Multi-roller permanent magnet dry magnetic separator and magnetic separation process thereof

Abstract

The invention relates to the technical field of mineral separation engineering, in particular to a multi-roller permanent magnet dry type magnetic separator and a magnetic separation process thereof.A plurality of magnetic separation rollers are connected into a sealed box, each magnetic separation roller comprises a roller shaft, a hub, an inner cylinder, an outer cylinder, a scraping strip and a magnetic system, the magnetic system is fixedly connected to the outer wall of the inner cylinder, the outer cylinder is fixedly connected to the roller shaft, and the roller shaft is fixedly connected to the hub; the outer barrel is rotationally connected to the outer side of the magnetic system, the scraping strip is fixedly connected to the outer wall of the outer barrel, the magnetic system is partially arranged on the outer wall of the inner barrel in the circumferential direction, the area with the magnetic system forms a magnetic separation area, the area without the magnetic system forms an unloading area, and the unloading area of each magnetic separation roller is close to the magnetic separation area of the other adjacent magnetic separation roller. Due to the arrangement of the multiple magnetic separation rollers, the multiple magnetic separation rollers are continuously separated by the multiple magnetic systems, after magnetic materials are subjected to magnetic separation through the multiple magnetic systems, iron ore concentrate with the high grade is obtained, the effects of improving the iron ore concentrate grade and improving the separation efficiency are achieved, and the problem that the metal recovery rate is low is solved.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing engineering, in particular to a multi-roller permanent magnetic dry magnetic separator and a magnetic separation process thereof. Background Art

[0002] At present, electromagnetic separators are the mainstream equipment for high-intensity magnetic separation. Since the electromagnets of high-intensity magnetic separation equipment require excitation power supply and cooling system, the equipment is not only complex in structure, inconvenient to maintain, expensive, but also has high operating costs. Permanent magnet separators can provide a stable magnetic field after only one magnetization, and do not require excitation power consumption and cooling system during production. Compared with the same type of electromagnetic high-gradient magnetic separators, permanent magnet separators have simple and compact equipment structure, light weight, small footprint, low equipment cost and operating cost. With the advent of high-performance rare earth permanent magnet materials and the improvement of their magnetic properties, the permanent magnetization of electromagnetic high-intensity magnetic separators has attracted increasing attention from the industry.

[0003] At present, although permanent magnet magnetic separators have preliminarily solved the problems of magnetic system structure, magnetic field strength, blockage during sorting, and have the conditions for initial application in industrial production, in actual application, permanent magnet magnetic separators are mainly used in wet magnetic separation of magnetic materials and are less used in dry magnetic separation.

[0004] Dry magnetic separator is a magnetic separation equipment for separating dry magnetic minerals. Compared with wet magnetic separator, which needs to use liquid as diluent to improve separation efficiency, dry magnetic separator requires that the minerals to be separated are dry and the particles can move freely and be independent and free.

[0005] Dry magnetic separators mainly include magnetic pulley dry separators, magnetic reversing drum dry separators and horizontal wind-magnetic separators. The magnetic system wrap angle of the magnetic pulley dry separator is generally 180°, the inner drum with the magnetic system does not rotate, and the electric drum outside the magnetic system rotates; the magnetic reversing drum dry separator uses a rotating magnetic system with a magnetic system wrap angle of 360°. The inner drum with the magnetic system and the electric drum outside the magnetic system are driven separately, which increases the frequency of magnetic reversal of the material, thereby improving the reversal effect of the material. The magnetic pulley dry separator is sorted in the air and is mainly used to sort large, coarse-grained strong magnetic ores. Compared with the wet magnetic separator, which needs to use water as a diluent to improve the sorting efficiency when sorting minerals, the dry magnetic separator requires the sorted minerals to be dry and the particles can move freely. Magnetic pulley dry separator and magnetic reversal drum dry separator are mainly suitable for materials with a particle size of -80mm after medium or fine crushing, such as magnetite, blast furnace slag, steel slag, etc. The strong magnetic field and weak magnetic field areas of the magnetic system act alternately on each other, so that the ore particles are magnetically reversed and magnetically stirred, so that the magnetic clusters and magnetic chains adsorbed on the outer cylinder are destroyed, and some ore particles and conjoined bodies with weaker magnetism can be effectively separated, thereby reducing the inclusion of non-magnetic materials in the magnetic particles. The horizontal wind-magnetic separation machine is mainly suitable for dry magnetic separation of magnetic materials with a particle size of -200 mesh. This equipment aims at the problems of long production process, low concentrate grade and low recovery rate in the traditional dry magnetic separation process. By setting multiple groups of magnetic systems in the horizontal wind-magnetic separation device, after the magnetic materials enter the magnetic separation space, magnetic agglomeration is generated under the action of magnetic induction intensity. When the magnetic agglomerated materials enter the "low field strength" area of ​​the magnetic system, the "magnetic agglomeration" is broken by the disturbance of the blowing air flow, and the non-magnetic materials are blown out from the material layer, so that the materials to be separated repeatedly experience the process of "agglomeration"-"dispersing agglomeration"-"eliminating non-magnetic particles"-"re-agglomeration"-"re-dispersing"-"re-eliminating", thereby improving the separation accuracy and separation efficiency. The main problems of this device are: low separation efficiency of magnetic materials, low grade of iron concentrate produced, and low metal recovery rate in the magnetic separation process. Summary of the invention

[0006] The object of the present invention is to provide a multi-roller permanent magnetic dry magnetic separator and a magnetic separation process thereof, so as to solve the problem existing in the dry magnetic separator when separating magnetic materials with a particle size of -200 mesh accounting for more than 80%.

[0007] In order to solve the above technical problems, the present invention provides a multi-roller permanent magnetic dry magnetic separator, which includes a sealed box body, a hopper is connected to the top of the sealed box body, a plurality of magnetic separation rollers are connected inside the sealed box body, the plurality of magnetic separation rollers are linearly evenly distributed in the horizontal direction, the plurality of magnetic separation rollers are linearly evenly distributed in the vertical direction, the plurality of magnetic separation rollers rotate clockwise, the hopper is arranged above the first magnetic separation roller of the plurality of magnetic separation rollers, a concentrate collecting pipe is arranged on the sealed box body, the concentrate collecting pipe is arranged on the side and lower part of the last magnetic separation roller among the plurality of magnetic separation rollers, the heights of the plurality of magnetic separation rollers in the vertical direction from the hopper to the concentrate collecting pipe are successively reduced, a concentrate discharge port is arranged below the concentrate collecting pipe, a concentrate sealed silo is arranged outside the sealed box body, the concentrate discharge port extends into the concentrate sealed silo, a tailings discharge port is arranged at the lower part of the sealed box body, and a tailings sealed silo is arranged outside the sealed box body. A sealed silo, a tailings discharge port extends out of the tailings sealed silo, each magnetic separation roller includes a roller shaft, a hub, an inner cylinder, an outer cylinder, a scraper bar and a magnetic system, the roller shaft is rotatably connected to the sealed box body, the inner cylinder is fixedly connected to the hub, the hub is fixedly connected to the sealed box body, the magnetic system is fixedly connected to the outer wall of the inner cylinder, the outer cylinder is fixedly connected to the roller shaft, the outer cylinder is rotatably connected to the outside of the magnetic system, the scraper bar is fixedly connected to the outer wall of the outer cylinder, a part of the magnetic system is set on the outer wall of the inner cylinder along the circumferential direction, the area where the magnetic system is set forms a magnetic separation area, and the area where the magnetic system is not set forms a discharge area, the discharge area of ​​each magnetic separation roller is close to the magnetic separation area of ​​another adjacent magnetic separation roller, the concentrate collection pipe is arranged at the lower side of the discharge area of ​​the last magnetic separation roller among the multiple magnetic separation rollers, and the discharge port of the hopper is arranged above the magnetic separation area of ​​the first magnetic separation roller of the multiple magnetic separation rollers.

[0008] Furthermore, taking the vertical line above the magnetic separation roller as the reference line, rotating clockwise along the reference line by an angle a is the magnetic separation zone, a=270°; rotating counterclockwise along the reference line by an angle b is the discharge zone, b=90°.

[0009] Furthermore, the horizontal spacing between two adjacent magnetic separation rollers among the plurality of magnetic separation rollers is 8 mm-10 mm, and the vertical spacing between the center lines of two adjacent magnetic separation rollers is 100 mm-120 mm.

[0010] Furthermore, a plurality of the scraper strips are evenly distributed on the circumference of the outer wall of the outer cylinder, and along the circumferential direction of the outer wall of the outer cylinder, the circumferential arc distance between two adjacent scraper strips is 100mm-120mm.

[0011] Furthermore, the sealed box body includes a top sealing steel plate, a bottom sealing steel plate and a side sealing steel plate. The side sealing steel plates are arranged around the sealed box body, the side sealing steel plates are connected to the lower end of the top sealing steel plate, the bottom sealing steel plate is connected to the lower end of the side sealing steel plate, the bottom sealing steel plate is funnel-shaped, the tailings discharge port is arranged at the lowest point of the funnel shape of the bottom sealing steel plate, the concentrate collecting pipe is connected to the side sealing steel plate, and a plurality of brackets are fixedly connected to the lower end of the bottom sealing steel plate.

[0012] Furthermore, the hopper is connected to the top sealing steel plate, the hopper discharge port is connected to a screw feeder, the screw feeder discharge port is connected to a vibrating distributor, the vibrating distributor discharge port is arranged inside the sealed box, the vibrating distributor discharge port is arranged above the magnetic separation zone of the first magnetic separation roller of multiple magnetic separation rollers, and the length of the vibrating distributor discharge port is the same as the length of the magnetic separation roller.

[0013] Furthermore, the material of the scraper strip is a non-magnetic wear-resistant material, the cross-section of the scraper strip is rectangular, the width of the cross-section of the scraper strip is 5mm-6mm, and the height of the cross-section of the scraper strip is 3mm-5mm; the material of the magnetic system is neodymium iron boron Nd-Fe-B material.

[0014] Furthermore, if the iron grade of the magnetic material is greater than 40%, 1-2 magnetic separation rollers are set; if the iron grade of the magnetic material is 20%<40%, 3-4 magnetic separation rollers are set; if the iron grade of the magnetic material is less than 20%, 3-4 magnetic separation rollers are set in each sealed box, and two sealed boxes are connected in series.

[0015] Furthermore, the number of the multiple magnetic separation rollers is four, the magnetic induction intensity of the first magnetic separation roller is 3000oe-3500 oe; the magnetic induction intensity of the second magnetic separation roller is 2500oe-3000 oe; the magnetic induction intensity of the third magnetic separation roller is 2000oe-2500 oe; the magnetic induction intensity of the first magnetic separation roller is 1500oe-1800 oe.

[0016] The present invention provides a magnetic separation process of a multi-roller permanent magnetic dry magnetic separator, comprising the following steps: S1. Add magnetic materials to the hopper. The magnetic materials mainly include iron ore, iron ore direct reduction materials, and iron-containing dust ash. The main types of iron ore include magnetite and magnetized roasted ore. The particle size of the magnetic materials is required to be less than 3 mm. The magnetic materials must be dried in a dryer before adding them to the hopper. The drying medium temperature is required to be 300℃-400℃, the drying time is required to be 40 min-60min, and the mechanical water content of the magnetic materials after drying is less than 2%; S2. After the magnetic material in the hopper is quantitatively fed by the screw feeder, the magnetic material falls to the vibrating distributor under the action of gravity; S3. The vibrating distributor evenly spreads the magnetic material on the outer cylinder surface along the width direction of the upper surface of the outer cylinder of the first magnetic separation roller. The magnetic material is magnetized by the magnetic induction intensity of the magnetic system of the first magnetic separation roller and is adsorbed on the outer cylinder surface. S4. During the rotation of the outer cylinder of the multiple magnetic separation rollers, relative motion occurs between the magnetic system and the outer cylinder. Under the action of the scraper bar, the magnetic material undergoes multiple magnetic flips along the lower surface of the outer cylinder. During the flipping process, the non-magnetic material mixed in the magnetic material is separated from the material under the action of gravity and falls into the funnel-shaped bottom sealing steel plate under the action of gravity and enters the tailings sealed silo through the tailings discharge port for collection; S5. After the separated magnetic materials are transported to the unloading area with the rotation of the outer cylinder, the magnetic materials are not affected by the magnetic induction intensity of the magnetic system in the unloading area. After the magnetic materials are separated from the outer cylinder of the first magnetic separation roller, they fall under the action of gravity. Under the action of the magnetic induction intensity of the magnetic system of the adjacent magnetic separation roller, the magnetic materials are adsorbed onto the outer cylinder surface of the adjacent magnetic separation roller. The magnetic materials are further advanced to step S4 on the adjacent magnetic separation roller. S6. Repeat steps S4 and S5 between multiple magnetic separation rollers to continuously improve the iron grade of the magnetic material, and finally obtain iron concentrate. The linear velocity of the outer wall of the outer cylinder of the magnetic separation roller in steps S4 and S5 is 0.2 m / s-0.5m / s; S7. After the iron concentrate enters the unloading area of ​​the last magnetic separation roller, the iron concentrate is not affected by the magnetic induction strength of the magnetic system in the unloading area. After the iron concentrate is separated from the outer cylinder, it falls into the concentrate collection pipe under the action of gravity and enters the concentrate sealed silo through the concentrate discharge port; S8. The non-magnetic materials falling from each magnetic separation roller pass through the bottom sealing steel plate and the tailings discharge port into the tailings sealed silo to obtain tailings.

[0017] The beneficial effects of the present invention are as follows: a plurality of magnetic separation rollers are connected inside the sealed box body, each magnetic separation roller comprises a roller shaft, a wheel hub, an inner cylinder, an outer cylinder, a scraper strip and a magnetic system, the roller shaft is rotatably connected to the sealed box body, the inner cylinder is fixedly connected to the wheel hub, the wheel hub is fixedly connected to the sealed box body, the magnetic system is fixedly connected to the outer wall of the inner cylinder, the outer cylinder is fixedly connected to the roller shaft, the outer cylinder is rotatably connected to the outside of the magnetic system, the scraper strip is fixedly connected to the outer wall of the outer cylinder, a part of the magnetic system is arranged on the outer wall of the inner cylinder along the circumferential direction, the area where the magnetic system is arranged forms a magnetic separation area, the area where the magnetic system is not arranged forms a discharge area, the discharge area of ​​each magnetic separation roller is close to the magnetic separation area of ​​another adjacent magnetic separation roller, the arrangement of the plurality of magnetic separation rollers of the present invention enables the plurality of magnetic separation rollers to be continuously separated by the plurality of magnetic systems, and the magnetic material is magnetically separated by the plurality of magnetic systems to obtain an iron concentrate with a higher grade, the present invention achieves the effects of improving the grade of the iron concentrate and improving the separation efficiency, and solves the problem of low metal recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a structural schematic diagram of the magnetic separation roller of the present invention; Figure 3 It is a structural schematic diagram of the magnetic separation area and the discharge area of ​​the magnetic separation roller of the present invention; Figure 4 It is a process flow chart of the present invention.

[0019] In the figure: 1. Sealing box; 101. Top sealing steel plate; 102. Bottom sealing steel plate; 103. Side sealing steel plate; 104. Concentrate collecting pipe; 105. Tailings discharge port; 106. Concentrate discharge port; 2. Magnetic separation roller; 201. Roller shaft; 202. Hub; 203. Inner cylinder; 204. Outer cylinder; 205. Scraper bar; 206. Magnetic system; 207. Magnetic separation area; 208. Discharging area; 3. Hopper; 4. Screw feeder; 5. Vibrating distributor; 6. Tailings sealed silo; 7. Concentrate sealed silo; 8. Bracket. DETAILED DESCRIPTION

[0020] like Figure 1-Figure 3As shown, a multi-roller permanent magnetic dry-type magnetic separator of the present invention includes a sealed box body 1, and the sealed box body 1 includes a top sealing steel plate 101, a bottom sealing steel plate 102 and a side sealing steel plate 103. The side sealing steel plate 103 is arranged around the sealed box body 1, and the side sealing steel plate 103 is connected to the lower end of the top sealing steel plate 101, and the bottom sealing steel plate 102 is connected to the lower end of the side sealing steel plate 103. The bottom sealing steel plate 102 is funnel-shaped, and a hopper 3 is connected to the top of the sealed box body 1. A plurality of magnetic separation rollers 2 are connected inside the sealed box body 1. The plurality of magnetic separation rollers 2 are linearly evenly distributed in the horizontal direction, and the plurality of magnetic separation rollers 2 are linearly evenly distributed in the vertical direction. The plurality of magnetic separation rollers 2 all rotate in a clockwise direction. The hopper 3 is arranged above the first magnetic separation roller 2 of the plurality of magnetic separation rollers 2. The hopper 3 The hopper 3 is connected to the top sealing steel plate 101, the discharge port is connected to the spiral feeder 4, the discharge port of the spiral feeder 4 is connected to the vibrating distributor 5, the discharge port of the vibrating distributor 5 is arranged inside the sealing box 1, the discharge port of the vibrating distributor 5 is arranged above the magnetic separation area 207 of the first magnetic separation roller 2 of the multiple magnetic separation rollers 2, the discharge port of the vibrating distributor 5 is the same as the length of the magnetic separation roller 2, the sealing box 1 is provided with a concentrate collecting pipe 104, the concentrate collecting pipe 104 is arranged on the side and below the last magnetic separation roller 2 of the multiple magnetic separation rollers 2, the heights of the multiple magnetic separation rollers 2 in the vertical direction from the hopper 3 to the concentrate collecting pipe 104 are successively reduced, the concentrate collecting pipe 104 is connected to the side sealing steel plate 103, and a concentrate discharge port 106 is arranged below the concentrate collecting pipe 104 A concentrate sealed silo 7 is provided outside the sealed box body 1, and a concentrate discharge port 106 extends into the concentrate sealed silo 7. A tailings discharge port 105 is provided at the lower part of the sealed box body 1, and the tailings discharge port 105 is arranged at the lowest point of the funnel-shaped bottom sealing steel plate 102. A tailings sealed silo 6 is provided outside the sealed box body 1, and the tailings discharge port 105 extends out of the tailings sealed silo 6. Each magnetic separation roller 2 includes a roller shaft 201, a hub 202, an inner cylinder 203, an outer cylinder 204, a scraper strip 205 and a magnetic system 206. The roller shaft 201 is rotatably connected to the sealed box body 1, the inner cylinder 203 is fixedly connected to the hub 202, the hub 202 is fixedly connected to the sealed box body 1, the magnetic system 206 is fixedly connected to the outer wall of the inner cylinder 203, and the outer cylinder 204 is fixedly connected to the roller shaft 201. On the shaft 201, the outer cylinder 204 is rotatably connected to the outside of the magnetic system 206, and the scraper strip 205 is fixedly connected to the outer wall of the outer cylinder 204. A part of the magnetic system 206 is set on the outer wall of the inner cylinder 203 along the circumferential direction. The area where the magnetic system 206 is set forms a magnetic separation area 207, and the area where the magnetic system 206 is not set forms a discharge area 208. The discharge area 208 of each magnetic separation roller 2 is close to the magnetic separation area 207 of another adjacent magnetic separation roller 2. The concentrate collection pipe 104 is set at the lower side of the discharge area 208 of the last magnetic separation roller 2 among the multiple magnetic separation rollers 2. The discharge port of the hopper 3 is set above the magnetic separation area 207 of the first magnetic separation roller 2 of the multiple magnetic separation rollers 2. There are multiple scraper strips 205 evenly distributed on the outer wall of the outer cylinder 204 along the circumferential direction of the outer wall of the outer cylinder 204.The circumferential arc distance between two adjacent scraper strips 205 is 100mm-120mm, and a plurality of brackets 8 are fixedly connected to the lower end of the bottom sealing steel plate 102.

[0021] The scraper strip 205 is made of non-magnetic wear-resistant material, the cross section of the scraper strip 205 is rectangular, the width of the cross section of the scraper strip 205 is 5mm-6mm, and the height of the cross section of the scraper strip 205 is 3mm-5mm; the material of the magnetic system 206 is neodymium iron boron Nd-Fe-B material.

[0022] The cross section of the scraper strip 205 is rectangular, which is convenient for transferring materials between the two magnetic separation rollers 2. When the cross section of the scraper strip 205 is rectangular, the contact area between the scraper strip 205 and the roller surface of the magnetic separation roller 2 is larger, which improves the bonding effect of the scraper strip 205 on the roller surface of the magnetic separation roller. If the cross section of the scraper strip 205 is circular, the contact area between the scraper strip 205 and the roller surface of the magnetic separation roller 2 is a line, and the bonding effect of the scraper strip 205 on the roller surface of the magnetic separation roller 2 is not good. The width of the cross section of the scraper strip 205 is 5mm-6mm, so that the scraper strip 205 can scrape away the material without having a significant impact on the output. When the width of the cross section of the scraper strip 205 is wider, after the scraper strip 205 adheres to the magnetic separation surface of the magnetic separation roller 2, it occupies more of the magnetic separation surface of the magnetic separation roller 2, resulting in a decrease in production; but when the width of the cross section of the scraper strip 205 is narrower, after the scraper strip 205 adheres to the magnetic separation surface of the magnetic separation roller 2, its adhesion strength is lower, and the scraper strip 205 is prone to falling off during production; when the height of the cross section of the scraper strip 205 is smaller, the magnetic material cannot be scraped from the magnetic area to the non-magnetic area, but when the height of the cross section of the scraper strip 205 is higher, friction will occur between the magnetic separation surfaces of two adjacent magnetic separation rollers 2.

[0023] Taking the vertical line above the magnetic separation roller 2 as the reference line, rotating clockwise along the reference line by an angle a is the magnetic separation zone 207, a=270°; rotating counterclockwise along the reference line by an angle b is the discharge zone 208, b=90°.

[0024] The horizontal spacing between two adjacent magnetic separation rollers 2 among the plurality of magnetic separation rollers 2 is 8 mm-10 mm, and the vertical spacing between the center lines of two adjacent magnetic separation rollers 2 is 100 mm-120 mm.

[0025] Since the particle size of the magnetic material is below 3mm, when the surfaces of two adjacent magnetic separation rollers 2 are covered with materials, the thickness of the material layer between the two adjacent magnetic separation rollers 2 is 6mm. When the two adjacent magnetic separation rollers 2 rotate, in order to avoid friction between the materials, a gap of 2-4mm is required between the materials. However, when this gap is too large, the material unloaded by the previous magnetic separation roller 2 may not be adsorbed by the next magnetic separation roller 2. Therefore, the horizontal spacing between the two adjacent magnetic separation rollers 2 in the present invention is controlled to be 8mm-10mm.

[0026] When the magnetic separation roller 2 is unloading, the material has a discharge length in the vertical direction. In order to allow the material unloaded by the previous magnetic separation roller 2 to be adsorbed by the next magnetic separation roller 2, the vertical spacing between the center lines of two adjacent magnetic separation rollers 2 has a minimum value. However, when the vertical spacing between the center lines of adjacent magnetic separation rollers 2 is too large, the vertical drop height of the material unloaded by the previous magnetic separation roller 2 increases, which not only easily generates dust, but also increases the falling speed of the material, which is not conducive to the adsorption of the magnetic material by the next magnetic separation roller 2. Therefore, the vertical spacing between the center lines of two adjacent magnetic separation rollers 2 is controlled to be 100mm-120mm.

[0027] If the iron grade of the magnetic material is greater than 40%, 1-2 magnetic separation rollers 2 are set; if the iron grade of the magnetic material is 20% less than 40%, 3-4 magnetic separation rollers 2 are set; if the iron grade of the magnetic material is less than 20%, 3-4 magnetic separation rollers 2 are set in each sealed box 1, and two sealed boxes 1 are connected in series.

[0028] When the iron grade of the magnetic material is greater than 40%, it means that the content of non-magnetic materials in the magnetic material is relatively low. At this time, the dry separation of the magnetic material does not require a large magnetic separation surface area. Generally, 1-2 magnetic separation rollers 2 are set to meet the product quality requirements; when the iron grade of the magnetic material is 20%<40%, it means that the content of non-magnetic materials in the magnetic material is relatively high. At this time, the dry separation of the magnetic material requires a larger magnetic separation surface area. Generally, 3-4 magnetic separation rollers 2 are set to meet the product quality requirements; when the iron grade of the magnetic material is less than 20%, it means that the content of non-magnetic materials in the magnetic material is very high. At this time, the dry separation of the magnetic material requires a larger magnetic separation surface area. Generally, 3-4 magnetic separation rollers 2 are set in each sealed box 1, and two sealed boxes 1 are connected in series to meet the product quality requirements.

[0029] When there are four magnetic separation rollers 2, the magnetic induction intensity of the first magnetic separation roller 2 is 3000oe-3500 oe; the magnetic induction intensity of the second magnetic separation roller 2 is 2500oe-3000 oe; the magnetic induction intensity of the third magnetic separation roller 2 is 2000oe-2500oe; and the magnetic induction intensity of the first magnetic separation roller 2 is 1500oe-1800oe.

[0030] The magnetic induction intensity of the first magnetic separation roller 2 of the present invention is the highest, and then the magnetic induction intensity of the second magnetic separation roller 2, the third magnetic separation roller 2, and the fourth magnetic separation roller 2 decreases in sequence. This is mainly because the iron grade of the magnetic material is continuously improved after passing through each magnetic separation roller 2 for magnetic separation. After the iron grade of the material is improved, its magnetism will be enhanced. In order to avoid the difficulty of dry magnetic separation caused by the large magnetic agglomeration of the material with strong magnetism, the present invention sets a limit on the upper limit of the magnetic induction intensity of each magnetic separation roller 2 according to the difference in material magnetism caused by the material grade, in order to improve the dry magnetic separation effect of the magnetic material. However, when the magnetic induction intensity of each magnetic separation roller is low, it will cause the loss of weak magnetic minerals in the dry magnetic separation process, which will reduce the metal recovery rate in the magnetic separation process.

[0031] Multiple magnetic separation rollers 2 can be driven individually, and one of the magnetic separation rollers 2 is set as a driving roller. One end of the magnetic separation roller 2 that is a driving roller is connected to a motor and a search machine. The magnetic separation roller 2 that is a driving roller and the other magnetic separation roller 2 brackets can be driven by various rotation methods such as sprocket chain transmission.

[0032] like Figure 4 As shown, the magnetic separation process of a multi-roller permanent magnetic dry magnetic separator of the present invention includes the following steps: S1. Add magnetic materials to hopper 3. The magnetic materials mainly include iron ore, direct reduction materials of iron ore, and iron-containing dust ash. The main types of iron ore include magnetite and magnetized roasted ore. The particle size of the magnetic material is required to be less than 3 mm. The magnetic material is dried in a dryer before being added to hopper 3. The drying medium temperature is required to be 300°C-400°C, the drying time is 40 min-60min, and the mechanical water content of the magnetic material after drying is less than 2%; S2. After the magnetic material in the hopper 3 is quantitatively fed by the screw feeder 4, the magnetic material falls to the vibrating distributor 5 under the action of gravity; S3. The vibrating distributor 5 evenly spreads the magnetic material on the surface of the outer cylinder 204 along the width direction of the upper surface of the outer cylinder 204 of the first magnetic separation roller 2. The magnetic material is magnetized by the magnetic induction intensity of the magnetic system 206 of the first magnetic separation roller 2 and is adsorbed on the surface of the outer cylinder 204; S4. During the rotation of the outer cylinder 204 of the plurality of magnetic separation rollers 2, relative motion is generated with the magnetic system 206. During the circular motion of the magnetic material together with the outer cylinder 204 under the action of the scraper strip 205, the magnetic material undergoes multiple magnetic flips along the lower surface of the outer cylinder 204. During the flipping process, the non-magnetic material mixed in the magnetic material is separated from the material under the action of gravity and falls into the funnel-shaped bottom sealing steel plate 102 under the action of gravity and enters the tailings sealing silo 6 through the tailings discharge port 105 for collection; S5. After the separated magnetic materials are transported to the unloading area 208 as the outer cylinder 204 rotates, the magnetic materials are not affected by the magnetic induction intensity of the magnetic system 206 in the unloading area 208. After the magnetic materials are separated from the outer cylinder 204 of the first magnetic separation roller 2, they fall under the action of gravity. Under the action of the magnetic induction intensity of the magnetic system 206 of the adjacent magnetic separation roller 2, the magnetic materials are adsorbed onto the surface of the outer cylinder 204 of the adjacent magnetic separation roller 2. The magnetic materials are again advanced to step S4 on the adjacent magnetic separation roller 2. S6. Repeat steps S4 and S5 between the plurality of magnetic separation rollers 2 to continuously improve the iron grade of the magnetic material, and finally obtain iron concentrate. The linear velocity of the outer wall of the outer cylinder 204 of the magnetic separation roller 2 in steps S4 and S5 is 0.2 m / s-0.5m / s; S7. After the iron concentrate enters the unloading area 208 of the last magnetic separation roller 2, the iron concentrate is not affected by the magnetic induction intensity of the magnetic system 206 in the unloading area 208. After the iron concentrate is separated from the outer cylinder 204, it falls into the concentrate collecting pipe 104 under the action of gravity and enters the concentrate sealed silo through the concentrate discharge port 106; S8. The non-magnetic materials falling from each magnetic separation roller 2 pass through the bottom sealing steel plate 102 and the tailings discharge port 105 into the tailings sealed silo 6 to obtain tailings.

[0033] During the magnetic separation process of magnetic materials, it is necessary to separate the non-magnetic materials and the magnetic materials in the magnetic materials. When the particle size of the magnetic materials is above 3 mm, the magnetic materials themselves cannot fully achieve the full dissociation of the magnetic materials and the non-magnetic materials, resulting in a decrease in the iron grade of the product after dry magnetic separation. Therefore, in step S1 of the present invention, the particle size of the magnetic material is required to be below 3 mm.

[0034] Since the particle size of the magnetic material is below 3mm, when the surfaces of two adjacent magnetic separation rollers 2 are covered with materials, the thickness of the material layer between the two adjacent magnetic separation rollers 2 is 6mm. When the two adjacent magnetic separation rollers 2 rotate, in order to avoid friction between the materials, a gap of 2-4mm is required between the materials. However, when this gap is too large, the material unloaded by the previous magnetic separation roller 2 may not be adsorbed by the next magnetic separation roller 2. Therefore, the horizontal spacing between the two adjacent magnetic separation rollers 2 in the present invention is controlled to be 8mm-10mm.

[0035] The mechanical water content of magnetic materials needs to be controlled below 2% before dry magnetic separation. However, when the mechanical water content in the magnetic materials exceeds 2%, the viscosity of the magnetic materials themselves will increase, thereby reducing the effect of dry magnetic separation. To reduce the mechanical water content in magnetic materials, dryer drying is generally adopted. The drying medium temperature of the magnetic material dryer is 300℃-400℃, and the drying time is 40min-60min. When the drying temperature of the magnetic material is high, the energy consumption of the system will increase. When the drying temperature of the magnetic material is low, the drying efficiency will decrease. At the same time, when the drying time is short, the moisture content in the dried material will be higher. When the drying time is long, the energy consumption of the system will increase.

[0036] When the magnetic material is magnetically separated on the outer wall of the outer cylinder of the magnetic separation roller 2, it takes a certain amount of time to separate the magnetic material from the non-magnetic material during the material turning process. When the linear speed of the outer wall of the outer cylinder of the magnetic separation roller is high, the separation of the magnetic material and the non-magnetic material cannot be achieved. When the linear speed of the outer wall of the outer cylinder of the magnetic separation roller is low, the output of the dry magnetic separator will be affected. Therefore, the present invention sets the linear speed of the outer wall of the outer cylinder 204 of the magnetic separation roller 2 at 0.2 m / s-0.5m / s.

[0037] Embodiment 1: Figure 1-Figure 3 As shown, the present invention is mainly for magnetic materials with an iron grade of 33%, wherein four magnetic separation rollers 2 are provided, the horizontal spacing between two adjacent magnetic separation rollers 2 is set to 9 mm, and the vertical spacing between the center lines of two adjacent magnetic separation rollers 2 is 110 mm; the width of the cross section of the scraper strip 205 is 6 mm, and the height of the cross section of the scraper strip 205 is 5 mm; 30 scraper strips 205 are provided on the outer cylinder 204 of each magnetic separation roller 2. In addition, in this embodiment, the magnetic separation roller 2 closest to the concentrate collection pipe 104 of the four magnetic separation rollers 2 is driven Roller, one end of this magnetic separation roller 2 is connected to a reducer and a motor, the other end of this magnetic separation roller 2 and the ends of the other magnetic separation rollers 2 on the same side are connected to sprockets, and the multiple sprockets are driven by chains; in this embodiment, the magnetic induction intensity of the magnetic system 206 of the first magnetic separation roller 2 is 3300oe, the magnetic induction intensity of the magnetic system 206 of the second magnetic separation roller 2 is 2800oe, the magnetic induction intensity of the magnetic system 206 of the third magnetic separation roller 2 is 2500oe, and the magnetic induction intensity of the magnetic system 206 of the fourth magnetic separation roller 2 is 1800oe.

[0038] The process of magnetic separation for magnetic materials with an iron grade of 33% in this embodiment is as follows: S1. Add magnetic material to hopper 3. The main magnetic material is iron ore with an iron grade of 33%. The particle size of 500KG of magnetic material is processed to 3mm, and then dried in a dryer. The drying medium temperature is 380°C, the drying time is 45min, and the mechanical moisture content of the magnetic material after drying is less than 1.4%; S2. After the magnetic material in the hopper 3 is quantitatively fed by the screw feeder 4, the magnetic material falls to the vibrating distributor 5 under the action of gravity; S3. The vibrating distributor 5 evenly spreads the magnetic material on the surface of the outer cylinder 204 along the width direction of the upper surface of the outer cylinder 204 of the first magnetic separation roller 2. The magnetic material is magnetized by the magnetic induction intensity of the magnetic system 206 of the first magnetic separation roller 2 and is adsorbed on the surface of the outer cylinder 204; S4. During the rotation of the outer cylinder 204 of the first magnetic separation roller 2, relative motion is generated between the outer cylinder 204 and the magnetic system 206. During the circular motion of the magnetic material together with the outer cylinder 204 under the action of the scraper bar 205, the magnetic material undergoes multiple magnetic flips along the lower surface of the outer cylinder 204. During the flipping process, the non-magnetic material mixed in the magnetic material is separated from the material under the action of gravity and falls into the funnel-shaped bottom sealing steel plate 102 under the action of gravity and enters the tailings sealing silo 6 through the tailings discharge port 105 for collection; S5. After the separated magnetic material is transported to the unloading area 208 of the first magnetic separation roller 2 as the outer cylinder 204 of the first magnetic separation roller 2 rotates, the magnetic material is not affected by the magnetic induction intensity of the magnetic system 206 in the unloading area 208. After the magnetic material is separated from the outer cylinder 204 of the first magnetic separation roller 2, during the falling process under the action of gravity, the magnetic material is adsorbed onto the surface of the outer cylinder 204 of the second magnetic separation roller 2 under the action of the magnetic induction intensity of the magnetic system 206 of the second magnetic separation roller 2; S6. The separated magnetic materials are transported to the unloading area 208 of the second magnetic separation roller 2 as the outer cylinder 204 of the second magnetic separation roller 2 rotates. In the unloading area 208, the magnetic materials are not affected by the magnetic induction intensity of the magnetic system 206. After the magnetic materials are separated from the outer cylinder 204 of the second magnetic separation roller 2, they fall under the action of gravity. In the process, the magnetic materials are adsorbed onto the surface of the outer cylinder 204 of the third magnetic separation roller 2 under the action of the magnetic induction intensity of the magnetic system 206 of the third magnetic separation roller 2. The separated magnetic materials are transported to the unloading area 208 of the second magnetic separation roller 2 as the outer cylinder 204 of the second magnetic separation roller 2 rotates. After the outer cylinder 204 of the selection roller 2 rotates and is transported to the unloading area 208 of the third magnetic separation roller 2, the magnetic materials are not affected by the magnetic induction intensity of the magnetic system 206 in the unloading area 208. After the magnetic materials are separated from the outer cylinder 204 of the third magnetic separation roller 2, they fall under the action of gravity. In the process, the magnetic materials are adsorbed onto the surface of the outer cylinder 204 of the fourth magnetic separation roller 2 under the action of the magnetic induction intensity of the magnetic system 206 of the fourth magnetic separation roller 2. The linear speed of the outer wall of the outer cylinder 204 of the four magnetic separation rollers 2 is 0.4 m / s. S7. After the iron concentrate enters the unloading area 208 of the fourth magnetic separation roller 2, the iron concentrate is not affected by the magnetic induction intensity of the magnetic system 206 in the unloading area 208. After the iron concentrate is separated from the outer cylinder 204, it falls into the concentrate collecting pipe 104 under the action of gravity and enters the concentrate sealed silo through the concentrate discharge port 106; S8. The non-magnetic materials falling from each magnetic separation roller 2 pass through the bottom sealing steel plate 102 and the tailings discharge port 105 into the tailings sealed silo 6 to obtain tailings.

[0039] In this embodiment, after using the above-mentioned equipment and magnetic separation process, 500KG of magnetic material obtained 233.75KG of iron concentrate with an iron grade of 60%. If the same 500KG of magnetic material is beneficiated using the horizontal wind-magnetic separation machine of the prior art, only 220KG of iron concentrate with an iron grade of 60% can be obtained.

[0040] The same magnetic material was used to be separated by the equipment and process of the present invention and the horizontal wind-magnetic concentrator of the prior art, and the following comparative data were obtained: .

Claims

1. A multi-roller permanent magnetic dry magnetic separator, characterized in that: The invention comprises a sealed box body (1), a hopper (3) connected to the top of the sealed box body (1), a plurality of magnetic separation rollers (2) connected inside the sealed box body (1), the plurality of magnetic separation rollers (2) being linearly evenly distributed in the horizontal direction, the plurality of magnetic separation rollers (2) being linearly evenly distributed in the vertical direction, the plurality of magnetic separation rollers (2) all rotating in a clockwise direction, the hopper (3) being arranged above the first magnetic separation roller (2) of the plurality of magnetic separation rollers (2), a concentrate collecting pipe (104) being arranged on the sealed box body (1), the concentrate collecting pipe (104) being arranged at the side and lower part of the last magnetic separation roller (2) of the plurality of magnetic separation rollers (2), and the concentrate collecting pipe (104) being arranged from the material to the ore collecting pipe (104) in the vertical direction. The heights of the plurality of magnetic separation rollers (2) are successively reduced in the direction from the bucket (3) to the concentrate collection pipe (104); a concentrate discharge port (106) is provided below the concentrate collection pipe (104); a concentrate sealed material bin (7) is provided outside the sealed box body (1); the concentrate discharge port (106) extends into the concentrate sealed material bin (7); a tailings discharge port (105) is provided at the bottom of the sealed box body (1); a tailings sealed material bin (6) is provided outside the sealed box body (1); the tailings discharge port (105) extends out of the tailings sealed material bin (6); each magnetic separation roller (2) comprises a roller shaft (201), a wheel hub (202), and a plurality of magnetic separation rollers (206). 2), an inner cylinder (203), an outer cylinder (204), a scraper strip (205) and a magnetic system (206), the roller shaft (201) is rotatably connected to the sealed box body (1), the inner cylinder (203) is fixedly connected to the hub (202), the hub (202) is fixedly connected to the sealed box body (1), the magnetic system (206) is fixedly connected to the outer wall of the inner cylinder (203), the outer cylinder (204) is fixedly connected to the roller shaft (201), the outer cylinder (204) is rotatably connected to the outside of the magnetic system (206), the scraper strip (205) is fixedly connected to the outer wall of the outer cylinder (204), and the magnetic system (206) is circumferentially connected to the outer wall of the outer cylinder (204). 206) A portion is provided on the outer wall of the inner cylinder (203), the area where the magnetic system (206) is provided forms a magnetic separation area (207), and the area where the magnetic system (206) is not provided forms a discharge area (208), the discharge area (208) of each magnetic separation roller (2) is close to the magnetic separation area (207) of another adjacent magnetic separation roller (2), the concentrate collection pipe (104) is provided at the lower side of the discharge area (208) of the last magnetic separation roller (2) among the multiple magnetic separation rollers (2), and the discharge port of the hopper (3) is provided above the magnetic separation area (207) of the first magnetic separation roller (2) among the multiple magnetic separation rollers (2).

2. A multi-roller permanent magnetic dry separator according to claim 1, characterized in that: Taking the vertical line above the magnetic separation roller (2) as the reference line, rotating clockwise along the reference line by an angle a is the magnetic separation zone (207), where a=270°; rotating counterclockwise along the reference line by an angle b is the discharge zone (208), where b=90°.

3. A multi-roller permanent magnetic dry separator according to claim 2, characterized in that: The horizontal spacing between two adjacent magnetic separation rollers (2) among the plurality of magnetic separation rollers (2) is 8 mm to 10 mm, and the vertical spacing between the center lines of two adjacent magnetic separation rollers (2) is 100 mm to 120 mm.

4. A multi-roller permanent magnetic dry separator according to claim 3, characterized in that: A plurality of the scraper strips (205) are evenly distributed on the circumference of the outer wall of the outer cylinder (204); along the circumferential direction of the outer wall of the outer cylinder (204), the circumferential arc distance between two adjacent scraper strips (205) is 100 mm-120 mm.

5. A multi-roller permanent magnetic dry separator according to claim 4, characterized in that: The sealed box body (1) comprises a top sealing steel plate (101), a bottom sealing steel plate (102) and a side sealing steel plate (103); the side sealing steel plates (103) are arranged around the sealed box body (1); the side sealing steel plates (103) are connected to the lower end of the top sealing steel plate (101); the bottom sealing steel plate (102) is connected to the lower end of the side sealing steel plates (103); the bottom sealing steel plate (102) is funnel-shaped; the tailings discharge port (105) is arranged at the lowest point of the funnel shape of the bottom sealing steel plate (102); the concentrate collecting pipe (104) is connected to the side sealing steel plates (103); and the lower end of the bottom sealing steel plate (102) is fixedly connected to a plurality of brackets (8).

6. A multi-roller permanent magnetic dry separator according to claim 5, characterized in that: The hopper (3) is connected to the top sealing steel plate (101), the feeding port of the hopper (3) is connected to a spiral feeder (4), the feeding port of the spiral feeder (4) is connected to a vibrating distributor (5), the feeding port of the vibrating distributor (5) is arranged inside the sealing box (1), the feeding port of the vibrating distributor (5) is arranged above the magnetic separation area (207) of the first magnetic separation roller (2) of the multiple magnetic separation rollers (2), and the length of the feeding port of the vibrating distributor (5) is the same as the length of the magnetic separation roller (2).

7. A multi-roller permanent magnetic dry separator according to claim 6, characterized in that: The material of the scraper strip (205) is a non-magnetic wear-resistant material, the cross section of the scraper strip (205) is rectangular, the width of the cross section of the scraper strip (205) is 5mm-6mm, and the height of the cross section of the scraper strip (205) is 3mm-5mm; the material of the magnetic system (206) is neodymium iron boron Nd-Fe-B material.

8. A multi-roller permanent magnetic dry separator according to claim 7, characterized in that: If the iron grade of the magnetic material is greater than 40%, 1 to 2 magnetic separation rollers (2) are provided; if the iron grade of the magnetic material is less than 20% and less than 40%, 3 to 4 magnetic separation rollers (2) are provided; if the iron grade of the magnetic material is less than 20%, 3 to 4 magnetic separation rollers (2) are provided in each sealed box (1), and two sealed boxes (1) are connected in series.

9. A multi-roller permanent magnetic dry separator according to claim 7, characterized in that: The number of the plurality of magnetic separation rollers (2) is four, the magnetic induction intensity of the first magnetic separation roller (2) is 3000oe-3500oe; the magnetic induction intensity of the second magnetic separation roller (2) is 2500oe-3000oe; the magnetic induction intensity of the third magnetic separation roller (2) is 2000oe-2500oe; the magnetic induction intensity of the first magnetic separation roller (2) is 1500oe-1800oe.

10. A magnetic separation process of a multi-roller permanent magnetic dry magnetic separator according to any one of claims 8 or 9, characterized in that: The steps include: S1. Adding magnetic materials to the hopper (3). The magnetic materials mainly include iron ore, iron ore direct reduction materials, and iron-containing dust ash. The main types of iron ore include magnetite and magnetized roasted ore. The particle size of the magnetic materials is required to be less than 3 mm. The magnetic materials must be dried in a dryer before being added to the hopper (3). The drying medium temperature is required to be 300°C-400°C, the drying time is required to be 40 min-60 min, and the mechanical water content of the magnetic materials after drying is less than 2%; S2. After the magnetic material in the hopper (3) is quantitatively fed by the screw feeder (4), the magnetic material falls to the vibrating distributor (5) under the action of gravity; S3. The vibrating distributor (5) evenly spreads the magnetic material on the surface of the outer cylinder (204) of the first magnetic separation roller (2) along the width direction of the upper surface of the outer cylinder (204). The magnetic material is magnetized under the action of the magnetic induction intensity of the magnetic system (206) of the first magnetic separation roller (2) and is adsorbed on the surface of the outer cylinder (204); S4. During the rotation of the outer cylinder (204) of the plurality of magnetic separation rollers (2), relative motion is generated with the magnetic system (206). During the circular motion of the magnetic material together with the outer cylinder (204) under the action of the scraper bar (205), the magnetic material undergoes multiple magnetic flips along the lower surface of the outer cylinder (204). During the flipping process, the non-magnetic material mixed in the magnetic material is separated from the material under the action of gravity and falls into the funnel-shaped bottom sealing steel plate (102) under the action of gravity and enters the tailings sealing silo (6) through the tailings discharge port (105) for collection; S5. After the separated magnetic material is transported to the unloading area (208) as the outer cylinder (204) rotates, the magnetic material is not affected by the magnetic induction intensity of the magnetic system (206) in the unloading area (208). After the magnetic material is separated from the outer cylinder (204) of the first magnetic separation roller (2), it falls under the action of gravity. Under the action of the magnetic induction intensity of the magnetic system (206) of the adjacent magnetic separation roller (2), the magnetic material is adsorbed onto the surface of the outer cylinder (204) of the adjacent magnetic separation roller (2). The magnetic material is again subjected to the process of step S4 on the adjacent magnetic separation roller (2); S6. Repeating steps S4 and S5 between the plurality of magnetic separation rollers (2) to continuously improve the iron grade of the magnetic material, and finally obtaining an iron concentrate, wherein the linear velocity of the outer wall of the outer cylinder (204) of the magnetic separation roller (2) in steps S4 and S5 is 0.2 m / s-0.5 m / s; S7. After the iron concentrate enters the discharge area (208) of the last magnetic separation roller (2), the iron concentrate is not affected by the magnetic induction intensity of the magnetic system (206) in the discharge area (208). After the iron concentrate is separated from the outer cylinder (204), it falls into the concentrate collection pipe (104) under the action of gravity and enters the concentrate sealed silo through the concentrate discharge port (106); S8. The non-magnetic materials falling from each magnetic separation roller (2) pass through the bottom sealing steel plate (102) and enter the tailings sealing silo (6) through the tailings discharge port (105) to obtain tailings.

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