - Strong magnetic or weak magnetic selection - strong magnetic selection - reselection process.

(2) Magnetization roasting magnetic separation method or parallel flow with other methods

Similar to the magnetization roasting magnetic separation of a single weak magnetic iron ore, but in the parallel flow of magnetization roasting magnetic separation and other beneficiation methods, the fine ore is combined with weak magnetic separation and other methods. This parallel process has production practices. In addition, the series process of roasting magnetic separation and other methods has been studied, that is, the roasting magnetic separation concentrate is selected by flotation, re-election or rotating magnetic field magnetic separation to further improve the concentrate grade, which has not been used yet. produce.

2, containing multi-metal magnets - red (Ring) iron ore

The iron minerals in this type of ore are mainly magnetite and hematite or siderite, medium to fine grain inlay; gangue minerals are silicate and carbonate minerals or fluorite; Pyrite, chalcopyrite and rare earth minerals.

The ore dressing method of such ore is the most complicated in iron ore. Generally, the combined process of weak magnetic and other methods is adopted, that is, magnetite is recovered by weak magnetic separation; weak magnetic iron is recovered by re-election, flotation or strong magnetic separation. Minerals and flotation are used to recover companion fractions.

Weak magnetic separation-flotation-strong magnetic separation, weak magnetic separation-strong magnetic separation-flotation and weak magnetic separation-re-election-flotation processes are being studied. For rare earth-containing mixed iron ore, when hematite is used as a large amount in iron ore, there is also a reduction roasting magnetic separation-flotation process, reduction roasting magnetic selection of iron minerals, and rare earth minerals after reduction roasting Flotation has improved the indicator.

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