WO2021232489A1

WO2021232489A1 - System for treating steel tailings using dry method

Info

Publication number: WO2021232489A1
Application number: PCT/CN2020/093884
Authority: WO
Inventors: 程福安; 孙建新; 胡泽武
Original assignee: 莱歇研磨机械制造(上海)有限公司; 程福安; 孙建新
Priority date: 2020-05-21
Filing date: 2020-06-02
Publication date: 2021-11-25
Also published as: CN111604131B; CN111604131A

Abstract

Provided in the present invention is a system for treating steel tailings using a dry method, comprising: a roller mill completing repeated dissociation and pre-separation of the steel tailings and separating out minerals rich in iron particles and other light materials; a gravity separator connected to the roller mill to separate out heavy particles rich in iron particles; a first magnetic separator connected to the gravity separator to separate out the iron particles from the heavy particles rich in iron particles; a three-stage mass separator provided at the upper portion of the roller mill to separate out heavy particles, light particles, and steel slag micro-powder from the other light materials according to the weight; a second magnetic separator connected to the three-stage mass separator to separate out fine iron powder rich in magnetic iron oxide from the heavy particles; and a third magnetic separator connected to the three-stage mass separator to separate out iron-rich RO phase minerals from the light particles. According to the system for treating the steel tailings in the present invention, repeated grinding dissociation and pre-separation can be performed on the steel tailings, so that 100% of the steel tailings are converted into the iron particles, the fine iron powder, the iron-rich RO phase minerals, and the steel slag micro-powder.

Description

Dry-process steel tailings treatment system

Technical field

The present invention relates to the field of industrial waste treatment, and more specifically, to a high-efficiency and intensive dry-process steel tailings treatment system that classifies and processes steel tailings waste generated in the process of iron and steel smelting.

Background technique

Steel slag is a by-product of the steelmaking process, and its output is 15% of crude steel output. The annual output of steel slag in my country is about 150 million tons, and the steel tailings produced after crushing and iron processing are also more than 1.3 tons. At present, the utilization rate of steel slag in my country is low and the utilization effect is poor. Every year, more than 100 million tons of steel tailings are discarded to form a slag mountain, which seriously threatens the safety of the ecological environment and has increasingly become a chronic disease for the survival and development of the steel industry. Therefore, it is an urgent task to develop efficient and clean steel tailings waste treatment equipment and processes, realize the resource utilization of steel tailings, and eliminate the environmental pollution caused by the storage of steel tailings. The resource treatment of steel tailings can not only produce The huge social benefits, while also producing huge economic benefits, are of great significance to the healthy development of the iron and steel industry.

According to the available directions, the main mineral components of steel tailings can be divided into two categories:

1) Active minerals similar to Portland cement clinker:

Calcium silicate, calcium ferrite, calcium ferrite aluminate, free calcium oxide, total active mineral content is about 55%;

2) Iron-rich inert minerals:

Iron particles Fe, magnetic iron oxide Fe ₃ O ₄ , RO phase MgO, MnO and FeO, of which: iron particles Fe account for about 2-3%, magnetic iron oxide Fe ₃ O ₄ account for about 4.5-7.5%, RO phase about 35%, the total iron-rich inert mineral content is about 45%.

How to dissociate steel tailings waste and sort out different minerals to convert them into high-value products has always been the direction of this technical field.

Chinese invention patent CN102688880B discloses a method for efficient recovery and reselection of steel slag, in which the iron content in the steel tailings after multi-stage crushing and iron removal is reduced to 10-25% when the iron in the steel slag is extracted. . In the second half of the process, a two-stage combined grinding system of "roller mill (or roller press) pre-grinding-magnetic separation-ball mill final grinding" is used for the treatment of steel tailings. The fine iron particles remaining in the steel slag are extracted by magnetic separation between the two grindings, and a small amount of iron powder is selected while producing the steel slag powder.

The disadvantages of the above method are:

1) Two-stage grinding is used, and ^{the particle size of 150m 2} /kg is selected as the iron concentrate. The corresponding particle diameter should be at the level of 0.1-0.2mm, which is much larger than the RO phase about 30μm, which is almost impossible to dissociate RO phase minerals are extracted, so that the selected objects are limited to the iron particles remaining in the steel tailings and some large particles of magnetic iron oxide. The iron removal rate of the steel tailings is too low;

2) The extraction rate of iron minerals is too low, and the produced steel slag powder contains too many inert minerals, mainly RO phase, so that it is difficult to improve the activity of the steel slag powder;

3) Due to the existence of a large amount of iron-rich RO, the material has poor grindability. In addition, the use of a ball mill that is not suitable for fine grinding as a final grinding equipment produces ^{steel slag powder with a fineness of more than 420m 2} /kg, and the power consumption of the system is too high. Even lose its economy.

Chinese invention patent CN106755650B discloses a process for producing high-activity steel slag powder and inert mineral products from steel slag. The process is a "six-step" steel tailings resource treatment process, that is, "dry grinding-pneumatic separation". -Dry magnetic separation-wet grinding-wet magnetic separation-dehydration".

One of the characteristics of the process: ^{a semi-finished product with a specific surface area of 300m 2} /kg is produced through primary grinding, and then high-activity steel slag powder and coarse powder are obtained by pneumatic separation, and then the coarse powder is magnetically separated by a dry method to select inert Coarse concentrate with a mineral content greater than 67%. This means that when the above process is used, the small iron particles, iron oxide minerals and RO in the steel tailings must be ground to 300m ² /kg, with a particle size of about 20μm, which will cause problems:

1) This process cannot use ordinary roller mills—when ordinary roller mills are used to grind steel tailings, the hard-to-grind iron-rich minerals will be continuously enriched on the grinding disc during the grinding process, and the grinding will be repeated for a long time. It will also cause these hard-to-grind iron-rich minerals and the equipment body to produce magnetism, which will adhere to the surface of the grinding disc and grinding roller by the magnetic force, causing the grinding function of the equipment to fail;

2) High power consumption in the production process of semi-products—considering that the grindability of steel tailings is more difficult than that of cement clinker, the enrichment of iron-rich minerals, and the limited selection of primary grinding equipment, the production of 300m ² /kg semi-product power The consumption may be as high as 50kw/h or more;

3) Selecting high-active steel slag powder with a fineness of usually greater than 420m ² ^{/kg from the 300m 2} /kg semi-products, the output rate will be very low or difficult to achieve.

The second feature of the process: use wet ball milling to continue to grind and magnetically select "coarse fine powder with inert content greater than 67%", grind to 65μm particles, and then wet magnetic separation to obtain iron grade T-Fe ≥ 55% Of high-grade inert mineral products and cement iron raw materials. The disadvantages and problems of this method are:

1) The extraction rate of RO phase is low—the diameter of 65μm material and the existence of 30μm particles that are twice as large as the RO phase. The particle dissociation is severely insufficient, which makes it impossible to effectively extract the iron-rich RO phase. The result is the product "inert minerals". "The iron grade is only 55%, the output rate is low, and the iron in the steel tailings still remains in a large amount of "cement iron raw materials";

2) Cement iron raw materials are difficult to use-as we all know, the concentration of iron and steel production is far greater than that of cement clinker production. The former is very few and the latter is everywhere. This means that the cement iron raw materials obtained by using this technology are useless Wuzhidi loses its commercial value due to its low value and long transportation distance. What is obtained is a mud cake with a water content of 8% and a particle size of less than 65μm, which causes more environmental pollution;

3) Wet grinding and wet beneficiation is a technology that has existed for a century. It is backward, low in efficiency, and environmentally unfriendly. It is mostly used in iron mining mines far away from people. In terms of the place of production), it is difficult to accept;

4) The patented technology must pass through dry grinding equipment (roller mill or roller press), powder separator, dry primary magnetic separator, wet grinding equipment (baseball mill), wet magnetic separator, etc. "Six steps" can be completed, the production path is long, especially wet grinding and wet selection, which makes the process too complicated and high power consumption;

5) Product (1) The amount of fine steel slag powder is small; product (2) The iron grade of high-grade inert mineral products is only T-Fe 55%, which is mainly the elemental iron in steel slag, magnetic iron oxide, and not much RO phase , The grade can only reach the fifth grade of YB/T4267; product (3) the availability of cement and iron raw materials is very low, and there is secondary pollution;

Due to the above-mentioned technical defects or application problems, there has been no practical application case for this technology in the past 3 years.

In summary, whether it is "a method for efficient recovery and reselection of steel slag" (CN102688880B), or "a process for producing highly active steel slag powder and inert mineral products from steel slag" (CN106755650B), both are used in the treatment of steel tailings Two mills (roller press or roller mill) + (ball mill or rod mill) system have been installed, and there is less extraction of iron-rich minerals, low iron grade, insufficient activity of steel slag powder, and secondary waste And the electricity consumption is as high as 60-75kWh/t, the production cost is high, and the product value is limited, making it difficult to promote the use of steel tailings treatment technology. Therefore, finding a set of economical and effective steel tailings treatment methods, turning waste into treasure, and turning the discarded "steel tailings into resources" is a difficult topic that urgently needs to be resolved in my country's iron and steel industry.

Summary of the invention

In order to solve the above-mentioned problems, the present invention provides a dry-process steel tailings treatment system that can perform repeated grinding, dissociation and preselection of steel tailings. The system converts 100% of the steel tailings into iron particles, iron fine powder, Iron-rich RO phase minerals and steel slag powder.

The dry-process steel tailings processing system according to the present invention includes: a roller mill including a grinding disc for receiving and grinding steel tailings, an iron-rich mineral sorting device located on the grinding disc, and a grinding disc. The pneumatic separator connected to the iron-rich mineral sorting device. The iron-rich mineral sorting device is used to discharge the iron-rich minerals in the particles after the grinding disc from the grinding disc. The pneumatic separator is used to receive the grinding disc. The material is discharged and the iron-rich minerals and other light materials are separated through the wind field with varying strength and discharged from the roller mill; the gravity separator is connected to the roller mill and receives from the roller The iron-rich minerals discharged from the mill to separate the iron-rich heavy particles, and the remaining mineral particles are returned to the roller mill for repeated grinding, dissociation and separation; the first magnetic separator, the second A magnetic separator is connected to a gravity separator to separate iron particles from iron-rich heavy particles through magnetic separation, and return the remaining mineral particles to the roller mill for repeated grinding, dissociation and separation; A quality sorting machine, the three-stage quality sorting machine is set on the upper part of the roller mill to receive other light materials discharged from the roller mill, and sorts the other light materials into heavy particles, light particles and steel slag powder according to their weight ; A second magnetic separator, the second magnetic separator is connected to a three-stage mass separator and receives heavy particles for use in separating fine iron powders rich in magnetic iron oxide from the heavy particles through magnetic separation, and Return the remaining mineral particles to the roller mill for repeated grinding, dissociation and separation; and a third magnetic separator, which is connected to a three-stage mass separator and receives light particles for passing through the magnetic The iron-rich RO phase minerals are separated from the light particles, and the remaining mineral particles are returned to the roller mill for repeated grinding, dissociation and separation.

According to an embodiment of the present invention, the iron-rich mineral sorting device may further include: a base grinding ring, the base grinding ring is arranged on the grinding disc to bear the grinding force; a material bed holding ring, the material bed holding ring is fixed to The base grinding ring has a height higher than that of the base grinding ring, and the material bed holding ring is connected to the grinding disc; and the iron-rich mineral release ring, which is fixed on the material bed holding ring and is formed for discharging A plurality of discharge channels rich in iron grain minerals, each of the plurality of discharge channels has a top opening connected to the inner cavity of the roller mill and a bottom opening connected to the bed holding ring.

According to an exemplary embodiment, each of the plurality of discharge channels may have a right-angled trapezoid shape, the lower bottom side of which is longer than the upper bottom side.

Further, the angle formed by the oblique waist of the right-angled trapezoid shape and the bottom edge may be in the range of 85-92°.

Optionally, the top opening may have a width in the range of 3-8 mm, and the bottom opening may have a width in the range of 8-15 mm.

Optionally, the distance between the centers of the top openings of two adjacent discharge channels may be in the range of 350-420 mm.

In addition, preferably, the surface of the base grinding ring in contact with the material can be treated with metal wear-resistant surfacing.

Optionally, the material bed holding ring can be fixed to the grinding disc by a bolt connection.

According to another embodiment of the present invention, the pneumatic separator may further include: a plurality of sorting swirl blades, one end of each of the plurality of sorting swirl blades is fixed to the shell of the roller mill and Are arranged spaced apart from each other, and each of the sorting swirling blades is inclined with respect to the horizontal direction; a plurality of flow field intensity distribution plates, each of the plurality of flow field intensity distribution plates is spaced apart from each other and arranged along the vertical direction , And one end of each flow field intensity distribution plate is connected to multiple sorting swirl blades, and the other end is free to swing, thereby dividing the material discharge area into a strong wind area, a medium wind field intensity area and a weak wind area; and a return plate , The return flow plate is arranged above the plurality of sorting swirl vanes and the plurality of flow field intensity distribution plates, and one end is fixed to the shell, and the return flow plate is an arc-shaped plate extending upward at an angle with respect to the horizontal direction .

Optionally, the angle formed by the sorting swirl blade and the horizontal direction may be in the range of 50-70°.

In addition, optionally, the angle formed by the return plate with respect to the horizontal direction may be in the range of 45-65°.

According to another embodiment of the present invention, the three-stage mass sorting machine may further include a power sorting rotor, guide blades and strong swirling blades arranged in order from the inside to the outside with the same center, wherein the strong swirling blades and the guide blades are fixed on The upper part of the shell of the roller mill, and the strong swirling blades are used to sort out heavy particles, the guide blades are used to sort out light particles, and the power sorting rotor is used to sort out steel slag powder.

Further, the power sorting rotor can be connected with an electric motor and a reducer to provide rotary power for the power sorting rotor.

Compared with the prior art, the dry-process steel tailings treatment system according to the present invention has the following beneficial effects:

1) According to the classification and selection of the chemical composition and physical properties of the minerals with different values in the steel tailings, the produced T-Fe>85% iron particles, T-Fe 60-65% magnetic iron oxide iron powder and T-Fe 40-45% RO phase iron refined powder products, compared with a single T-Fe 55% iron refined powder, the recovery rate of iron minerals is large, and the economic value of the product is higher;

2) The iron recovery rate of the three products reaches 30% in total, the iron of the main product steel slag powder is reduced to less than 12%, and its activity is greatly increased to more than 30%, ensuring that the quality is better than the first grade steel slag powder of GB/T20491;

3) In the production process, one host completes grinding, dissociation and multiple sorting, the system is efficient and simple, and the unit consumption of the system is reduced by more than 25%;

4) Full dry production, no water consumption; no renewable waste or low-value substances are produced.

Therefore, the dry-process steel tailings treatment system according to the present invention realizes the advanced treatment and high-efficiency utilization of steel tailings waste. The production process is simple, the equipment is advanced and mature, the production process is energy-saving and environmentally friendly, and it protects the ecological environment while also generating a huge economy. benefit.

Description of the drawings

The above and other aspects and features of the present invention will be clearly presented from the following description of the embodiments in conjunction with the accompanying drawings, in which:

Fig. 1 is a schematic block diagram showing the structure of a dry-process steel tailings treatment system according to the present invention;

Figure 2 is a partial structural diagram of a roller mill according to an embodiment of the present invention;

3A is a cross-sectional view taken along the direction V in FIG. 2;

3B is a cross-sectional view taken along the U direction in FIG. 2;

3C is a cross-sectional view taken along the W direction in FIG. 2; and

4A and 4B are schematic diagrams showing a partial structure of a pneumatic separator according to another embodiment of the present invention.

Detailed ways

The illustrative and non-limiting embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and the dry-process steel tailings treatment system according to the present invention will be further described.

Fig. 1 is a schematic block diagram showing the structure of a dry-process steel tailings treatment system according to the present invention. The dry-process steel tailings treatment system includes a roller mill 1, a gravity separator 2, a first magnetic separator 3. The three-stage mass separator 4, the second magnetic separator 5 and the third magnetic separator 6. Hereinafter, the structure of the dry steel tailings treatment system according to the present invention will be explained in detail with reference to FIG. 1.

According to the present invention, the roller mill 1 is used for repeated grinding, dissociation and pre-sorting of incoming steel tailings and intermediate mineral particles produced during the sorting process (ie, the first sorting of steel tailings waste) . Specifically, the roller mill 1 may include a grinding disc 11 for receiving and grinding steel tailings, an iron-rich mineral sorting device 12 located on the grinding disc 11, and respectively connected to the grinding disc 11 and the iron-rich mineral sorting device 12 The pneumatic separator 13 (as shown in Figure 2). The iron-rich mineral sorting device 12 is used to discharge iron-rich minerals in the particles ground by the grinding disc 11 from the grinding disc. The pneumatic separator 13 is used to receive the discharged materials from the grinding disc 11, and sort out the heavier iron-rich minerals and other light materials through the wind field with varying strength and discharge them from the roller mill. After being dissociated by roller milling, the steel tailings particles are reduced from the initial 10mm to about 10μm. In the process of particle size reduction, the monomer dissociation of various mineral particles is completed, and iron of more than 300μm is released. Granules, 80-500μm iron-rich minerals, 20μm-80μm iron-rich RO phase minerals and active minerals.

The gravity separator 2 is connected to the roller mill 1 and receives the iron-rich minerals discharged from the roller mill in time, and then sorts the iron-rich heavy particles according to the mass size, that is, the first waste of steel tailings. Secondary sorting. The remaining lighter mineral particles are returned to the roller mill 1 by the gravity separator for repeated grinding, dissociation and separation.

The first magnetic separator 3 is connected to the gravity separator 2, and magnetic separation is used to separate iron particles from the iron-rich heavy particles, for example, iron particles with an iron grade of T-Fe≥85%, thereby producing the first After processing the products and complete the second sorting and first extraction of steel tailings waste, the iron recovery rate is as high as 8%. The remaining mineral particles are returned to the roller mill 1 by the first magnetic separator 3 for repeated grinding, dissociation and sorting. Because the iron-rich mineral particles are discharged from the roller mill in time, the electric energy consumed by the roller mill will not be consumed on the iron-rich mineral particles that are difficult to grind in the steel tailings, so the grinding power consumption can be reduced. More than 25%.

The three-stage mass sorting machine 4 is arranged on the upper part of the roller mill 1 to receive other light materials discharged after the roller mill 1 is ground, dissociated and sorted. For example, a three-stage mass sorter can be formed integrally with a roller mill. The three-stage mass sorting machine 4 sorts the other light materials into heavy particles, light particles and steel slag powder (for example, the first grade steel slag powder with a quality better than GB/T20491) according to different weights, thereby completing steel tailings The third sorting, fourth sorting and fifth sorting.

The second magnetic separator 5 is connected to the three-stage mass separator 4 and receives the heavy particles sorted by it, so as to separate the iron fine powder rich in magnetic iron oxide from the heavy particles by magnetic separation, For example, T-Fe is 60-65% of the fine iron powder, so as to complete the second extraction of steel tailings, and the iron recovery rate can reach 10%. The remaining mineral particles are returned to the roller mill 1 by the second magnetic separator 5 for repeated grinding, dissociation and separation.

The third magnetic separator 6 is connected to the three-stage mass separator 4 and receives the light particles sorted by the third-stage mass sorter 4 for separating iron-rich RO phase minerals, such as T-Fe, from the light particles by magnetic separation. With 40-45% of iron-rich RO phase minerals, the third extraction of steel tailings is completed, and the iron recovery rate reaches 12%. The remaining mineral particles are returned to the roller mill 1 by the third magnetic separator 6 for repeated grinding, dissociation and separation.

The steel tailings treatment system with the above-mentioned structure according to the present invention is a dry-process steel tailings intensive treatment system. In the steel tailings processing system, the roller mill completes the repeated dissociation of the steel tailings waste particles and the first sorting; the gravity sorter completes the second sorting for the iron particles; and the three-level quality sorting The sorting machine completes the third, fourth and fifth sorting, and sorts out heavy particles, light particles and steel slag powder (product 1). In order to select high-quality products, three magnetic separators with different magnetic field strengths are selected according to the magnetic size of the respective processing objects to separate the iron-rich minerals from the gravity separator, the heavy particles from the three-stage mass separator and the Light particles are subjected to magnetic separation, and iron particles (product 2), iron concentrates rich in magnetic iron oxide (product 3) and iron-rich RO iron concentrates (product 4) are selected to achieve three extractions of iron minerals. After iron selection, the remaining intermediate minerals that have not reached the fineness of the steel slag powder will be returned to the roller mill for re-grinding, dissociation and sorting. Therefore, the dry steel tailings processing system according to the present invention realizes five sorting, three extractions, repeated grinding and dissociation, instant sorting and real-time extraction, which can not only grind dissociated minerals efficiently and thoroughly, and accurately subdivide products, Deep recovery of iron minerals, 100% resource utilization, and intensive equipment, simple process, dry production, energy saving and environmental protection. Compared with the existing technology, the processing system according to the present invention is an efficient and intensive steel tailings processing system.

The comparison between the steel slag powder obtained by the dry-process steel tailings treatment system according to the present invention and the national standard is shown in Table 1 below:

To	GB/T20491GB/T20491	本专利This patent
比表面积(m ²/kg) Specific surface area (m ² /kg)	≥350≥350	≥400≥400
活性指数(％)Activity index (%)	To	To
7天7 days	≥65≥65	≥72≥72
28天28 days	≥80≥80	≥82≥82

Table 1

The comparison of the characteristics of iron particles, iron concentrates and iron-rich RO phase products obtained by the dry-process steel tailings treatment system according to the present invention and the existing iron ore is shown in Table 2 below:

To	To	YB/T4267YB/T4267	本专利This patent
铁颗粒Iron particles	一级铁品位T-FeFirst grade iron grade T-Fe	≥64≥64	≥85≥85
铁精粉Iron powder	三级铁品位T-FeGrade 3 iron grade T-Fe	60-6260-62	60-6560-65

Table 2

It can be seen from Table 1 and Table 2 above that the processing system according to the present invention can obtain high-quality products. The iron grade of the iron-rich RO phase product is T-Fe 40-45%, and the total amount of CaO and MgO in its chemical composition is 30%. It is an alkaline iron powder that can be used for smelting. In addition, the system power consumption of the processing system according to the present invention is small (≤50kWh/t).

According to an embodiment of the present invention, the iron-rich mineral sorting device 12 may further include a base grinding ring 121, a bed holding ring 122, and an iron-rich mineral releasing ring 123, as shown in FIGS. 2 and 3A. Specifically, the base grinding ring 121 is arranged on the 13 grinding disc to carry the grinding force in the grinding zone. In the present invention, the grinding roller 15, the grinding disc 11 and the iron-rich mineral sorting device 12 constitute a grinding zone. The surface of the base grinding ring 121 that is in contact with the material can be treated with metal wear-resistant surfacing, for example, so that the surface hardness can meet HRC62. The bed holding ring 122 is connected to the grinding disc 13, for example, is fixed to the grinding disc 13 by a bolt connection. In addition, the material bed holding ring 122 is fixed to the base grinding ring 121, for example, by welding, and has a height higher than the base grinding ring in order to maintain the material bed height required for the grinding process. The iron-rich mineral release ring 123 is fixed on the bed holding ring 122, for example, by welding, and a plurality of discharge channels 124 for discharging iron-rich minerals are formed. For example, two exhaust channels 124 are exemplarily shown in FIG. 3A. However, those skilled in the art can understand that the number of discharge channels is not limited to this, and any appropriate number can be selected according to actual needs. Each of the plurality of discharge channels 124 has a top opening 1241 connected to the inner cavity of the roller mill and a bottom opening 1242 connected to the bed holding ring 122. According to an alternative embodiment, the top opening 1241 may have a width in the range of 3-8 mm, and the bottom opening 1242 may have a width in the range of 8-15 mm.

Further, according to an example, each of the plurality of discharge channels 124 may have a right-angled trapezoid shape, the lower bottom side of which is longer than the upper bottom side, as shown in FIG. 3A. Optionally, the angle γ formed by the oblique waist of the right-angled trapezoid shape and the bottom edge may be in the range of 85-92°. In addition, the distance L between the centers of the top openings of two adjacent discharge channels 124 may be in the range of 350-420 mm. For example, the bed holding ring 122 may be made of a conventional carbon steel material. In consideration of the abrasiveness of steel tailings, the iron-rich mineral release ring 123 may be made of, for example, a wear-resistant steel plate having a hardness that satisfies HRC58.

According to another embodiment of the present invention, the pneumatic separator 13 may further include a plurality of sorting swirl blades 131, a plurality of flow field intensity distribution plates 132 and a return plate 133, as shown in FIGS. 2 and 3B-3C Shown. Specifically, one end of each of the plurality of sorting swirl blades 131 is fixed to the shell 14 of the roller mill, for example, by welding, and is arranged to be spaced apart from each other. In addition, each sorting swirl blade 131 is inclined with respect to the horizontal direction. Preferably, the angle α formed by the sorting swirl blade 131 with the horizontal direction (as shown in FIG. 3C) may be in the range of 50-70°. Each of the plurality of flow field intensity distribution plates 132 is arranged along the vertical direction at intervals, and one end of each flow field intensity distribution plate 132 is connected to the plurality of sorting swirl blades 131 (for example, connected by welding) , The other end swings freely, thereby dividing the material discharge area into a strong wind area V ₁ , a medium wind field intensity area V ₂ and a weak wind area V ₃ . The return flow plate 133 is arranged above the plurality of sorting swirl blades 131 and the plurality of flow field intensity distribution plates 132, and one end of the return flow plate is fixed to the housing 14, for example, by welding. Referring to FIG. 2, the return plate 133 is an arc-shaped plate extending upward at an angle with respect to the horizontal direction. For example, the angle β formed by the return plate 133 with respect to the horizontal direction may be in the range of 45-65°. Optionally, the sorting swirl blade 131, the flow field intensity distribution plate 132, and the return plate 133 can all be made of a metal wear-resistant steel plate with a certain hardness, and the material hardness meets HRC 58 and above.

According to the other embodiment, a plurality of sorting swirling blades 131 combs the disordered flow entering the roller mill into an annular swirling flow. The multiple flow field intensity distribution plates 132 redistribute the air volume entering the wind-driven separator to adjust the outlet wind speed, thereby forming a flow field with _{outlet wind speed V 1} >V ₂ >V _3. For example, V ₁ may be 53-65 m/s, V ₂ may be 42-53 m/s, and V ₃ may be 30-42 m/s. Under the combined action of the two materials entering the pneumatic separator, the particles M3 with larger mass due to centrifugal force will move away from the grinding disc and fall into the weak wind area V ₃ , and the lift is insufficient to exit the roller mill; the particles with smaller mass M1 close to the grinding disc and merge Stay in the strong wind area V ₁ , go up to enter the three-stage quality sorter 4. The return plate 133 will be above the medium wind field strength V ₂ , and the medium particles M2 of quality with insufficient rising power are pushed back to the roller mill for re-grinding and dissociation.

According to a preferred embodiment of the present invention, the three-stage mass sorting machine may further include a power sorting rotor 401, guide blades 402 and strong swirling blades 403 which are arranged in sequence from the inside to the outside with the same center. The guide vane 402 and the strong swirling vane 403 are both fixed on the upper part of the shell of the roller mill, and the guide vane 402 is located inside the strong swirling vane 403. The power sorting rotor 401 is installed on the inner side of the guide vane 402, and may be connected with an electric motor and a reducer, for example, to provide rotary power for the power sorting rotor. According to an example, the power separation rotor 401, the guide blades 402, and the strong swirling blades 403 may all be made of a certain hardness of metal wear-resistant steel plates, and their material hardness meets HRC58 and above. The other light materials M1 selected by the pneumatic separator are sent to the three-stage mass separator 4. By adjusting the speed of the power separator rotor 401, the angle of the guide blade 402, and the angle of the strong swirling blade 403, it can be At the same time, the strong swirling blade 403 separates the heavy particles M1 _-1 _{of 1-2.5 mm, the light particles M1 -2} of 0.2-1.2 mm are separated by the guide blade 402, and the steel slag is separated by the power separation rotor 401. Micropowder M1 _-3 (for example, the quality is better than the first grade steel slag powder of GB/T20491).

Although the exemplary embodiments of the present invention have been described, it is obvious to those skilled in the art that changes can be made to these embodiments without departing from the spirit and principle of the present invention. The protection scope of the present invention is defined in the claims. And its equivalent form.

Claims

A dry-process steel tailings treatment system, including:

A roller mill, the roller mill includes a grinding disc for receiving and grinding steel tailings, an iron-rich mineral sorting device located on the grinding disc, and separate separation from the grinding disc and the iron-rich mineral A pneumatic separator connected to the device, the iron-rich mineral separation device is used to discharge iron-rich minerals in the grinded particles of the grinding disc from the grinding disc, and the pneumatic separator is used to receive the The discharged materials from the grinding disc are separated from the iron-rich minerals and other light materials through a wind field with varying strength and discharged from the roller mill;

A gravity separator, which is connected to the roller mill and receives the iron-rich minerals discharged from the roller mill to separate the iron-rich heavy particles, and the remaining mineral particles Return to the roller mill for repeated grinding, dissociation and sorting;

The first magnetic separator, the first magnetic separator is connected to the gravity separator to separate iron particles from the iron-rich heavy particles through magnetic separation, and return the remaining mineral particles to the Roll mill for repeated grinding, dissociation and sorting;

A three-stage mass sorting machine, the three-stage mass sorting machine is arranged on the upper part of the roller mill to receive other light materials discharged by the roller mill, and to sort out the other light materials according to the weight Heavy particles, light particles and steel slag powder;

A second magnetic separator, which is connected to the three-stage mass separator and receives the heavy particles for separating magnetic-rich iron oxide from the heavy particles by magnetic separation Iron fine powder, and return the remaining mineral particles to the roller mill for repeated grinding, dissociation and sorting; and

A third magnetic separator, which is connected to the three-stage mass separator and receives the light particles for separating iron-rich RO phase minerals from the light particles by magnetic separation , And return the remaining mineral particles to the roller mill for repeated grinding, dissociation and sorting.
The dry-process steel tailings treatment system according to claim 1, wherein the iron-rich mineral sorting device further comprises:

A base grinding ring, the base grinding ring is arranged on the grinding disc to carry grinding force;

A bed holding ring, the bed holding ring is fixed to the base grinding ring and has a height higher than the base grinding ring, and the bed holding ring is connected to the grinding disc; and

An iron-rich mineral release ring, the iron-rich mineral release ring is fixed on the bed holding ring and is formed with a plurality of discharge channels for discharging iron-rich minerals, each of the plurality of discharge channels Both have a top opening connected to the inner cavity of the roller mill and a bottom opening connected to the bed holding ring.
The dry-process steel tailings treatment system according to claim 2, wherein each of the plurality of discharge channels has a right-angled trapezoid shape, and a lower base of the right-angled trapezoidal shape is longer than an upper base.
The dry-process steel tailings treatment system according to claim 3, wherein the angle formed by the oblique waist of the right-angled trapezoid shape and the bottom edge is in the range of 85-92°.
The dry-process steel tailings treatment system according to claim 2, wherein the top opening has a width in the range of 3-8 mm, and the bottom opening has a width in the range of 8-15 mm.
The dry-process steel tailings treatment system according to claim 2, wherein the distance between the centers of the top openings of two adjacent discharge channels is in the range of 350-420 mm.
The dry-process steel tailings treatment system according to claim 2, wherein the surface of the base grinding ring in contact with the material adopts metal wear-resistant surfacing treatment.
The dry-process steel tailings treatment system according to claim 2, wherein the material bed holding ring is fixed to the grinding disc by a bolt connection.
The dry-process steel tailings treatment system according to claim 1, wherein the pneumatic separator further comprises:

A plurality of sorting swirl blades, one end of each of the plurality of sorting swirl blades is fixed to the shell of the roller mill and is spaced apart from each other, and each of the sorting swirl blades Tilt relative to the horizontal;

A plurality of flow field intensity distribution plates, each of the plurality of flow field intensity distribution plates is arranged along a vertical direction at intervals, and one end of each of the flow field intensity distribution plates is connected to the plurality of sub-distribution plates Select the swirling blades and swing the other end freely, thereby dividing the material discharge area into a strong wind area, a medium wind field intensity area and a weak wind area; and

The return plate is arranged above the plurality of sorting swirl blades and the plurality of flow field intensity distribution plates, and one end is fixed to the shell, and the return plate is opposite to An arc-shaped plate that extends upward at an angle in the horizontal direction.
The dry-process steel tailings treatment system according to claim 9, wherein the angle formed by the sorting swirl blade and the horizontal direction is in the range of 50-70°.
The dry-process steel tailings treatment system according to claim 9, wherein the angle formed by the return plate with respect to the horizontal direction is in the range of 45-65°.
The dry-process steel tailings treatment system according to claim 1, wherein the three-stage mass sorting machine further comprises a power sorting rotor, guide blades and strong swirling blades arranged in order from the inside to the outside with the same circle center, wherein :

The strong swirling blade and the guide blade are fixed on the upper part of the shell of the roller mill; and

The strong swirling blade is used for sorting out heavy particles, the guide blade is used for sorting out light particles, and the dynamic sorting rotor is used for sorting out the steel slag powder.
The dry-process steel tailings treatment system according to claim 12, wherein the power separation rotor is connected with an electric motor and a reducer to provide rotary power for the power separation rotor.