A dry grinding and dry separation apparatus and method for a ferromagnetic ore or reduced product

Abstract

The application provides a strong magnetic ore or reduced product dry grinding and dry separation device and method, and belongs to the technical field of mineral processing. The device comprises horizontal cylinder bodies with different diameters at two ends, transmission devices and supporting devices outside the cylinder bodies, a concentrate discharge port opened on the small-diameter side of the cylinder body, an alternating magnetic system below the transport belt of the concentrate discharge port and below the grinding and separating cylinder body, inlayed lining plates on the inner wall of the grinding and separating cylinder body, rod-shaped grinding media with different diameters at two ends in the grinding and separating cylinder body, a feed chute inside the small-diameter side of the cylinder body, and a sieve plate inside the large-diameter side of the cylinder body. The grinding and separating cylinder body, the lining plates, the rod-shaped grinding media and the sieve plate are all non-magnetic materials. The material enters the inside of the cylinder body through the feed chute, is dry ground and is also subjected to grinding and separation under the action of the magnetic field. The device realizes the dry grinding and dry separation of the fine-grained strong magnetic ore or reduced product at the same time, and can discharge the concentrate in time, and solves the problems of low concentrate grade or recovery rate caused by the non-disintegration of monomers, over-grinding, magnetic agglomeration and the like in the grinding and magnetic separation process.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, and in particular to a dry grinding and dry separation device and method for strongly magnetic ores or reduction products. Background Technology

[0002] Strongly magnetic ores refer to magnetite, titanomagnetite, pyrrhotite, and semi-pseudomorphic hematite, etc. The grinding and magnetic separation process for these ores typically requires water as the separation medium. Currently, grinding and magnetic separation technology has two significant drawbacks: first, in water-scarce and arid regions, many mineral resources cannot be developed and utilized due to water scarcity; second, although concentration and dehydration can achieve water resource recycling, tailings treatment costs are high, and the process also involves numerous equipment requirements, large investments, and high production costs.

[0003] Strongly magnetic reduction products refer to reduction products containing strongly magnetic substances such as metallic iron, ferrotitanium alloys, and ferronickel alloys. These reduction products are primarily separated through wet grinding and magnetic separation. In addition to the aforementioned problems during production, the grinding process also presents the following issues: Compared to strongly magnetic ores, the strongly magnetic substances in these reduction products exhibit metallic ductility. Therefore, it is crucial to promptly remove the liberated concentrate during grinding. Otherwise, over-grinding can cause the ductile magnetic substances to encapsulate the gangue, reducing the concentrate grade and affecting its quality. Furthermore, since the concentrate comes into contact with water and air during wet grinding and magnetic separation, if it is not filtered and dried promptly after grinding and magnetic separation, it is highly susceptible to oxidation, which also negatively impacts concentrate quality.

[0004] Currently, dry grinding, dry separation, and magnetic separation processes are mainly used for coarse grinding and rough separation. The purpose is to pre-select and discard waste, reducing the amount of ore fed into the mill for subsequent production, increasing the grade of the raw ore being processed, and thus reducing energy consumption. There are two main reasons why dry grinding and dry separation cannot be used for fine separation: Firstly, dry grinding cannot achieve the complete liberation of valuable minerals from gangue minerals. Currently, the lower limit of particle size for dry grinding is -3mm (the discharge particle size of high-pressure roller mills), while the liberation particle size of strongly magnetic ores or reduction products is generally below 0.15mm. Secondly, dry magnetic separation easily causes non-magnetic minerals to be mixed with magnetic minerals, resulting in insufficient mineral separation and making it difficult to improve the grade or achieve a low recovery rate.

[0005] Despite the aforementioned shortcomings of dry grinding and dry separation, it has unparalleled advantages over wet grinding and magnetic separation. For example, magnetic separation does not require dewatering, thus avoiding groundwater pollution; it saves on supporting equipment and reduces tailings disposal costs; it can reduce beneficiation costs in arid and water-scarce areas; and for strongly magnetic reduction products, it prevents metallic iron, ferro-titanium alloys, and ferronickel alloys in the concentrate from coming into contact with water, thus preventing the concentrate from being oxidized during filtration and drying. Summary of the Invention

[0006] This invention addresses the problems of existing dry grinding and separation methods, which are limited to coarse grinding and separation, and the inability to promptly remove strongly magnetic reduction products during the grinding process, resulting in low concentrate grades or low recovery rates. It provides a dry grinding and separation device and method for strongly magnetic ores or reduction products. This invention performs dry separation operations simultaneously with dry grinding of strongly magnetic ores or reduction products at a particle size of -3mm, and can promptly remove liberated concentrate. It solves the problems of low concentrate grades or low recovery rates caused by unliberated monomers, over-grinding, and magnetic agglomeration during grinding and magnetic separation of strongly magnetic ores or reduction products, achieving dry grinding and separation of fine-grained strongly magnetic ores or reduction products, and reducing energy consumption during the grinding and magnetic separation process.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A dry grinding and dry separation device for strongly magnetic ores or reduction products includes a grinding cylinder, idlers, a feed chute, a sleeve, a concentrate conveyor belt, a concentrate alternating strong magnetic system, a grinding and separation alternating magnetic system, a drive gear, a driven gear, a support base, a tailings conveyor belt, and rod-shaped grinding media.

[0009] The grinding cylinder is a horizontal cylindrical structure with different diameters at both ends. A concentrate discharge port is provided on the cylinder wall at the smaller diameter end of the cylinder, and a tailings discharge port is provided on the cylinder wall at the larger diameter end of the cylinder. A concentrate conveyor belt is provided below the concentrate discharge port, and a tailings conveyor belt is provided below the tailings discharge port.

[0010] The grinding cylinder is equipped with a sieve plate inside the large diameter end of the cylinder, and the space between the sieve plate and the concentrate discharge port is filled with rod-shaped grinding media.

[0011] Both the large-diameter end and the small-diameter end of the grinding cylinder are equipped with idler rollers. Sleeves are provided at both ends of the grinding cylinder to make horizontal contact with the idler rollers in order to counteract the horizontal component force. The idler rollers are mounted on the support base. The inner diameter of the sleeve is slightly larger than the outer diameter of the cylinder to ensure that the sleeve is in horizontal contact with the idler roller. The grinding cylinder is in inclined contact with the sleeve.

[0012] The outer side of the large-diameter end of the grinding cylinder is surrounded by a driven gear. The driven gear meshes with the driving gear to provide power to the grinding cylinder and ensure its rotation.

[0013] The grinding and screening cylinder is provided with a feeding chute at the small diameter end of the cylinder to ensure that the material is fed into the interior of the grinding and screening cylinder.

[0014] A high-intensity alternating magnetic field system for concentrate is installed below the concentrate discharge port, and an alternating magnetic field system for grinding and screening is installed below the grinding and screening cylinder. The alternating magnetic field system for grinding and screening is placed on a support base.

[0015] The ratio of the smaller diameter end diameter to the larger diameter end diameter at both ends of the grinding and screening cylinder is 1:3, and the ratio of the smaller diameter end diameter to the length of the cylinder centerline is 1:4 to 1:12.

[0016] The inner wall of the grinding cylinder is lined with a liner from the sieve plate to the small diameter end of the cylinder.

[0017] The alternating strong magnetic system for the concentrate is located inside the concentrate conveyor belt.

[0018] The rod-shaped grinding media moves in the grinding cylinder in a cascading or throwing manner; the length of the rod-shaped grinding media is greater than the distance between the two ends of the grinding and separation alternating magnetic system, but less than the distance between the screen plate and the concentrate discharge port; the rod-shaped grinding media is a rod with unequal diameters at both ends, and the ratio of the minimum diameter to the maximum diameter of the rod-shaped grinding media is 2:3.

[0019] The filling rate of the rod-shaped grinding media inside the grinding cylinder is 30-50%.

[0020] The rotational speed of the dry grinding and dry separation device is related to the diameter of the cylinder. The normal mill speed is about 76% of the critical speed.

[0021] The grinding cylinder, liner, rod-shaped grinding media, screen plate, and feed chute are all made of non-magnetic materials.

[0022] The grinding and sorting alternating magnetic system includes a strong magnetic alternating magnetic system, a medium magnetic alternating magnetic system, and a weak magnetic alternating magnetic system.

[0023] The grinding and beneficiation alternating magnetic system is located between the concentrate conveyor belt and the tailings conveyor belt, below the grinding and beneficiation cylinder, and is in a semi-enclosed shape;

[0024] The strong magnetic alternating magnetic system is close to the tailings conveyor belt, the weak magnetic alternating magnetic system is adjacent to the concentrate alternating strong magnetic system, and the medium magnetic alternating magnetic system is located between the strong magnetic alternating magnetic system and the weak magnetic alternating magnetic system. The distance between adjacent alternating magnetic systems is 0.1 to 1 m. The same alternating magnetic system has equal spacing but unequal magnetic field strength, equal magnetic field strength but unequal spacing, or equal magnetic field strength at equal spacing.

[0025] The strong magnetic alternating magnetic system, the medium magnetic alternating magnetic system, the weak magnetic alternating magnetic system, and the concentrate alternating strong magnetic system are all electromagnets, and the magnetic field strengths generated within the grinding cylinder range from 200 to 1600 kA / m, 160 to 480 kA / m, 72 to 200 kA / m, and 72 to 200 kA / m, respectively; the magnetic wrap angle of the strong magnetic alternating magnetic system, the medium magnetic alternating magnetic system, and the weak magnetic alternating magnetic system is 90 to 150°.

[0026] The alternating magnetic system for concentrate is located inside the concentrate conveyor belt and is parallel to the concentrate conveyor belt.

[0027] The application method of this dry grinding and dry separation device includes the following steps:

[0028] S1. The material is fed into the grinding cylinder through the feed chute and is located above the medium magnetic alternating magnetic system. The material undergoes dry grinding and dry separation in the grinding cylinder.

[0029] S2. Undissociated particles are adsorbed onto the liner under the action of a strong or medium magnetic alternating magnetic system, which enhances the impact and grinding of the particles. Furthermore, the rod-shaped grinding media inside the grinding cylinder above the strong magnetic alternating magnetic system has a coarse end, which makes the impact and grinding effect even stronger, further enhancing the dissociation of useful minerals from gangue minerals.

[0030] S3. As the proportion of gangue on the material particles gradually decreases, the material moves along the sorting cylinder toward the concentrate discharge port under the action of the alternating magnetic system. Finally, the concentrate that has been liberated falls onto the concentrate conveyor belt under the action of the alternating strong magnetic system.

[0031] S4. As the proportion of concentrate in the material particles gradually decreases, the material moves along the separation cylinder towards the tailings discharge port under the action of gravity and horizontal force, and finally falls onto the tailings conveyor belt under the action of gravity.

[0032] The material is a strongly magnetic ore or a reduction product. The strongly magnetic ore includes magnetite, titanomagnetite, pyrrhotite, and semi-pseudomorphic hematite. The strongly magnetic reduction product includes strongly magnetic substances containing metallic iron, titanium-iron alloy, or nickel-iron alloy.

[0033] The above technical solution has at least the following advantages compared with the existing technology:

[0034] In the above scheme, dry grinding and dry magnetic separation are carried out simultaneously. Undissociated particles will be adsorbed onto the liner under the action of a strong or medium alternating magnetic system, which enhances the impact and grinding of the particles. At the same time, when the proportion of magnetic minerals in the material particles is small, the material will be adsorbed within the range of the alternating strong magnetic system under the action of gravity and horizontal force. The rod-shaped grinding media above the alternating strong magnetic system is coarse, which further enhances the dissociation of useful minerals from gangue minerals. As the proportion of magnetic minerals in the material particles gradually increases, the material gradually moves towards the concentrate discharge port under the action of the alternating magnetic system. It then moves through the alternating medium magnetic system to the magnetic field of the alternating weak magnetic system. At the same time, the rotation of the cylinder increases the tumbling of the material, which enhances the magnetic separation effect until the useful minerals and gangue in the material are completely dissociated and discharged from the cylinder. This process can promptly remove completely dissociated useful mineral particles, avoiding over-grinding of these particles. In particular, it can effectively prevent the formation of gangue by ductile and strongly magnetic substances due to over-grinding, thereby improving concentrate grade or recovery rate and reducing energy consumption. At the same time, it can also prevent the concentrate from coming into contact with water and air simultaneously, preventing the concentrate from being oxidized and improving concentrate quality. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of a dry grinding and dry separation device for strongly magnetic ores or reduction products according to the present invention.

[0037] Figure 2 This is a partial cross-sectional structural schematic diagram of the dry grinding and dry separation device for strongly magnetic ores or reduction products of the present invention.

[0038] Figure 3 This is a partial cross-sectional view of the structure of the device of the present invention during operation;

[0039] Figure 4 This is a schematic diagram of the rod-shaped grinding media structure of the present invention.

[0040] The annotations in the attached figures are explained as follows:

[0041] 1-Idler roller; 2-Feed chute; 3-Sleeve; 4-Concentrate discharge port; 5-Concentrate conveyor belt; 6-Concentrate alternating strong magnetic system; 7-Grinding cylinder; 8-Liner; 9-Grinding alternating magnetic system; 10-Driving gear; 11-Driven gear; 12-Support base; 13-Screen plate; 14-Tailyard discharge port; 15-Tailyard conveyor belt; 16-Rod-shaped grinding media;

[0042] 9-1: Strong magnetic alternating magnetic system one; 9-2: Strong magnetic alternating magnetic system two; 9-3: Strong magnetic alternating magnetic system three; 9-4: Strong magnetic alternating magnetic system four; 9-5: Medium magnetic alternating magnetic system one; 9-6: Medium magnetic alternating magnetic system two; 9-7: Medium magnetic alternating magnetic system three; 9-8: Medium magnetic alternating magnetic system four; 9-9: Weak magnetic alternating magnetic system one; 9-10: Weak magnetic alternating magnetic system two; 9-11: Weak magnetic alternating magnetic system three; 9-12: Weak magnetic alternating magnetic system four. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0044] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0045] It should be noted that the terms "up", "down", "left", "right", "front", and "back" used in this invention are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0046] This invention provides a dry grinding and dry separation device and method for strongly magnetic ores or reduction products.

[0047] like Figure 1 , Figure 2 and Figure 3 As shown, the device includes a grinding cylinder 7, idler rollers 1, feed chute 2, sleeve 3, concentrate conveyor belt 5, concentrate alternating strong magnetic system 6, grinding alternating magnetic system 9, drive gear 10, driven gear 11, support base 12, tailings conveyor belt 15, and rod-shaped grinding media 16.

[0048] The grinding cylinder 7 is a horizontal cylindrical structure with different diameters at both ends. A concentrate discharge port 4 is provided on the cylinder wall at the smaller diameter end of the cylinder, and a tailings discharge port 14 is provided on the cylinder wall at the larger diameter end of the cylinder. A concentrate conveyor belt 5 is provided below the concentrate discharge port 4, and a tailings conveyor belt 15 is provided below the tailings discharge port 14.

[0049] The grinding cylinder 7 is equipped with a screen plate 13 inside the large diameter end of the cylinder, and the space between the screen plate 13 and the concentrate discharge port 4 is filled with rod-shaped grinding media 16.

[0050] The grinding cylinder 7 has rollers 1 installed at the lower part of both the large-diameter end and the small-diameter end. Sleeves 3 are installed at both ends of the grinding cylinder 7 to make horizontal contact with the rollers 1 in order to counteract the horizontal component force. The rollers 1 are installed on the support base 12. The inner diameter of the sleeve is slightly larger than the outer diameter of the cylinder to ensure that the sleeve and the roller are in horizontal contact. The grinding cylinder and the sleeve are in inclined contact.

[0051] The outer side of the large-diameter end of the grinding cylinder 7 is surrounded by a driven gear 11, which meshes with the driving gear (motor) 10 to provide power to the grinding cylinder 7.

[0052] The grinding and screening cylinder 7 is provided with a feeding chute 2 at the small diameter end of the cylinder to ensure that the material is fed into the interior of the grinding and screening cylinder.

[0053] A concentrate alternating strong magnetic system 6 is provided below the concentrate discharge port 4, and a grinding and separation alternating magnetic system 9 is provided below the grinding and separation cylinder 7. The grinding and separation alternating magnetic system 9 is placed on the support base 12.

[0054] The inner wall of the grinding cylinder 7 is lined with a liner 8 from the screen plate 13 to the small diameter end of the cylinder. The ratio of the diameter of the small diameter end to the diameter of the large diameter end at both ends of the grinding cylinder is 1:3, and the ratio of the diameter of the small diameter end to the length of the center line of the cylinder is 1:4 to 1:12.

[0055] The alternating strong magnetic system 6 for concentrate is located inside the concentrate conveyor belt 5.

[0056] The rod-shaped grinding media 16 moves within the grinding cylinder 7 in a cascading or throwing manner.

[0057] like Figure 4 As shown, the rod-shaped grinding media 16 is a rod-shaped material with one end thicker than the other. The length of the rod-shaped grinding media is greater than the distance between the two ends of the grinding and beneficiation alternating magnetic system, but less than the distance between the screen plate and the concentrate discharge port. The ratio of the small diameter to the large diameter of the rod-shaped grinding media is 2:3.

[0058] The grinding cylinder 7, liner 8, rod-shaped grinding media 16, sieve plate 13, and feed chute 2 are all made of non-magnetic materials.

[0059] The grinding and beneficiation alternating magnetic system 9 includes a strong magnetic alternating magnetic system, a medium magnetic alternating magnetic system, and a weak magnetic alternating magnetic system. The strong magnetic alternating magnetic system is close to the tailings conveyor belt, the weak magnetic alternating magnetic system is adjacent to the concentrate alternating strong magnetic system, and the medium magnetic alternating magnetic system is located between the strong magnetic alternating magnetic system and the weak magnetic alternating magnetic system.

[0060] The strong magnetic alternating magnetic system, the medium magnetic alternating magnetic system, the weak magnetic alternating magnetic system, and the concentrate alternating strong magnetic system are all electromagnets, and the magnetic field strength generated within the grinding cylinder ranges from 200 to 1600 kA / m, 160 to 480 kA / m, 72 to 200 kA / m, and 72 to 200 kA / m, respectively. The magnetic wrap angle of the strong magnetic alternating magnetic system, the medium magnetic alternating magnetic system, and the weak magnetic alternating magnetic system is 90 to 150°, and the distance between adjacent alternating magnetic systems is 0.1 to 1 m.

[0061] In the actual design, the magnetic field strengths of the strong alternating magnetic system, the medium alternating magnetic system, the weak alternating magnetic system, and the concentrate alternating magnetic system are 600 kA / m, 300 kA / m, 160 kA / m, and 200 kA / m, respectively. The magnetic system wrap angle of the strong alternating magnetic system, the medium alternating magnetic system, and the weak alternating magnetic system is 120°, and the distance between adjacent alternating magnetic systems is 0.2 m. Figure 2 The strong magnetic alternating magnetic system is divided into strong magnetic alternating magnetic system 1 (9-1), strong magnetic alternating magnetic system 2 (9-2), strong magnetic alternating magnetic system 3 (9-3), and strong magnetic alternating magnetic system 4 (9-4). The medium magnetic alternating magnetic system is divided into medium magnetic alternating magnetic system 1 (9-5), medium magnetic alternating magnetic system 2 (9-6), medium magnetic alternating magnetic system 3 (9-7), and medium magnetic alternating magnetic system 4 (9-8). The weak magnetic alternating magnetic system is divided into weak magnetic alternating magnetic system 1 (9-9), weak magnetic alternating magnetic system 2 (9-10), weak magnetic alternating magnetic system 3 (9-11), and weak magnetic alternating magnetic system 4 (9-12).

[0062] In practical applications, the dry grinding and dry separation process includes the following steps:

[0063] S1. The material is fed into the grinding cylinder through the feed chute and is located above the medium magnetic alternating magnetic system. The material undergoes dry grinding and dry separation in the grinding cylinder.

[0064] S2. Undissociated particles are adsorbed onto the liner under the action of a strong or medium magnetic alternating magnetic system, which enhances the impact and grinding of the particles. Furthermore, the rod-shaped grinding media inside the grinding cylinder above the strong magnetic alternating magnetic system has a coarse end, which makes the impact and grinding effect even stronger, further enhancing the dissociation of useful minerals from gangue minerals.

[0065] S3. As the proportion of gangue on the material particles gradually decreases, the material moves along the sorting cylinder toward the concentrate discharge port under the action of the alternating magnetic system. Finally, the concentrate that has been liberated falls onto the concentrate conveyor belt under the action of the alternating strong magnetic system.

[0066] S4. As the proportion of concentrate in the material particles gradually decreases, the material moves along the separation cylinder towards the tailings discharge port under the action of gravity and horizontal force, and finally falls onto the tailings conveyor belt under the action of gravity.

[0067] The device of the present invention is suitable for processing strongly magnetic ores or reduction products. The strongly magnetic ores include magnetite, titanomagnetite, pyrrhotite, and semi-pseudomorphic hematite. The strongly magnetic reduction products include strongly magnetic substances containing metallic iron, ferrotitanium alloy, or ferronickel alloy.

[0068] Table 1 shows the magnetic field strength generated by the alternating magnetic system inside the grinding cylinder and the pattern of magnetic field generation when energized. * indicates that a magnetic field is generated when energized, and a blank space indicates that there is no magnetic field.

[0069] Under the influence of gravity and horizontal forces, the gangue moves along the sorting cylinder toward the tailings discharge port and eventually falls onto the tailings conveyor belt.

[0070] Table 1

[0071]

[0072] The following points need to be explained:

[0073] (1) The accompanying drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention. Other structures can refer to the general design.

[0074] (2) Where there is no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0075] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A dry grinding and dry separation device for strongly magnetic ores or reduction products, characterized in that, It includes grinding cylinder, idler rollers, feed chute, sleeve, concentrate conveyor belt, concentrate alternating strong magnetic system, grinding alternating magnetic system, drive gear, driven gear, support base, tailings conveyor belt and rod grinding media; The grinding cylinder is a horizontal cylindrical structure with different diameters at both ends. A concentrate discharge port is provided on the cylinder wall at the smaller diameter end of the cylinder, and a tailings discharge port is provided on the cylinder wall at the larger diameter end of the cylinder. A concentrate conveyor belt is provided below the concentrate discharge port, and a tailings conveyor belt is provided below the tailings discharge port. The grinding cylinder is equipped with a sieve plate inside the large diameter end of the cylinder, and the space between the sieve plate and the concentrate discharge port is filled with rod-shaped grinding media. The grinding cylinder is equipped with support rollers at the lower part of both the large-diameter end and the small-diameter end. Sleeves are provided at both ends of the grinding cylinder to make horizontal contact with the support rollers in order to counteract the horizontal component force. The support rollers are mounted on the support base. The outer side of the large-diameter end of the grinding cylinder is surrounded by a driven gear, which meshes with the driving gear to provide power to the grinding cylinder; The grinding and screening cylinder is provided with a feeding chute at the small diameter end of the cylinder to ensure that the material is fed into the interior of the grinding and screening cylinder. A high-intensity alternating magnetic field system for concentrate is installed below the concentrate discharge port, and an alternating magnetic field system for grinding and screening is installed below the grinding and screening cylinder. The alternating magnetic field system for grinding and screening is placed on a support base. The grinding and beneficiation alternating magnetic system includes a strong magnetic alternating magnetic system, a medium magnetic alternating magnetic system, and a weak magnetic alternating magnetic system. The grinding and beneficiation alternating magnetic system is located between the concentrate conveyor belt and the tailings conveyor belt, below the grinding and beneficiation cylinder, and presents a semi-enclosed shape. The strong magnetic alternating magnetic system is close to the tailings conveyor belt, the weak magnetic alternating magnetic system is adjacent to the concentrate alternating strong magnetic system, and the medium magnetic alternating magnetic system is located between the strong magnetic alternating magnetic system and the weak magnetic alternating magnetic system. The distance between adjacent alternating magnetic systems is 0.1~1m. The same alternating magnetic system has equal spacing but unequal magnetic field strength, or equal magnetic field strength but unequal spacing, or equal magnetic field strength but equal spacing.

2. The dry grinding and dry separation device for strongly magnetic ores or reduction products according to claim 1, characterized in that, The ratio of the smaller diameter end diameter to the larger diameter end diameter at both ends of the grinding and screening cylinder is 1:3, and the ratio of the smaller diameter end diameter to the length of the cylinder centerline is 1:4 to 1:

12. The inner wall of the grinding cylinder is lined with a liner from the sieve plate to the small diameter end of the cylinder.

3. The dry grinding and dry separation device for strongly magnetic ores or reduction products according to claim 1, characterized in that, The alternating strong magnetic system for the concentrate is located inside the concentrate conveyor belt.

4. The dry grinding and dry separation device for strongly magnetic ores or reduction products according to claim 1, characterized in that, The rod-shaped grinding media moves in the grinding cylinder in a cascading or throwing manner; the length of the rod-shaped grinding media is greater than the distance between the two ends of the grinding and separation alternating magnetic system, and less than the distance between the screen plate and the concentrate discharge port; the rod-shaped grinding media is a rod with unequal diameters at both ends, and the ratio of the minimum diameter to the maximum diameter of the rod-shaped grinding media is 2:

3. The filling rate of the rod-shaped grinding media inside the grinding cylinder is 30-50%.

5. The dry grinding and dry separation device for strongly magnetic ores or reduction products according to claim 1, characterized in that, The grinding cylinder, liner, rod-shaped grinding media, screen plate, and feed chute are all made of non-magnetic materials.

6. The dry grinding and dry separation device for strongly magnetic ores or reduction products according to claim 1, characterized in that, The strong magnetic alternating magnetic system, the medium magnetic alternating magnetic system, the weak magnetic alternating magnetic system, and the concentrate alternating strong magnetic system are all electromagnets, generating magnetic field strengths within the grinding cylinder ranging from 200 to 1600 kA / m, 160 to 480 kA / m, 72 to 200 kA / m, and 72 to 200 kA / m, respectively; the magnetic wrap angle of the strong magnetic alternating magnetic system, the medium magnetic alternating magnetic system, and the weak magnetic alternating magnetic system is 90 to 150°. The alternating magnetic system for concentrate is located inside the concentrate conveyor belt and is parallel to the concentrate conveyor belt.

7. The application method of the dry grinding and dry separation device for strongly magnetic ores or reduction products according to claim 1, characterized in that, The steps include the following: S1. The material is fed into the grinding cylinder through the feed chute and is located above the medium magnetic alternating magnetic system. The material undergoes dry grinding and dry separation in the grinding cylinder. S2. Undissociated particles are adsorbed onto the liner under the action of a strong or medium magnetic alternating magnetic system, which enhances the impact and grinding of the particles. Furthermore, the rod-shaped grinding media inside the grinding cylinder above the strong magnetic alternating magnetic system has a coarse end, which makes the impact and grinding effect even stronger, further enhancing the dissociation of useful minerals from gangue minerals. S3. As the proportion of gangue on the material particles gradually decreases, the material moves along the sorting cylinder toward the concentrate discharge port under the action of the alternating magnetic system. Finally, the concentrate that has been liberated falls onto the concentrate conveyor belt under the action of the alternating strong magnetic system. S4. As the proportion of concentrate in the material particles gradually decreases, the material moves along the separation cylinder towards the tailings discharge port under the action of gravity and horizontal force, and finally falls onto the tailings conveyor belt under the action of gravity.

8. The application method of the dry grinding and dry separation device for strongly magnetic ores or reduction products according to claim 7, characterized in that, The material is a strongly magnetic ore or a reduction product. The strongly magnetic ore includes magnetite, titanomagnetite, pyrrhotite, and semi-pseudomorphic hematite. The strongly magnetic reduction product includes strongly magnetic substances containing metallic iron, titanium-iron alloy, or nickel-iron alloy.

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