process of beneficiation plant iron ore mine equipments

iron ore beneficiation technology and process,gravity and magnetic separation | prominer (shanghai) mining technology co.,ltd

iron ore beneficiation technology and process,gravity and magnetic separation | prominer (shanghai) mining technology co.,ltd

Iron ore is one of the important raw materials for the production of pig iron and steel in the iron and steel industry. There are many types of iron ore. According to the magnetic properties of the ore, it is mainly divided into strong magnetism and weak magnetism. In order to improve the efficiency and production capacity of ore dressing and meet the smelting production requirements of iron and steel plants, appropriate and technology should be selected according to the different properties of different iron ore during beneficiation to achieve better beneficiation effects.

The composition of iron ore of a single magnetite type is simple, and the proportion of iron minerals is very large. Gangue minerals are mostly quartz and silicate minerals. According to production practice research, weak magnetic separation methods are often used to separate them. In a medium-sized magnetic separation plant, the ore is demagnetized and then enters the crushing and screening workshop to be crushed to a qualified particle size, and then fed to the grinding workshop for grinding operations. If the ore size after grinding is greater than 0.2 mm, one stage of grinding and magnetic separation process is adopted; if it is less than 0.2 mm, two stages of grinding and magnetic separation process are adopted. In order to increase the recovery rate of iron ore as much as possible, the qualified tailings may be scavenged and further recovered. In areas lacking water resources, a magnetic separator can be used for grinding and magnetic separation operations.

Because magnetite is easily depleted under the effect of weathering, such ores are generally sorted by dry magnetic separator to remove part of gangue minerals, and then subjected to grinding and magnetic separation to obtain concentrate.

The magnetite in the polymetallic magnetite is sulfide magnetite, and the gangue mineral contains silicate or carbonate, and is accompanied by cobalt pyrite, chalcopyrite and apatite. This kind of ore generally adopts the combined process of weak magnetic separation and flotation to recover iron and sulfur respectively.

Process flow: the ore is fed into the magnetic separator for weak magnetic separation to obtain magnetite concentrate and weak magnetic separation tailings, and the tailings enter the flotation process to obtain iron and sulfur.

The common process flow in actual production is: the raw ore is fed into the shaft furnace for roasting and magnetization, and after magnetization, it is fed into the magnetic separator for magnetic separation.

Gravity separation and magnetic separation are mainly used to separate coarse-grained and medium-grained weakly magnetic iron ore (20~2 mm). During gravity separation, heavy medium or jigging methods are commonly used for the gravity separation of coarse and very coarse (>20 mm) ores; spiral chutes, shakers and centrifugal concentrators for medium to fine (2~0.2mm) ores, etc. Reselect method.

In magnetic separation, the strong magnetic separator of coarse and medium-grained ore is usually dry-type strong magnetic separator; the fine-grained ore is usually wet-type strong magnetic separator. Because the grade of concentrate obtained by using one beneficiation method alone is not high, a combined process is often used:

Combination of flotation and magnetic separation: the magnetite-hematite ore of qualified particle size is fed into the magnetic separator for weak magnetic separation to obtain strong magnetic iron ore and weak magnetic tailings, and the tailings are fed into the magnetic separator for weak magnetic separation. In strong magnetic separation, strong magnetic separation tailings and concentrate are obtained, and the concentrate is fed to the flotation machine for flotation to obtain flotation iron concentrate tailings.

Combined gravity separation and magnetic separation: similar to the combined flow of flotation and magnetic separation, only the flotation is replaced by gravity separation, and the products are gravity separation concentrate and tailings. These two combined methods can improve the concentrate grade.

The above are mainly the common separation methods and technological processes of strong and weak magnetic iron ore. The composition of natural iron ore is often not so simple, so in actual production, it is necessary to clarify the mineral composition, and use a single sorting method or a joint sorting method according to the corresponding mineral properties. Only in this way can the beneficiation effect be improved.

Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.

beneficiation process and separation method,crushing grinding screening and classification | prominer (shanghai) mining technology co.,ltd

beneficiation process and separation method,crushing grinding screening and classification | prominer (shanghai) mining technology co.,ltd

The process of breaking the ore blocks with a particle size of 500-1500mm from the mine to a particle size of 5-25mm. The methods include crushing, crushing, chopping, etc., generally in three stages: coarse crushing, medium crushing, and fine crushing.

The particle size of the immersion dye in the ore of the beneficiation machinery and the separation method used are determined. Commonly used grinding equipments include rod mills, ball mills, self-grinding machines and semi-self-grinding machines. High energy consumption for grinding operations, usually about half of the total energy consumption for beneficiation

According to the size of the sieve surface, the material is divided into different particle size levels called sieving, which is often used to process materials with coarser particle size. According to the different sedimentation speed of particles in the medium (usually water), the materials are divided into different grades of equal reduction, called classification, and used for materials with smaller particle sizes. Screening and grading are to separate materials of suitable particle size during the crushing process, or divide the materials into different particle size levels for selection.

In order to avoid clogging of the crushing and screening equipment by the mud in the mud-containing mineral raw materials, ore washing is required. If the raw materials contain soluble useful or harmful ingredients, they must also be washed. Ore washing can be carried out in a scrubbing machine or in a screening and grading equipment.

After the crushing operation, the mineral raw materials enter the sorting operation to separate useful minerals from gangue, or separate useful minerals from each other. This is the main part of beneficiation. The sorting operations include heavy sorting, flotation,

In the medium (mainly water) flow, the difference in the specific gravity of the mineral raw material particles is used for classification. The suitable particle size range for re-election is wide, from a few hundred millimeters to less than one millimeter, with low beneficiation cost and less environmental pollution. Where the particle size of the mineral is within the above range and the specific gravity difference between the components is large, gravity selection is the most suitable. Sometimes, reselection (mainly heavy medium selection, jig selection, etc.) can be used to pre-select to remove part of the waste rock, and then use other methods to reduce the cost of mineral processing.

Use the difference of water wettability (hydrophobicity or hydrophilicity) on the surface of various mineral raw materials to distinguish. Usually refers to froth flotation. There are few natural hydrophobic minerals. Collectors are often added to the ore slurry to enhance the hydrophobicity of the minerals to be floated; various regulators are added to improve selectivity; foaming agents are added and aerated to generate bubbles to make hydrophobic The mineral particles are attached to the bubbles and float up and separate. Flotation can usually process materials smaller than 0.2-0.3mm. In principle, it can select various mineral raw materials. It is a widely used method. Flotation can also be used to separate smelting intermediate products, ions in solution, and treat wastewater.

Make use of the different magnetic properties of mineral particles to distinguish in a non-uniform magnetic field. Strong magnetic minerals (magnetite and pyrrhotite, etc.) are separated by a weak magnetic field magnetic separator; weak magnetic minerals (hematite, siderite, ilmenite, wolframite, etc.) are separated by a strong magnetic field magnetic separator Sorting. The structure of magnetic separator includes drum type, belt type, rotating ring type, disc type, induction roller type and so on. Magnetic pulleys are used to pre-select massive strong magnetic ore. The main development trend of magnetic separation is to solve the problem of recovery of fine-grained weakly magnetic minerals.

Use the difference in electrical properties of mineral particles to select in a high-voltage electric field. Mainly used to sort conductor, semiconductor and non-conductor minerals. According to the electric field, the electric separator can be divided into electrostatic concentrator, corona concentrator and composite electric field electric separator; according to the charging method of ore particles, it can be divided into contact electrified separator, corona electrified separator and friction electrified separator. The electrical separator has a narrow processing particle size range, low processing capacity, and raw materials need to be dried, so the application is limited; but the cost is not high, the separation effect is good, and the pollution is low; it is mainly used for the selection of coarse concentrates, such as separation white Tungsten ore, cassiterite, zircon, rutile, ilmenite, tantalum niobium, monazite, etc. Electric separation is also used for classification and dust removal of mineral raw materials. The development trend of electrical separation is to develop equipment with large processing capacity and high efficiency in selecting fine-grained materials.

Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.

iron ore processing,crushing,grinding plant machine desgin&for sale | prominer (shanghai) mining technology co.,ltd

iron ore processing,crushing,grinding plant machine desgin&for sale | prominer (shanghai) mining technology co.,ltd

After crushing, grinding, magnetic separation, flotation, and gravity separation, etc., iron is gradually selected from the natural iron ore. The beneficiation process should be as efficient and simple as possible, such as the development of energy-saving equipment, and the best possible results with the most suitable process. In the iron ore beneficiation factory, the equipment investment, production cost, power consumption and steel consumption of crushing and grinding operations often account for the largest proportion. Therefore, the calculation and selection of crushing and grinding equipment and the quality of operation management are to a large extent determine the economic benefits of the beneficiation factory.

There are many types of iron ore, but mainly magnetite (Fe3O4) and hematite (Fe2O3) are used for iron production because magnetite and hematite have higher content of iron and easy to be upgraded to high grade for steel factories.

Due to the deformation of the geological properties, there would be some changes of the characteristics of the raw ore and sometimes magnetite, hematite, limonite as well as other types iron ore and veins are in symbiosis form. So mineralogy study on the forms, characteristics as well as liberation size are necessary before getting into the study of beneficiation technology.

1. Magnetite ore stage grinding-magnetic separation process The stage grinding-magnetic separation process mainly utilizes the characteristics of magnetite that can be enriched under coarse grinding conditions, and at the same time, it can discharge the characteristics of single gangue, reducing the amount of grinding in the next stage. In the process of continuous development and improvement, the process adopts high-efficiency magnetic separation equipment to achieve energy saving and consumption reduction. At present, almost all magnetic separation plants in China use a large-diameter (medium 1 050 mm, medium 1 200 mm, medium 1 500 mm, etc.) permanent magnet magnetic separator to carry out the stage tailing removing process after one stage grinding. The characteristic of permanent magnet large-diameter magnetic separator is that it can effectively separate 3~0mm or 6~0mm, or even 10-0mm coarse-grained magnetite ore, and the yield of removed tails is generally 30.00%~50.00%. The grade is below 8.00%, which creates good conditions for the magnetic separation plant to save energy and increase production.

2.Magnetic separation-fine screen process Gangue conjoined bodies such as magnetite and quartz can be enriched when the particle size and magnetic properties reach a certain range. However, it is easy to form a coarse concatenated mixture in the iron concentrate, which reduces the grade of the iron concentrate. This kind of concentrate is sieved by a fine sieve with corresponding sieve holes, and high-quality iron concentrate can be obtained under the sieve.

There are two methods for gravity separation of hematite. One is coarse-grained gravity separation. The geological grade of the ore deposit is relatively high (about 50%), but the ore body is thinner or has more interlayers. The waste rock is mixed in during mining to dilute the ore. For this kind of ore, only crushing and no-grinding can be used so coarse-grained tailings are discarded through re-election to recover the geological grade.

The other one is fine-grain gravity separation, which mostly deals with the hematite with finer grain size and high magnetic content. After crushing, the ore is ground to separate the mineral monomers, and the fine-grained high-grade concentrate is obtained by gravity separation. However, since most of the weak magnetic iron ore concentrates with strong magnetic separation are not high in grade, and the unit processing capacity of the gravity separation process is relatively low, the combined process of strong magnetic separation and gravity separation is often used, that is, the strong magnetic separation process is used to discard a large amount of unqualified tailings, and then use the gravity separation process to further process the strong magnetic concentrate to improve the concentrate grade.

Due to the complexity, large-scale mixed iron ore and hematite ore adopt stage grinding or continuous grinding, coarse subdivision separation, gravity separation-weak magnetic separation-high gradient magnetic separation-anion reverse flotation process. The characteristics of such process are as follows:

(1) Coarse subdivision separation: For the coarse part, use gravity separation to take out most of the coarse-grained iron concentrate after a stage of grinding. The SLon type high gradient medium magnetic machine removes part of the tailings; the fine part uses the SLon type high gradient strong magnetic separator to further remove the tailings and mud to create good operating conditions for reverse flotation. Due to the superior performance of the SLon-type high-gradient magnetic separator, a higher recovery rate in the whole process is ensured, and the reverse flotation guarantees a higher fine-grained concentrate grade.

(2) A reasonable process for narrow-level selection is realized. In the process of mineral separation, the degree of separation of minerals is not only related to the characteristics of the mineral itself, but also to the specific surface area of the mineral particles. This effect is more prominent in the flotation process. Because in the flotation process, the minimum value of the force between the flotation agent and the mineral and the agent and the bubble is related to the specific surface area of the mineral, and the ratio of the agent to the mineral action area. This makes the factors double affecting the floatability of minerals easily causing minerals with a large specific surface area and relatively difficult to float and minerals with a small specific surface area and relatively easy to float have relatively consistent floatability, and sometimes the former has even better floatability. The realization of the narrow-level beneficiation process can prevent the occurrence of the above-mentioned phenomenon that easily leads to the chaos of the flotation process to a large extent, and improve the beneficiation efficiency.

(3) The combined application of high-gradient strong magnetic separation and anion reverse flotation process achieves the best combination of processes. At present, the weak magnetic iron ore beneficiation plants in China all adopt high-gradient strong magnetic separation-anion reverse flotation process in their technological process. This combination is particularly effective in the beneficiation of weak magnetic iron ore. For high-gradient strong magnetic separation, the effect of improving the grade of concentrate is not obvious. However, it is very effective to rely on high-gradient and strong magnetic separation to provide ideal raw materials for reverse flotation. At the same time, anion reverse flotation is affected by its own process characteristics and is particularly effective for the separation of fine-grained and relatively high-grade materials. The advantages of high-gradient strong magnetic separation and anion reverse flotation technology complement each other, and realize the delicate combination of the beneficiation process.

The key technology innovation of the integrated dry grinding and magnetic separation system is to "replace ball mill grinding with HPGR grinding", and the target is to reduce the cost of ball mill grinding and wet magnetic separation.

HPGRs orhigh-pressure grinding rollshave made broad advances into mining industries. The technology is now widely viewed as a primary milling alternative, and there are several large installations commissioned in recent years. After these developments, anHPGRsbased circuit configuration would often be the base case for certain ore types, such as very hard, abrasive ores.

The wear on a rolls surface is a function of the ores abrasivity. Increasing roll speed or pressure increases wear with a given material. Studs allowing the formation of an autogenous wear layer, edge blocks, and cheek plates. Development in these areas continues, with examples including profiling of stud hardness to minimize the bathtub effect (wear of the center of the rolls more rapidly than the outer areas), low-profile edge blocks for installation on worn tires, and improvements in both design and wear materials for cheek plates.

With Strip Surface, HPGRs improve observed downstream comminution efficiency. This is attributable to both increased fines generation, but also due to what appears to be weakening of the ore which many researchers attribute to micro-cracking.

As we tested , the average yield of 3mm-0 and 0.15mm-0 size fraction with Strip Surface was 78.3% and 46.2%, comparatively, the average yield of 3mm-0 and 0.3mm-0 with studs surface was 58.36% and 21.7%.

These intelligently engineered units are ideal for classifying coarser cuts ranging from 50 to 200 mesh. The feed material is dropped into the top of the classifier. It falls into a continuous feed curtain in front of the vanes, passing through low velocity air entering the side of the unit. The air flow direction is changed by the vanes from horizontal to angularly upward, resulting in separation and classification of the particulate. Coarse particles dropps directly to the product and fine particles are efficiently discharged through a valve beneath the unit. The micro fines are conveyed by air to a fabric filter for final recovery.

Air Magnetic Separation Cluster is a special equipment developed for dry magnetic separation of fine size (-3mm) and micro fine size(-0.1mm) magnetite. The air magnetic separation system can be combined according to the characteristic of magnetic minerals to achieve effective recovery of magnetite.

After rough grinding, adopt appropriate separation method, discard part of tailings and sort out part of qualified concentrate, and re-grind and re-separate the middling, is called stage grinding and stage separation process.

According to the characteristics of the raw ore, the use of stage grinding and stage separation technology is an effective measure for energy conservation in iron ore concentrators. At the coarser one-stage grinding fineness, high-efficiency beneficiation equipment is used to advance the tailings, which greatly reduces the processing volume of the second-stage grinding.

If the crystal grain size is relatively coarse, the stage grinding, stage magnetic separation-fine sieve self-circulation process is adopted. Generally, the product on the fine sieve is given to the second stage grinding and re-grinding. The process flow is relatively simple.

If the crystal grain size is too fine, the process of stage grinding, stage magnetic separation and fine sieve regrind is adopted. This process is the third stage of grinding and fine grinding after the products on the first and second stages of fine sieve are concentrated and magnetically separated. Then it is processed by magnetic separation and fine sieve, the process is relatively complicated.

At present, the operation of magnetic separation (including weak magnetic separation and strong magnetic separation) is one of the effective means of throwing tails in advance; anion reverse flotation and cation reverse flotation are one of the effective means to improve the grade of iron ore.

In particular, in the process of beneficiation, both of them basically take the selected feed minerals containing less gangue minerals as the sorting object, and both use the biggest difference in mineral selectivity, which makes the two in the whole process both play a good role in the process.

Based on the iron ore processing experience and necessary processing tests, Prominer can supply complete processing plant combined with various processing technologies, such as gravity separation, magnetic separation, flotation, etc., to improve the grade of TFe of the concentrate and get the best yield. Magnetic separation is commonly used for magnetite. Gravity separation is commonly used for hematite. Flotation is mainly used to process limonite and other kinds of iron ores

Through detailed mineralogy study and lab processing test, a most suitable processing plant parameters will be acquired. Based on those parameters Prominer can design a processing plant for mine owners and supply EPC services till the plant operating.

Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.

Related Equipments