Iron ore upgrading system

Abstract

The utility model provides an iron ore upgrading system. The system comprises an iron ore modification roasting device (1) and a cooling reduction device (2), low-quality iron ore is subjected to high-temperature modification through the iron ore modification roasting device (1), the iron ore subjected to high-temperature modification is reduced in the cooling process through the cooling reduction device (2), and the problem that FeO reacts with high-content silicon in the iron ore in the high-temperature modification process to form low-melting-point silicate minerals to cause ring formation of the rotary kiln is effectively solved; and meanwhile, the iron recovery rate of iron ore upgrading is also improved.

Description

Technical Field

[0001] The utility model relates to an iron ore treatment system, in particular to a system for improving the quality of iron ore, belonging to the technical field of iron ore smelting. Background Art

[0002] High-proportion pelletized iron ore blast furnace ironmaking and direct reduced iron + scrap short-process ironmaking are the common understandings in the development of iron and steel metallurgy to reduce energy consumption in the steel production process and achieve carbon emission reduction. With the continuous advancement of the carbon neutrality process and the continuous low-carbon adjustment of the iron and steel industrial structure, it is irresistible to increase the proportion of pelletized iron ore in the blast furnace burden of the long-process ironmaking and develop the direct reduction process of iron ore pellets. It will surely require an increasingly large pellet production capacity to provide ironmaking concentrate guarantee, and will continuously promote the rapid development of China's iron ore pellet industry. The demand for high-quality iron concentrate required in China every year will continue to increase. Therefore, the market demand for the production of high-quality iron concentrate for pellets in China is strong and the prospect is very broad.

[0003] In recent years, with the continuous rapid development of China's iron and steel metallurgy scale, domestic iron ore resources have been rapidly consumed, and there are fewer and fewer iron ores with higher quality. Moreover, with the further deepening of iron ore mining depth, the iron grade of the lower ore deposits is gradually decreasing. Whether in terms of output or quality, domestic iron ore resources are far from sufficient to support the development trend of the pellet industry scale.

[0004] The iron ore imported by China every year is mainly powder ore, which has problems such as many varieties, large property fluctuations, and continuous quality decline. Moreover, most of them cannot meet the pellet production requirements and can only be used as sintering raw materials. In particular, for the pellets used in the production of gas-based shaft furnace direct reduced iron, the TFe content is required to be above 65%. That is, when using magnetite as the raw material to produce gas-based shaft furnace direct reduced iron, the TFe content in the magnetite raw material needs to be above 67%. Therefore, to meet the development needs of China's pellet industry, imported iron ore needs to be further sorted and upgraded to meet the requirements of pellet raw materials for blast furnace and gas-based shaft furnace reduction. In the situation of the increasingly tight supply of domestic high-quality iron concentrate and the continuous rise of foreign high-grade iron concentrate prices, the selection of low-quality powder ore as the pellet production raw material has received more and more attention.

[0005] Taking low-quality limonite as an example, current research on using limonite fines for pellet production mainly focuses on two categories: directly preparing pellets from limonite and using iron concentrates obtained after magnetization roasting and magnetic separation of limonite for pellet production. Limonite is a hydrated iron oxide ore. During the roasting process, crystal water and free water are removed as the temperature rises, the porosity of ore particles increases, and with the removal of moisture, the iron grade will increase significantly. However, when preparing pellets from limonite, the green pellet bursting temperature is low and the strength of roasted pellets is low. When producing oxidized pellets using limonite and magnetite as raw materials, after mixing limonite and magnetite, it is easy to cause uneven distribution of FeO in the green pellets, and then uneven oxidation of the pellets during the oxidation roasting process, which is extremely likely to cause pellet dust, reduce the pellet strength, and during oxidation roasting, due to the relatively high silicon content in limonite, it is extremely easy to form low-melting-point silicate phases with FeO in magnetite, resulting in equipment ring formation.

[0006] In terms of magnetization roasting - grinding and magnetic separation of low-quality iron ores, taking low-quality limonite as an example, limonite is a mixture composed of goethite, lepidocrocite, akaganeite, ferrohydrite, silica hydrate, argillaceous, etc. The iron minerals are finely disseminated. Although crystal water can be removed and the mineral phase transformation of trivalent iron oxides to magnetite can be achieved during the magnetization roasting process, at relatively low magnetization roasting temperatures, the newly formed magnetite grains are difficult to grow and migrate and enrich, resulting in the still fine dissemination of iron-containing minerals after magnetization roasting, difficult dissociation from gangue minerals during the grinding process, and ultimately low iron grade of the magnetic separation concentrate. Rotary kiln magnetization roasting is a common magnetization roasting method. During the rotary kiln magnetization roasting process, a certain amount of coal needs to be added to the material as a reducing agent, and the material also needs to be heated to the reaction temperature by the flame at the kiln head. To maintain the stability of the flame, generally the temperature cannot be lower than 800 °C. To prevent over-reduction of iron oxides to wustite and affect the separation effect, the higher the temperature during the magnetization roasting process, the lower the suitable CO / (CO + CO2) ratio, and the greater the difficulty in controlling the CO partial pressure; in addition, a large amount of residual oxygen in the kiln atmosphere reacts with the coal in the material layer to release a large amount of heat, resulting in local high temperature in the material layer. In the part with local high temperature, not only will the iron oxides be over-reduced, but the large amount of FeO generated will also react with the high content of silicon in limonite to form low-melting-point silicate minerals, causing ring formation in the rotary kiln and reducing the iron recovery rate during the grinding and separation process at the same time. Summary of the Invention

[0007] In view of the technical problems that in the prior art, the upgrading of iron ore is usually completed in the same equipment, and the process conditions of the upgrading equipment are difficult to control, and problems such as ring formation are likely to occur, the utility model provides an iron ore upgrading system, which includes an iron ore modification roasting device (1) and a cooling reduction device (2); low-quality iron ore is subjected to high-temperature modification through the iron ore modification roasting device (1), and the iron ore after high-temperature modification passes through the cooling reduction device (2) and is reduced during the cooling process, effectively avoiding the problem of ring formation in the rotary kiln caused by the reaction of FeO with the high content of silicon in the iron ore to form low-melting-point silicate minerals during the high-temperature modification process, and at the same time improving the iron recovery rate of iron ore upgrading.

[0008] An iron ore upgrading system, which includes an iron ore modification roasting device and a cooling reduction device. The iron ore modification roasting device includes an original iron ore material inlet and a modified material outlet. The cooling reduction device includes a modified material inlet and a material outlet. The modified material outlet is connected to the modified material inlet.

[0009] Preferably, the system further includes a screening device. The screening device includes a coarse-grained material outlet and a fine-grained material outlet. The coarse-grained material outlet is communicated with the original iron ore material inlet. The fine-grained material outlet is communicated with the modified material inlet.

[0010] Preferably, the system further includes a grinding device. The material outlet of the cooling reduction device is communicated with the feed inlet of the grinding device.

[0011] Preferably, the system further includes a magnetic separation device. The discharge outlet of the grinding device is communicated with the feed inlet of the magnetic separation device. The magnetic separation device includes a magnetite material outlet and a tailing outlet.

[0012] Preferably, the iron ore modification roasting device is a rotary kiln.

[0013] Preferably, the cooling reduction device is a dry slow-cooling porous reduction cylinder. The dry slow-cooling porous reduction cylinder is a rotating cylinder structure, including a cylinder body and a driving mechanism. The driving mechanism is arranged outside the cylinder body and drives the cylinder body to rotate self. The cylinder body is provided with a modified material inlet and a material outlet. The outer wall of the cylinder body is provided with a cooling medium conveying pipe.

[0014] Preferably, a solid reducing agent inlet is further provided at the feed end of the dry slow-cooling porous reduction cylinder.

[0015] Preferably, a gas inlet is further provided on the dry slow-cooling porous reduction cylinder. The gas inlet is arranged at the feed end or the discharge end of the dry slow-cooling porous reduction cylinder.

[0016] Preferably, a reducing gas inlet is further provided on the dry slow-cooling porous reduction cylinder.

[0017] Preferably, the reducing gas inlet is arranged at the discharge end of the dry slow-cooling porous reduction cylinder.

[0018] Preferably, the cooling medium delivery pipe is spirally wound around the outer wall of the cylinder. The inlet of the cooling medium delivery pipe is arranged at the feeding end of the dry slow-cooling porous reduction cylinder. The outlet of the cooling medium delivery pipe is arranged at the discharging end of the dry slow-cooling porous reduction cylinder.

[0019] Preferably, lifting ribs are arranged on the inner wall of the cylinder of the dry slow-cooling porous reduction cylinder.

[0020] Preferably, the lifting ribs are spirally arranged on the inner wall of the cylinder.

[0021] Preferably, n lifting ribs are arranged on the inner wall of the cylinder of the dry slow-cooling porous reduction cylinder.

[0022] Preferably, n is 2 - 10, and preferably 3 - 6.

[0023] Preferably, the n lifting ribs are arranged in a parallel state on the inner wall of the cylinder, and adjacent lifting ribs do not cross each other.

[0024] Preferably, the cylinder of the dry slow-cooling porous reduction cylinder has a variable diameter structure, and the inner diameter of the discharging end of the cylinder is larger than that of the feeding end.

[0025] The grinding device is one of a ball mill, a vertical mill, a rod mill, and a roller mill.

[0026] In the present utility model, low-quality iron ore is subjected to high-temperature modification through an iron ore modification roasting device to obtain a hot modified material. The hot modified material is reduced during the cooling process through a cooling reduction device, and iron oxides are transformed into magnetic substances. Then, high-quality iron ore and tailings are obtained through grinding and magnetic separation.

[0027] Preferably, the low-quality iron ore is first screened through a screening device, and the part above 0.5 mm is subjected to high-temperature modification through the iron ore modification roasting device to obtain a hot modified material. The low-quality iron ore and the solid reducing agent obtained by screening - 0.5 mm or less are added to the cooling reduction device together.

[0028] In the present utility model, the low-grade iron ore includes limonite, hematite, specularite, siderite, phosphoric iron ore, pyrite, complex iron ore, red mud, iron-containing solid waste, etc.

[0029] Preferably, the iron ore modified roasting device is a rotary kiln. The high-temperature modification process is the roasting process of the rotary kiln, including oxidation roasting, sodium roasting, potassium roasting, phosphorylation roasting, sulfation roasting, calcification roasting, etc. The additives in the high-temperature modification process include sodium salts such as sodium hydroxide, sodium carbonate, sodium chloride, etc., potassium salts such as potassium hydroxide, potassium carbonate, potassium chloride, etc., phosphates such as phosphorus pentoxide, phosphoric acid, sodium phosphate, potassium phosphate, etc., sulfuric acid and sulfates, calcium salts such as calcium oxide, calcium hydroxide, calcium carbonate, calcium chloride, etc. The dosage range of the additives is 0-40%, the roasting temperature range is 400°C-1300°C, and the roasting time range is 0-180 min.

[0030] The hot modified material is reduced by a reducing agent during the slow cooling process using a cooling and reduction device: The equipment used is a dry slow-cooling porous reduction cylinder with co-controllable temperature and atmosphere. The outer wall of the dry slow-cooling porous reduction cylinder is equipped with cooling water pipes. Cold water is fed in from the high-temperature feeding end to quickly cool the high-temperature material. The hot water gradually flows to the low-temperature end, slowing down the cooling rate of the material in the low-temperature section.

[0031] Preferably, there are multiple continuous lifting screws on the inner wall of the dry slow-cooling porous reduction cylinder from the feeding end to the discharging section, and the screws do not cross each other, ensuring the rapid mixing of the material in the cylinder and sufficient contact with the reducing agent. The reducing agents include coal, biomass, coke, hydrogen, blast furnace gas, coke oven gas, converter gas, etc.

[0032] Preferably, when the hot modified material is cooled and reduced using a solid reducing agent, it is added to the cooling cylinder together with the low-quality iron ore with a particle size of less than -0.5 mm obtained by screening and the solid reducing agent. Under the action of the lifting screw in the dry slow-cooling porous reduction cylinder, it is quickly mixed and gradually cooled. During the cooling process, the reducing agent generates reducing gas to reduce the iron oxide in the iron ore to magnetic iron oxide. During the reduction process, an oxygen-free non-reducing gas is introduced from the cylinder body to adjust the reduction atmosphere partial pressure at different temperatures in the slow-cooling reduction section. The unreacted reducing gas during the cooling and reduction process is pumped into the modified rotary kiln for combustion.

[0033] Preferably, when the hot modified material is cooled and reduced using a gaseous reducing agent, it is added to the dry slow-cooling porous reduction cylinder together with the low-quality iron ore with a particle size of less than -0.5 mm obtained by screening. Under the action of the lifting screw, it is quickly mixed and gradually cooled. The reducing gas is introduced from the lower end of the cylinder, flowing countercurrent to the material. During the cooling process, the reducing gas reduces the iron oxide in the iron ore to magnetic iron oxide. During the reduction process, an oxygen-free non-reducing gas is introduced from the cylinder body to adjust the reduction atmosphere partial pressure at different temperatures in the slow-cooling reduction section. The unreacted reducing gas during the cooling and reduction process is pumped into the modified rotary kiln for combustion.

[0034] Using the iron ore upgrading system provided by the present invention, the hot modified material is transformed into a magnetic material after reduction, and the magnetic material is ground and separated by magnetic separation to obtain high-quality iron ore and tailings.

[0035] The iron ore upgrading system provided by the present utility model uses the method of the cooling water pipe outside the cylinder flowing in the same direction as the material. By controlling the water flow rate, the rapid cooling of the high-temperature material entering the cylinder can be controlled. The high-temperature cooling water gradually brings the heat to the low-temperature material at the rear end, reducing the cooling rate of the low-temperature material. At the same time, an oxygen-free non-reducing gas (input through the gas inlet), such as CO2 or H2O steam, is introduced at different positions inside the cylinder. By controlling the composition and flow rate of the oxygen-free non-reducing gas introduced in different sections, the reduction partial pressure of the reducing gas CO or H2 inside the cylinder is adjusted, so that the temperature and reducing gas partial pressure in different sections inside the cylinder meet the temperature and reducing gas partial pressure required for the stable existence of magnetite in the red or blue advantageous regions in the above figure.

[0036] In the present utility model, the dry slow-cooling porous reduction cylinder is of a rotating cylinder structure. The outer wall of the cylinder is provided with racks, and a gear is provided on the output shaft of the driving mechanism. The driving mechanism drives the cylinder to rotate self by the gear and the rack.

[0037] In the present utility model, the cooling medium delivery pipe is of a tubular structure. The cooling medium delivery pipe is spirally wound around the outer wall of the cylinder, playing the role of cooling the material outside the wall.

[0038] In the present utility model, a solid reducing agent inlet or a reducing gas inlet is provided on the dry slow-cooling porous reduction cylinder. The solid reducing agent or the reducing gas plays the role of reducing the material inside the cylinder. Combined with the cooling medium delivery pipe, the high-temperature modified material can simultaneously achieve the effects of cooling and reduction in the cooling and reduction device, avoiding the formation of material rings.

[0039] In the present utility model, lifting ribs are provided on the inner wall of the cylinder of the dry slow-cooling porous reduction cylinder. The lifting ribs are arranged on the inner wall of the cylinder by direct casting, playing the role of lifting the material, making the material inside the dry slow-cooling porous reduction cylinder cool evenly and fully contacting with the solid reducing agent or the reducing gas.

[0040] Preferably, the cylinder of the dry slow-cooling porous reduction cylinder is of a variable diameter structure, and the inner diameter of the discharge end of the cylinder is larger than the inner diameter of the feed end. This ensures the uniform dispersion of the material in the dry slow-cooling porous reduction cylinder and is also convenient for controlling the atmosphere pressure inside the dry slow-cooling porous reduction cylinder.

[0041] Compared with the prior art, the technical solution provided by the present utility model has the following beneficial technical effects:

[0042] 1. By using the iron ore upgrading system provided by the present utility model, low-quality iron ore is first subjected to high-temperature modification through an iron ore modification roasting device, where crystal water is removed at high temperature, and the transformation, aggregation, and growth of iron minerals are completed. Then, it is reduced to magnetic substances in a cooling and reduction device. The heating and reduction processes in the conventional magnetization roasting process are carried out step by step, solving the problem of ring formation caused by the same cavity and the same heat in the conventional rotary kiln magnetization process.

[0043] 2. By using the iron ore upgrading system provided by the present utility model, the heating and reduction are carried out step by step. The material heating process is completed in the roasting stage, and the magnetization reaction is carried out during the cooling process of the high-temperature material. This avoids the problem of ring formation caused by local high temperature due to flame heating. Moreover, by adding a reducing agent during the cooling process of the high-temperature material, the coordinated control of the magnetization temperature and the reduction atmosphere can be accurately achieved, avoiding the problem that the reduction atmosphere in the reactor with the same cavity and the same heat in the conventional magnetization process is difficult to control.

[0044] 3. The iron ore upgrading system provided by the present utility model preferably includes a screening device, which screens out fine-grained low-quality iron ore with a particle size of less than 0.5 mm in the low-quality iron ore powder and mixes it with the material before the cooling and reduction of the high-temperature modified material. The addition of fine-grained material can ensure the uniformity of the formation of magnetic substances during the reduction process and improve the grinding and magnetic separation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic structural diagram of an iron ore upgrading system of the present utility model;

[0046] Figure 2 It is a schematic structural diagram of an iron ore upgrading system of the present utility model, which further includes a screening device, a grinding device, and a magnetic separation device;

[0047] Figure 3 It is a schematic structural diagram of a dry slow-cooling porous reduction cylinder in an iron ore upgrading system of the present utility model;

[0048] Figure 4 It is a schematic structural diagram of the first dry slow-cooling porous reduction cylinder structure and the iron ore modification roasting device in the present utility model;

[0049] Figure 5 It is a schematic structural diagram of the second dry slow-cooling porous reduction cylinder structure and the iron ore modification roasting device in the present utility model;

[0050] Figure 6 It is a schematic structural diagram of the third dry slow-cooling porous reduction cylinder structure and the iron ore modification roasting device in the present utility model;

[0051] Figure 7 It is a schematic cross-sectional structure diagram of a dry slow-cooling porous reduction cylinder with lifting ribs provided therein in the present utility model;

[0052] Figure 8 Schematic diagram of the rotational state of the input material in the dry slow-cooling porous reduction cylinder of the present utility model;

[0053] Figure 9 Schematic diagram of the structure of the dry slow-cooling porous reduction cylinder of the present utility model with 2 lifting ribs;

[0054] Figure 10 Schematic diagram of the variable-diameter structure of the cylinder body of the dry slow-cooling porous reduction cylinder of the present utility model.

[0055] Reference numerals:

[0056] 1: Iron ore modification roasting device; 101: Raw iron ore material inlet; 102: Modified material outlet; 2: Cooling and reduction device; 201: Modified material inlet; 202: Material outlet; 3: Screening device; 301: Coarse particle material outlet; 302: Fine particle material outlet; 4: Grinding device; 5: Magnetic separation device; M: Dry slow-cooling porous reduction cylinder; M01: Cylinder body; M02: Driving mechanism; M03: Cooling medium delivery pipe; M04: Solid reducing agent inlet; M05: Gas inlet; M06: Reduction gas inlet; M07: Lifting rib. Detailed implementation manners

[0057] The technical solutions of the present invention will be illustrated by examples below. The scope of protection claimed by the present invention includes but is not limited to the following embodiments. Example 1

[0058] As Figure 1 shown, an iron ore quality improvement system, the system includes an iron ore modification roasting device (1) and a cooling and reduction device (2). The iron ore modification roasting device (1) includes a raw iron ore material inlet (101) and a modified material outlet (102). The cooling and reduction device (2) includes a modified material inlet (201) and a material outlet (202). The modified material outlet (102) is connected to the modified material inlet (201). Example 2

[0059] As Figure 2 shown, an iron ore quality improvement system, the system includes an iron ore modification roasting device (1) and a cooling and reduction device (2). The iron ore modification roasting device (1) includes a raw iron ore material inlet (101) and a modified material outlet (102). The cooling and reduction device (2) includes a modified material inlet (201) and a material outlet (202). The modified material outlet (102) is connected to the modified material inlet (201). The system further includes a screening device (3). The screening device (3) includes a coarse particle material outlet (301) and a fine particle material outlet (302). The coarse particle material outlet (301) is communicated with the raw iron ore material inlet (101). The fine particle material outlet (302) is communicated with the modified material inlet (201). Example 3

[0060] Repeat Example 2, except that the system further includes a grinding device (4). The material outlet (202) of the cooling and reduction device (2) is communicated with the feed inlet of the grinding device (4). Example 4

[0061] Repeat Example 3, except that the system further includes a magnetic separation device (5). The discharge outlet of the grinding device (4) is communicated with the feed inlet of the magnetic separation device (5). The magnetic separation device (5) includes a magnetite material outlet and a tailing outlet. The grinding device (4) is a ball mill. Example 5

[0062] Repeat Example 4, except that the iron ore modification roasting device (1) is a rotary kiln. Example 6

[0063] As Figure 3 shown, repeat Example 5, except that the cooling and reduction device (2) is a dry slow-cooling porous reduction cylinder (M). The dry slow-cooling porous reduction cylinder (M) is of a rotating cylinder structure and includes a cylinder body (M01) and a driving mechanism (M02). The driving mechanism (M02) is arranged outside the cylinder body (M01) and drives the cylinder body (M01) to rotate self. The cylinder body (M01) is provided with a modified material inlet (201) and a material outlet (202). The outer wall of the cylinder body (M01) is provided with a cooling medium delivery pipe (M03). Example 7

[0064] As Figure 4 shown, repeat Example 6, except that the feed end of the dry slow-cooling porous reduction cylinder (M) is further provided with a solid reducing agent inlet (M04). The dry slow-cooling porous reduction cylinder (M) is further provided with a gas inlet (M05). The gas inlet (M05) is arranged at the discharge end of the dry slow-cooling porous reduction cylinder (M). Example 8

[0065] As Figure 5 shown, repeat Example 6, except that the feed end of the dry slow-cooling porous reduction cylinder (M) is further provided with a solid reducing agent inlet (M04). The dry slow-cooling porous reduction cylinder (M) is further provided with a gas inlet (M05). The gas inlet (M05) is arranged at the feed end of the dry slow-cooling porous reduction cylinder (M). Example 9

[0066] As Figure 6 shown, repeat Example 6, except that the dry slow-cooling porous reduction cylinder (M) is further provided with a reducing gas inlet (M06). The reducing gas inlet (M06) is arranged at the discharge end of the dry slow-cooling porous reduction cylinder (M). Example 10

[0067] Example 6 was repeated, except that the cooling medium delivery pipe (M03) was spirally wound around the outer wall of the cylinder body (M01). The inlet of the cooling medium delivery pipe (M03) was arranged at the feeding end of the dry slow-cooling porous reduction cylinder (M). The outlet of the cooling medium delivery pipe (M03) was arranged at the discharging end of the dry slow-cooling porous reduction cylinder (M). Example 11

[0068] As Figure 7 and Figure 8 shown, Example 10 was repeated, except that lifting ribs (M07) were provided on the inner wall of the cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M). Example 12

[0069] As Figure 9 shown, Example 11 was repeated, except that the lifting ribs (M07) were spirally arranged on the inner wall of the cylinder body (M01). Example 13

[0070] As Figure 7 、 8 、10 shown, Example 11 was repeated, except that 4 lifting ribs (M07) were provided on the inner wall of the cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M). The 4 lifting ribs were arranged in parallel on the inner wall of the cylinder body (M01), and adjacent lifting ribs did not cross each other. Example 14

[0071] As Figure 9 shown, Example 11 was repeated, except that 2 lifting ribs (M07) were provided on the inner wall of the cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M). Example 15

[0072] As Figure 10 shown, Example 11 was repeated, except that the cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M) was of a variable diameter structure, and the inner diameter at the discharging end of the cylinder body (M01) was larger than that at the feeding end.

Claims

1. An iron ore upgrading system, characterized in that: The system includes an iron ore modified roasting device (1) and a cooling and reduction device (2); the iron ore modified roasting device (1) includes a raw iron ore material inlet (101) and a modified material outlet (102); the cooling and reduction device (2) includes a modified material inlet (201) and a material outlet (202); the modified material outlet (102) is connected to the modified material inlet (201).

2. The iron ore upgrading system according to claim 1, wherein: The system further includes a screening device (3); the screening device (3) includes a coarse particle material outlet (301) and a fine particle material outlet (302); the coarse particle material outlet (301) is communicated with the raw iron ore material inlet (101); the fine particle material outlet (302) is communicated with the modified material inlet (201).

3. The iron ore upgrading system according to claim 1, characterized in that: The system further includes a grinding device (4); the material outlet (202) of the cooling and reduction device (2) is communicated with the feed inlet of the grinding device (4).

4. The iron ore upgrading system according to claim 3, characterized in that: The system further includes a magnetic separation device (5); the discharge outlet of the grinding device (4) is communicated with the feed inlet of the magnetic separation device (5); the magnetic separation device (5) includes a magnetite material outlet and a tailing outlet.

5. The iron ore upgrading system according to any one of claims 1-4, characterized in that: The iron ore modified roasting device (1) is a rotary kiln.

6. The iron ore upgrading system according to any one of claims 1-4, characterized in that: The cooling and reduction device (2) is a dry slow-cooling porous reduction cylinder (M); the dry slow-cooling porous reduction cylinder (M) is a rotating cylinder structure, including a cylinder body (M01) and a driving mechanism (M02); the driving mechanism (M02) is arranged outside the cylinder body (M01) and drives the cylinder body (M01) to rotate self; the cylinder body (M01) is provided with a modified material inlet (201) and a material outlet (202); the outer wall of the cylinder body (M01) is provided with a cooling medium delivery pipe (M03).

7. The iron ore upgrading system according to claim 6, characterized in that: The feeding end of the dry slow-cooling porous reduction cylinder (M) is further provided with a solid reducing agent inlet (M04); and / or The dry slow-cooling porous reduction cylinder (M) is further provided with a gas inlet (M05); the gas inlet (M05) is arranged at the feeding end or the discharging end of the dry slow-cooling porous reduction cylinder (M).

8. The iron ore upgrading system according to claim 6, wherein: The dry slow-cooling porous reduction cylinder (M) is further provided with a reducing gas inlet (M06).

9. The iron ore upgrading system according to claim 8, characterized in that: The reducing gas inlet (M06) is arranged at the discharging end of the dry slow-cooling porous reduction cylinder (M).

10. The iron ore upgrading system according to claim 6, characterized in that: The cooling medium delivery pipe (M03) is spirally wound around the outer wall of the cylinder body (M01); the inlet of the cooling medium delivery pipe (M03) is arranged at the feeding end of the dry slow-cooling porous reduction cylinder (M); the outlet of the cooling medium delivery pipe (M03) is arranged at the discharging end of the dry slow-cooling porous reduction cylinder (M).

11. The iron ore upgrading system according to any one of claims 7-9, characterized in that: The cooling medium delivery pipe (M03) is spirally wound around the outer wall of the cylinder body (M01); the inlet of the cooling medium delivery pipe (M03) is arranged at the feeding end of the dry slow-cooling porous reduction cylinder (M); the outlet of the cooling medium delivery pipe (M03) is arranged at the discharging end of the dry slow-cooling porous reduction cylinder (M).

12. The iron ore upgrading system according to claim 6, wherein: The inner wall of the cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M) is provided with lifting ribs (M07).

13. The iron ore upgrading system according to any one of claims 7-9, characterized in that: The inner wall of the cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M) is provided with lifting ribs (M07).

14. The iron ore upgrading system according to claim 12, wherein: The lifting ribs (M07) are spirally arranged on the inner wall of the cylinder body (M01).

15. The iron ore upgrading system according to claim 13, characterized in that: The lifting ribs (M07) are spirally arranged on the inner wall of the cylinder body (M01).

16. The iron ore upgrading system according to claim 12, characterized in that: On the inner wall of the cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M), there are n material-lifting ribs (M07); n is 2 - 10.

17. The iron ore upgrading system according to claim 13, wherein: On the inner wall of the cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M), there are n material-lifting ribs (M07); n is 2 - 10.

18. The iron ore upgrading system according to claim 16 or 17, characterized in that: n is 3 - 6.

19. The iron ore upgrading system according to claim 16 or 17, characterized in that: The n material-lifting ribs are arranged in a parallel state on the inner wall of the cylinder body (M01), and adjacent material-lifting ribs do not cross each other.

20. The iron ore upgrading system according to claim 6, characterized in that: The cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M) is of a variable-diameter structure, and the inner diameter of the discharging end of the cylinder body (M01) is larger than that of the feeding end.

21. The iron ore upgrading system according to any one of claims 7-9, 12, 14-17, characterized in that: The cylinder body (M01) of the dry slow-cooling porous reduction cylinder (M) is of a variable-diameter structure, and the inner diameter of the discharging end of the cylinder body (M01) is larger than that of the feeding end.

22. The iron ore upgrading system according to claim 3, wherein: The grinding device (4) is one of a ball mill, a vertical mill, a rod mill, and a roller mill.

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