Micro-powder dry magnetic separator capable of reducing eddy current heating and use method of micro-powder dry magnetic separator

Abstract

The invention discloses a micro-powder dry magnetic separator capable of reducing eddy current heating and a use method, and relates to the technical field of magnetic separators. A magnetic separation cavity is formed in the magnetic separation main body frame, a feeding pipe opening is formed in the top, and a tailing outlet and a concentrate outlet are formed in the bottom; the rotary magnetic roller assembly comprises a separation barrel and a magnetic system, the magnetic system comprises a plurality of fan-shaped magnetic conductive blocks, and the space between every two adjacent magnetic conductive blocks is filled with a high-resistance insulating material; the annular magnet exciting coil is embedded in the magnetic conducting block, and an alternating magnetic field perpendicular to the surface of the sorting barrel at the corresponding position is generated under the condition that the annular magnet exciting coil is powered on; the material distribution device comprises a vibration feeder and an inclined flow guide plate, and convex flow guide ribs which are distributed at equal intervals are arranged on the surface of the inclined flow guide plate; the bottom of the inclined guide plate positioned at the bottom is positioned on the feeding pipe orifice; and an inlet expanding piece is mounted at the bottom of the feeding pipe orifice, so that the technical problems that the heating of the cylinder body is influenced by vortex reduction in a non-opening manner and the feeding is non-uniform and uncontrollable are solved.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic separators, and in particular to a micro-powder dry magnetic separator capable of reducing eddy current heating and a use method thereof. Background Art

[0002] Dry magnetic separator is a kind of magnetic separation equipment for separating dry magnetic minerals. It is commonly used in industries such as ferrous metal mines. Conventional magnetic separators are generally used to remove non-magnetic or weakly magnetic minerals from magnetic minerals. The working principle of dry magnetic separator is based on the combined action of magnetic force and mechanical force. When the material enters the separation area, the magnetic material is magnetized and adsorbed on the surface of the cylinder under the action of the magnetic field, and is brought to the designated position as the cylinder rotates. Non-magnetic materials are not affected by the magnetic field and naturally flow to the other material port, thereby realizing the separation of magnetic materials from non-magnetic materials.

[0003] The phenomenon of induced current generated by electromagnetic induction inside the entire conductor of the magnetic separator is called eddy current phenomenon, which causes overheating of the separation cylinder that adsorbs the mineral material. The magnetic field generated by the eddy current may cause some metal particles to be repelled or attracted, thereby changing their movement trajectory.

[0004] In the prior art, CN202122363914.2 is a drum of a magnetic separator, which adopts a method of opening long slots and combining metal shielding materials to interrupt the electromagnetic induction that continuously generates eddy currents; however, this method makes it easy for the adsorbed metal materials to accumulate in the long slots, making it difficult to select and separate the magnetic materials.

[0005] At present, the magnetic separator still has the following problems:

[0006] 1. The material cannot be fed evenly, and the target magnetic metal is easily lost when the particles are piled up;

[0007] 2. Material feeding easily impacts the cylinder;

[0008] To this end, we provide a micro-powder dry magnetic separator and a method of use that can reduce eddy current heating to solve the above problems. Summary of the invention

[0009] The purpose of the present invention is to make up for the shortcomings of the prior art and provide a micro-powder dry magnetic separator and a method of use for reducing eddy current heating, so as to solve the technical problems of reducing eddy current affecting cylinder heating and uneven and uncontrollable feeding without opening holes.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0011] A micro powder dry magnetic separator for reducing eddy current heating, comprising:

[0012] A magnetic separation main frame, wherein a magnetic separation cavity is provided inside the magnetic separation main frame, a feed pipe opening is provided at the top, and a tailings outlet and a concentrate outlet are provided at the bottom; The rotating magnetic roller assembly includes a sorting cylinder and a magnetic system, wherein the magnetic system includes a plurality of fan-shaped magnetic conductive blocks which are arranged at intervals along the circumference, and high-resistance insulating materials are filled between adjacent magnetic conductive blocks; The annular excitation coil is embedded in the magnetic conductive block. When the annular excitation coil is energized, an alternating magnetic field perpendicular to the surface of the separation cylinder at the corresponding position is generated; The material distribution device includes a vibrating feeder and an inclined guide plate, wherein the surface of the inclined guide plate is provided with equidistantly distributed raised guide ribs; the bottom of the inclined guide plate located at the bottom is located on the feed pipe opening; an inlet expansion piece is installed at the bottom of the feed pipe opening; The temperature monitoring system includes an infrared sensor and a feedback controller, and the feedback controller regulates the rotation speed of the rotating magnetic roller assembly and the current frequency of the annular excitation coil.

[0013] In a further technical solution, a magnetic conductive cavity and a fixed column are provided in the magnetic conductive block, and the annular excitation coil is sleeved outside the fixed column;

[0014] The rotating magnetic roller assembly also includes a fixed plate and a central fixed cylinder. A guide cylinder is provided in the fixed plate. The power supply circuit and control circuit of the annular excitation coil are connected to the central fixed cylinder through the guide cylinder and extend to the outside of the magnetic separation main frame.

[0015] The sorting cylinder body is provided with a mounting cylinder part, which is mounted on the central fixed cylinder and connected by mounting a connecting bearing; a connecting groove is provided in the central fixed cylinder located in the mounting cylinder part; the outer ring of the connecting bearing is connected to the mounting cylinder part, and the inner ring of the connecting bearing is connected to the inner wall of the connecting groove;

[0016] The mounting cylinder is connected to an external driving structure so that the mounting cylinder rotates relative to the central fixed cylinder. The driving structure can be a belt wheel drive, a gear drive, a sprocket drive or other transmission methods. For example, the belt wheel method can be installed on the mounting cylinder of the sorting cylinder, and connected to the transmission belt driven by the external driving motor through a connecting transmission belt.

[0017] In a further technical solution, the magnetic conductive block includes silicon steel sheets, which are arranged in multiple groups and stacked layer by layer; a nano-aluminum oxide insulating coating is coated between the upper and lower silicon steel sheets, and the stacking direction is parallel to the axis of the central fixed cylinder.

[0018] In a further technical solution, the high resistance insulating material is a silicon carbide ceramic matrix composite material with a resistivity of >10^ 4 Ω·m, the difference between the thermal expansion coefficient of the high resistance insulating material and the thermal expansion coefficient of the magnetic block is less than 5%.

[0019] In a further technical solution, the magnetic system includes an upper arc plate, a pressing plate 1 and a pressing plate 2, the upper arc plate is fixed upward on the central fixed cylinder; the pressing plate 1 and the pressing plate 2 are both pressed tightly on the upper and lower sides of the multiple groups of magnetic conductive blocks, and the upper arc plate and the pressing plate 1 are connected by a connecting support plate;

[0020] The two ends of the first pressing plate and the second pressing plate are connected.

[0021] In a further technical solution, the inclined guide plate is provided in multiple layers and is located on the output end of the vibrating feeder; and is inclined from top to bottom toward the feed pipe opening;

[0022] The height of the raised guide ribs is 3-5 mm, the inclined guide plates are distributed in multiple layers, and the spacing between adjacent raised guide ribs is 1.2-1.5 times the average particle size of the mineral material.

[0023] In a further technical solution, the raised guide ribs include guide strips and fork strips, the guide strips are arranged obliquely along the surface of the inclined guide plate, and the fork strips are arranged in multiple groups.

[0024] In a further technical solution, the feedback controller dynamically adjusts the rotation speed according to the temperature data so that the eddy current loss power satisfies the formula:

[0025]

[0026] Where k is the material constant, B is the magnetic induction intensity, f is the current frequency, and δ is the width of the gap between the magnetic blocks.

[0027] In a further technical solution, a fixing frame is installed on the magnetic separation main frame, and a laser particle size counter is installed on the fixing frame;

[0028] The inlet expansion member comprises two groups of symmetrically distributed baffle plates, the top ends of the two groups of baffle plates are provided with hinge interfaces, and are installed in the magnetic separation main frame through the installation shaft;

[0029] A bidirectional lead screw is installed on the side of the feed pipe opening facing away from the hinge interface, and fixed blocks are arranged in the middle and at both ends of the bidirectional lead screw, and are fixed to the main frame of the magnetic separator; setting position bearings are installed in the fixed blocks at both ends, and are connected to the ends of the bidirectional lead screw, and a protective cover is installed at the bottom of the bidirectional lead screw;

[0030] A sliding groove is provided on the baffle plate, and a lower slider is installed in the sliding groove. The lower slider is restricted in the sliding groove and is rotatably connected to an upper nut seat, which moves on a bidirectional lead screw. A bevel gear box is installed at the end of the bidirectional lead screw, and a switch reduction motor is installed on the main frame of the magnetic separation to connect them.

[0031] A method for using a micro-powder dry magnetic separator for reducing eddy current heating comprises the following steps:

[0032] Step a. Start the rotating magnetic roller assembly, apply alternating current to the annular excitation coil through the central fixed cylinder and the guide cylinder after modulation by an external power supply device, and generate a radial alternating magnetic field perpendicular to the surface of the magnetic roller;

[0033] Initial state: The initial value of the magnetic induction intensity of the alternating magnetic field is 0.3-1.2T, the frequency is 50-150Hz, and the direction of the magnetic field is orthogonal to the direction of movement of the ore;

[0034] Step b. The ore is transported to the surface of the magnetic roller through a vibrating feeder and a multi-layer inclined guide plate. The wavy guide ribs of the guide plate disperse the ore in the axial direction of the magnetic roller to form a uniform material layer with a thickness fluctuation of ≤±1.5mm; the vibration frequency of the guide plate is 20 to 40Hz, the wavy period of the guide rib is 1.5 to 2 times the average particle size of the ore, and the inclination of the guide plate is adjustable in the range of 45° to 60°;

[0035] Step c. Real-time monitoring of the surface temperature distribution of the magnetic roller. When the local temperature exceeds the set threshold, the feedback controller simultaneously reduces the speed of the magnetic roller and increases the frequency of the excitation current. The feedback controller dynamically adjusts the speed according to the temperature data so that the eddy current loss power satisfies the formula:

[0036]

[0037] Care needs to be taken to determine its critical maximum value;

[0038] Step d. Detecting the particle concentration in the distribution device by a laser particle counter;

[0039] Step e. According to the detected concentration, the data is transmitted to the control cabinet for data analysis, and then the bevel gear box is controlled to drive the bidirectional screw to rotate by controlling the switch reduction motor, and the upper nut seats on both sides of the bidirectional screw move to both sides, driving the lower slider to move outward, driving the two sets of hinged baffle plates to rotate, thereby opening the connecting area with the feed pipe mouth, thereby controlling the feed speed;

[0040] Step f, synchronously, an infrared sensor is installed in the magnetic separation main frame to detect the surface temperature of the separation cylinder, and the transmission speed of the installation cylinder is controlled by the driving structure.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The alternating current used in the present invention changes the magnetic field in the annular excitation coil, which can adapt to the sorting requirements of different magnetic minerals without replacing the equipment hardware. The feedback controller can also respond to changes in the particle size and humidity of the ore in real time. The present invention installs high-resistance insulating materials between adjacent magnetic blocks to make the magnetic flux lines as vertical as possible to the vertical direction of the sorting cylinder, and interrupts the continuous magnetic induction brought by the traditional whole magnetic block, reducing the continuous increase of the eddy current phenomenon, thereby reducing the heating temperature and continuity of the eddy current on the sorting cylinder.

[0043] The present invention is arranged to drive the bidirectional screw to rotate through the bevel gears. When the two sets of upper nut seats on the bidirectional screw move to both sides, they rotate with the hinge interface as the center, driving the lower slider to move on the sliding groove to avoid getting stuck, thereby realizing the rotating switch effect under the feed pipe mouth and synchronously controlling the feed speed.

[0044] The present invention achieves the technical effect of uniform material discharge by installing multiple groups of inclined guide plates at the outlet of the vibrating feeder and performing inclined material discharge through raised guide ribs. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic cross-sectional structure diagram of the micro-powder dry magnetic separator of the present invention;

[0046] Figure 2 for Figure 1 A magnified view of part A;

[0047] Figure 3 This is a schematic structural diagram of an annular excitation coil installed in a magnetic conductive block according to Embodiment 1 of the present invention;

[0048] Figure 4 It is a structural schematic diagram of the separation cylinder of the present invention;

[0049] Figure 5 It is a schematic diagram of the magnetic system structure of the fixed plate and the central fixed cylinder of the present invention;

[0050] Figure 6 It is a cross-sectional schematic diagram of the connection between the central fixed cylinder and the sorting cylinder in the present invention;

[0051] Figure 7 It is a schematic diagram of the internal part of the vibrating feeder of the present invention;

[0052] Figure 8 for Figure 7 The enlarged structural diagram at B in the middle;

[0053] Fig. 9 It is a front view schematic diagram of the inclined flow guide device of embodiment 2 of the present invention;

[0054] Fig.10It is a schematic cross-sectional structural diagram of a micro-powder dry magnetic separator according to Example 3 of the present invention;

[0055] Fig.11 It is a top view schematic diagram of the inlet diameter expansion member under the feed pipe opening of the present invention;

[0056] Fig.12 It is a structural schematic diagram of the material baffle plate of the present invention.

[0057] In the figure:

[0058] 1. Main frame of magnetic separation; 11. Feeding pipe opening; 12. Tailings outlet; 13. Concentrate outlet;

[0059] 2. Rotating magnetic roller assembly; 21. Sorting cylinder; 22. Magnetic system; 23. Magnetic conductive block; 24. High resistance insulating material; 25. Fixed plate; 26. Central fixed cylinder; 27. Connecting bearing;

[0060] 211, installation cylinder; 231, fixing column; 251, guide cylinder; 232, silicon steel sheet; 233, nano-alumina insulation coating; 221, upper arc plate; 222, pressing plate 1; 223, pressing plate 2; 224, support plate;

[0061] 3. Ring excitation coil;

[0062] 4. Material distribution device; 41. Vibrating feeder; 42. Inclined guide plate; 43. Raised guide rib; 431. Guide strip; 432. Fork strip;

[0063] 5. Import expansion parts; 51. Baffle plate; 52. Hinge interface; 53. Bidirectional screw; 54. Fixed block; 55. Position bearing; 56. Protective cover; 57. Sliding groove; 58. Lower slide block; 59. Upper nut seat; 510. Bevel gear box; 511. Switch reduction motor;

[0064] 6. Temperature monitoring system; 61. Infrared sensor; 62. Feedback controller;

[0065] 7. Fixed frame; 71. Laser particle size counter; DETAILED DESCRIPTION

[0066] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] Example 1

[0068] See also Figure 1-8As shown, the present invention provides a technical solution, a micro-powder dry magnetic separator for reducing eddy current heating, comprising:

[0069] A magnetic separation main frame 1, wherein a magnetic separation cavity is provided inside the magnetic separation main frame 1, a feed pipe port 11 is provided at the top, and a tailings outlet 12 and a concentrate outlet 13 are provided at the bottom respectively; a rotating magnetic roller assembly 2, comprising a separation cylinder 21 and a magnetic system 22, wherein the magnetic system 22 comprises a plurality of fan-shaped magnetic conductive blocks 23 which are arranged at intervals along the circumference, and a high-resistance insulating material 24 is filled between adjacent magnetic conductive blocks 23; the separation cylinder 21 is located in the magnetic separation cavity; an annular excitation coil 3, which is embedded in the magnetic conductive blocks 23, and generates an alternating magnetic field perpendicular to the surface of the separation cylinder 21 at a corresponding position when the annular excitation coil 3 is energized; a material distribution device 4, comprising a vibrating feeder 41 and an inclined guide plate 42, wherein the surface of the inclined guide plate 42 is provided with equidistantly distributed raised guide ribs 43; the bottom of the inclined guide plate 42 at the bottom is located on the feed pipe port 11; an inlet expansion member 5 is installed at the bottom of the feed pipe port 11; The temperature monitoring system 6 includes an infrared sensor 61 and a feedback controller 62 . The feedback controller 62 regulates the rotation speed of the rotating magnetic roller assembly 2 and the current frequency of the annular excitation coil 3 .

[0070] like Figure 3 As shown, the magnetic conductive block 23 is provided with a magnetic conductive cavity and a fixing column 231, and the annular excitation coil 3 is sleeved outside the fixing column 231;

[0071] The rotating magnetic roller assembly 2 also includes a fixed plate 25 and a central fixed cylinder 26. A guide cylinder 251 is provided in the fixed plate 25. The power supply circuit and control circuit of the annular excitation coil 3 are connected to the central fixed cylinder 26 through the guide cylinder 251 and extend to the outside of the magnetic separation main frame 1.

[0072] The sorting cylinder 21 is provided with a mounting cylinder 211, which is mounted on the central fixed cylinder 26 and connected by mounting a connecting bearing 27; a connecting groove is provided in the central fixed cylinder 26 located in the mounting cylinder 211; the outer ring of the connecting bearing 27 is connected to the mounting cylinder 211, and the inner ring of the connecting bearing 27 is connected to the inner wall of the connecting groove;

[0073] The mounting cylinder 211 is connected to an external driving structure so that the mounting cylinder 211 rotates relative to the central fixed cylinder 26. The driving structure can be a belt drive, a gear drive, a sprocket drive, etc. For example, the belt drive can be installed on the mounting cylinder of the sorting cylinder, and connected to the transmission belt driven by the external driving motor through a connecting transmission belt. It is not drawn in the figure and should be designed in consideration of actual use.

[0074] The magnetic conductive block 23 includes silicon steel sheets 232 , which are arranged in multiple groups and stacked layer by layer. A nano-aluminum oxide insulating coating 233 is coated between the upper and lower silicon steel sheets 232 , and the stacking direction is parallel to the axis of the central fixed cylinder 26 .

[0075] The high resistance insulating material 24 is a silicon carbide ceramic-based composite material with a resistivity of more than 10^ 4 Ω·m, the difference between the thermal expansion coefficient of the high resistance insulating material 24 and the thermal expansion coefficient of the magnetic conductive block 23 is less than 5%.

[0076] like Figure 5 As shown, the magnetic system 22 includes an upper arc plate 221, a pressing plate 1 222 and a pressing plate 223. The upper arc plate 221 is fixed upward on the central fixed tube 26; the pressing plate 1 222 and the pressing plate 223 are both pressed on the upper and lower sides of the multiple groups of magnetic conductive blocks 23, and the upper arc plate 221 and the pressing plate 1 222 are connected by a connecting support plate 224; the two ends of the pressing plate 1 222 and the pressing plate 223 are connected.

[0077] Combination Figure 7 and Figure 8 As shown, the inclined guide plate 42 is provided in multiple layers and is located on the output end of the vibrating feeder 41; and is inclined from top to bottom toward the feed pipe opening 11;

[0078] The height of the raised guide ribs 43 is 3-5 mm, the inclined guide plates 42 are distributed in multiple layers, and the distance between adjacent raised guide ribs 43 is 1.2-1.5 times the average particle size of the mineral material.

[0079] The feedback controller 62 dynamically adjusts the rotation speed according to the temperature data so that the eddy current loss power satisfies the formula:

[0080]

[0081] Where k is the material constant, B is the magnetic induction intensity, f is the current frequency, and δ is the width of the gap between the magnetic blocks 23. The square term of B shows that the magnetic field intensity has the greatest impact on the loss, so controlling the magnetic field intensity is the key to reducing the loss. Setting the frequency f to the 1.5th power reflects the nonlinear growth of eddy current losses at high frequencies, which is related to the skin effect. The higher the frequency, the smaller the skin depth, but the loss increases faster. The negative exponent of δ shows that increasing the width of the dividing gap δ can significantly reduce the loss. This is because the increase in the gap interrupts the continuous path of the eddy current, reduces the flow area of ​​the eddy current, and thus reduces the loss. Split, where σ: material conductivity; d: thickness of a single magnetic block; η split: efficiency coefficient of split structure.

[0082] The design principle of the above formula:

[0083] First, the magnetic field strength (B2 ) Basis: In the classic eddy current loss formula, the loss is proportional to the square of the magnetic field strength. Since eddy currents are generated by the currents induced in the magnetic conductive material by the alternating magnetic field, their energy is directly related to the energy density of the magnetic field.

[0084] Where, setting frequency (f 1.5 ): Nonlinear correction: Eddy current loss and f in traditional theory 2 proportional to, but this formula is adjusted to f 1.5 The reasons include: magnetic block segmentation design: the gap (δ) blocks the eddy current path, inhibits the diffusion of eddy current at high frequency, and weakens the frequency influence; skin effect: at high frequency, the current is concentrated on the surface of the material, the equivalent conductive cross-sectional area is reduced, and the loss growth rate is slowed down.

[0085] Among them, setting the gap width ( ): Geometric blocking effect: Increasing the gap shortens the eddy current loop length and reduces the induced electromotive force; increasing the eddy current path resistance and reducing the eddy current intensity.

[0086] The advantages of this embodiment are:

[0087] 1. Magnetic pole division design

[0088] The sector-shaped magnetic blocks are isolated by high-resistance insulating materials, cutting off the continuous conductive loop and shortening the eddy current path length by more than 70%.

[0089] The laminated structure of silicon steel sheets limits the eddy currents to the inside of a single magnetic conductive block, and combined with the nano-alumina insulating coating, the eddy current losses are reduced to 18%-25% of that of traditional integral magnetic rollers.

[0090] 2. Uniform fabric synergy

[0091] The wave-shaped arrangement of the guide ribs produces a turbulent effect, making the standard deviation of the ore distribution uniformity less than 0.15 and avoiding sudden changes in local magnetic permeability.

[0092] Compared with the existing permanent magnet magnetic separation method, the present invention uses a ring-shaped excitation coil to generate an alternating current magnetic field, which has the following advantages:

[0093] 1. It can adapt to the separation requirements of different magnetic minerals (such as weakly magnetic hematite and strongly magnetic magnetite) without replacing equipment hardware;

[0094] 2. The feedback controller can respond to changes in mineral particle size and humidity in real time;

[0095] 3. Relative to the fixed magnetic field of the permanent magnet, the coil winding direction and current polarity can be programmably controlled to achieve flexible switching of radial, axial or composite magnetic fields.

[0096] The present invention installs high-resistance insulating materials between adjacent magnetic blocks to make the magnetic flux lines as perpendicular to the vertical direction of the sorting cylinder as possible, interrupt the continuous magnetic induction brought by the traditional whole magnetic blocks, reduce the continuous increase of eddy current phenomenon, and thus reduce the heating temperature and continuity of the sorting cylinder by the eddy current.

[0097] Example 2

[0098] like Fig. 9 As shown, another embodiment of the present invention is provided. On the basis of Example 1, raised guide ribs that can slide down to make the mineral material uniform are provided. The raised guide ribs 43 include guide bars 431 and fork bars 432. The guide bars 431 are inclined along the surface of the inclined guide plate 42, and the fork bars 432 are provided in multiple groups.

[0099] Example 3

[0100] like Figure 10-12 As shown, it is another embodiment of the present invention. On the basis of Example 1, a fixing frame 7 is installed on the magnetic separation main frame 1, and a laser particle size counter 71 is installed on the fixing frame 7;

[0101] The inlet expansion member 5 comprises two groups of symmetrically distributed baffle plates 51, the top ends of the two groups of baffle plates 51 are provided with hinge ports 52, and are installed in the magnetic separation main frame 1 through the installation shaft;

[0102] like Fig.11 , Fig.11 The figure is a schematic diagram of the structure of the inlet expansion part under the feed pipe mouth in a top-down perspective. A bidirectional lead screw 53 is installed on the side of the feed pipe mouth 11 facing away from the hinge port 52, and fixed blocks 54 are provided in the middle and both ends of the bidirectional lead screw 53, and are fixed to the magnetic separation main frame 1; setting position bearings 55 are installed in the fixed blocks 54 at both ends, and are connected to the ends of the bidirectional lead screw 53, and a protective cover 56 is installed at the bottom of the bidirectional lead screw 53; in terms of feed closure, it is possible to consider designing the two sets of baffle plates to fit together.

[0103] A slide groove 57 is provided on the baffle plate 51, and a lower slider 58 is installed in the slide groove 57. The lower slider 58 is limited in the slide groove 57 and an upper nut seat 59 is rotatably connected to the lower slider 58. The upper nut seat 59 moves on the bidirectional lead screw 53. A bevel gear box 510 is installed at the end of the bidirectional lead screw 53, and a switch reduction motor 511 is installed on the magnetic separation main frame 1. When the two sets of upper nut seats on the bidirectional lead screw move to both sides, they rotate around the hinge interface as the center, driving the lower slider to move on the slide groove to avoid getting stuck and achieve the effect of rotating the switch.

[0104] A method for using a micro-powder dry magnetic separator for reducing eddy current heating comprises the following steps:

[0105] Step a. Start the rotating magnetic roller assembly 2, and apply an alternating current to the annular excitation coil 3 through the central fixed cylinder 26 and the guide cylinder 251 after modulation by an external power supply device, to generate a radial alternating magnetic field perpendicular to the surface of the magnetic roller;

[0106] Initial state: The initial value of the magnetic induction intensity of the alternating magnetic field is 0.3-1.2T, the frequency is 50-150Hz, and the direction of the magnetic field is orthogonal to the direction of movement of the ore;

[0107] Step b. The ore is transported to the surface of the magnetic roller by a vibrating feeder 41 and a multi-layer inclined guide plate 42. The raised guide ribs 43 of the inclined guide plate 42 disperse the ore in the axial direction of the magnetic roller to form a uniform material layer with a thickness fluctuation of ≤±1.5 mm; the vibration frequency of the inclined guide plate is 20 to 40 Hz, the wave-shaped period of the raised guide ribs is 1.5 to 2 times the average particle size of the ore, and the inclination of the guide plate is adjustable in the range of 45° to 60°;

[0108] Step c. Real-time monitoring of the surface temperature distribution of the magnetic roller. When the local temperature exceeds the set threshold, the feedback controller 62 simultaneously reduces the speed of the magnetic roller and increases the excitation current frequency; the feedback controller 62 dynamically adjusts the speed according to the temperature data so that the eddy current loss power satisfies the formula:

[0109]

[0110] Care needs to be taken to determine its critical maximum value;

[0111] Step d. Detecting the particle concentration in the distribution device 4 by means of a laser particle counter 71;

[0112] Step e. According to the detected concentration, the data is transmitted to the control cabinet for data analysis, and then the bevel gear box 510 is controlled to drive the bidirectional screw 53 to rotate by controlling the switch reduction motor 511, and the upper nut seats 59 on both sides of the bidirectional screw 53 move to both sides, driving the lower slider 58 to move outward, driving the two sets of hinged baffle plates 51 to rotate, thereby opening the communication area with the feed pipe port 11, thereby controlling the feed speed;

[0113] Step f, synchronously, an infrared sensor 61 is installed in the magnetic separation main frame 1 to detect the surface temperature of the separation cylinder 21, and the transmission speed of the installation cylinder 211 is controlled by the driving structure.

[0114] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0115] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A micro powder dry magnetic separator for reducing eddy current heating, characterized in that: include: A magnetic separation main frame (1), wherein a magnetic separation cavity is provided inside the magnetic separation main frame (1), a feed pipe opening (11) is provided at the top, and a tailings outlet (12) and a concentrate outlet (13) are provided at the bottom; The rotating magnetic roller assembly (2) comprises a separation cylinder (21) and a magnetic system (22), wherein the magnetic system (22) comprises a plurality of fan-shaped magnetic conductive blocks (23) arranged at intervals along the circumference, and high-resistance insulating material (24) is filled between adjacent magnetic conductive blocks (23); the separation cylinder (21) is located in the magnetic separation cavity; The annular excitation coil (3) is embedded in the magnetic conductive block (23), and generates an alternating magnetic field perpendicular to the surface of the separation cylinder (21) at a corresponding position when the annular excitation coil (3) is energized; The material distribution device (4) comprises a vibrating feeder (41) and an inclined guide plate (42), wherein the surface of the inclined guide plate (42) is provided with equidistantly distributed raised guide ribs (43); the bottom of the inclined guide plate (42) located at the bottom is located on the feed pipe opening (11); an inlet diameter expansion member (5) is installed at the bottom of the feed pipe opening (11); The temperature monitoring system (6) comprises an infrared sensor (61) and a feedback controller (62), wherein the feedback controller (62) regulates the rotation speed of the rotating magnetic roller assembly (2) and the current frequency of the annular excitation coil (3).

2. A micro powder dry magnetic separator for reducing eddy current heating according to claim 1, characterized in that: The magnetic conductive block (23) is provided with a magnetic conductive cavity and a fixed column (231), and the annular excitation coil (3) is sleeved outside the fixed column (231); The rotating magnetic roller assembly (2) further comprises a fixed plate (25) and a central fixed cylinder (26); a guide cylinder (251) is provided in the fixed plate (25); a power supply circuit and a control circuit of the annular excitation coil (3) are connected to the central fixed cylinder (26) via the guide cylinder (251) and extend to the outside of the magnetic separation main frame (1); The separation cylinder (21) is provided with a mounting cylinder portion (211), which is mounted on the central fixed cylinder (26) and connected via a mounting connecting bearing (27); a connecting groove is provided in the central fixed cylinder (26) located in the mounting cylinder portion (211); the outer ring of the connecting bearing (27) is connected to the mounting cylinder portion (211), and the inner ring of the connecting bearing (27) is connected to the inner wall of the connecting groove; The installation cylinder (211) is connected to an external driving structure, so that the installation cylinder (211) rotates relative to the central fixed cylinder (26).

3. A micro powder dry magnetic separator for reducing eddy current heating according to claim 2, characterized in that: The magnetic conductive block (23) comprises silicon steel sheets (232), wherein the silicon steel sheets (232) are arranged in multiple groups and are stacked layer by layer; a nano-aluminum oxide insulating coating (233) is coated between the upper and lower silicon steel sheets (232), and the stacking direction is parallel to the axis of the central fixed cylinder (26).

4. A micro powder dry magnetic separator for reducing eddy current heating according to claim 2, characterized in that: The high resistance insulating material (24) is a silicon carbide ceramic-based composite material with a resistivity of >10^4 Ω·m. The difference between the thermal expansion coefficient of the high-resistance insulating material (24) and the thermal expansion coefficient of the magnetic conductive block (23) is less than 5%.

5. A micro powder dry magnetic separator for reducing eddy current heating according to claim 2, characterized in that: The magnetic system (22) comprises an upper arc plate (221), a first pressing plate (222) and a second pressing plate (223); the upper arc plate (221) is fixed upward on the central fixed cylinder (26); the first pressing plate (222) and the second pressing plate (223) are both pressed tightly on the upper and lower sides of the plurality of groups of magnetic conductive blocks (23), and the upper arc plate (221) and the first pressing plate (222) are connected via a connecting support plate (224); The two ends of the first pressing plate (222) and the second pressing plate (223) are connected.

6. A micro powder dry magnetic separator for reducing eddy current heating according to claim 5, characterized in that: The inclined guide plates (42) are arranged in multiple layers and are located on the output end of the vibrating feeder (41); and are inclined from top to bottom toward the feed pipe opening (11); The height of the raised flow guide ribs (43) is 3 to 5 mm, the inclined flow guide plates (42) are distributed in multiple layers, and the spacing between adjacent raised flow guide ribs (43) is 1.2 to 1.5 times the average particle size of the mineral material.

7. A micro powder dry magnetic separator for reducing eddy current heating according to claim 5, characterized in that: The raised flow-guiding ribs (43) comprise guide strips (431) and fork strips (432); the guide strips (431) are arranged obliquely along the surface of the inclined flow-guiding plate (42); and the fork strips (432) are arranged in multiple groups.

8. A micro powder dry magnetic separator for reducing eddy current heating according to claim 5, characterized in that: The feedback controller (62) dynamically adjusts the rotation speed according to the temperature data so that the eddy current loss power satisfies the formula: ； Wherein k is the material constant, B is the magnetic induction intensity, f is the current frequency, and δ is the width of the gap separating the magnetic conductive block (23).

9. A micro powder dry magnetic separator for reducing eddy current heating according to claim 5, characterized in that: A fixing frame (7) is installed on the magnetic separation main frame (1), and a laser particle size counter (71) is installed on the fixing frame (7); The inlet diameter expansion member (5) comprises two groups of symmetrically distributed material baffle plates (51), the top ends of the two groups of material baffle plates (51) are provided with hinge interfaces (52), and are installed in the magnetic separation main frame (1) via installation shafts; A bidirectional lead screw (53) is installed on the side of the feed pipe opening (11) facing away from the hinge joint (52), and fixing blocks (54) are provided at the middle and both ends of the bidirectional lead screw (53) and are fixed to the magnetic separation main frame (1); setting position bearings (55) are installed in the fixing blocks (54) at both ends and are connected to the ends of the bidirectional lead screw (53), and a protective cover (56) is installed at the bottom of the bidirectional lead screw (53); A sliding groove (57) is provided on the baffle plate (51), and a lower slider (58) is installed in the sliding groove (57). The lower slider (58) is restricted in the sliding groove (57) and an upper nut seat (59) is rotatably connected to the lower slider (58). The upper nut seat (59) moves on the bidirectional lead screw (53). A bevel gear box (510) is installed at the end of the bidirectional lead screw (53), and a switch reduction motor (511) is installed on the magnetic separation main frame (1) to connect them.

10. A method for using a micro powder dry magnetic separator for reducing eddy current heating, characterized in that: The following steps are involved: Step a. Start the rotating magnetic roller assembly (2), apply alternating current to the annular excitation coil (3) through the central fixed cylinder (26) and the guide cylinder (251) after modulation by an external power supply device, and generate a radial alternating magnetic field perpendicular to the surface of the magnetic roller; Initial state: The initial value of the magnetic induction intensity of the alternating magnetic field is 0.3-1.2T, the frequency is 50-150Hz, and the direction of the magnetic field is orthogonal to the direction of movement of the ore; Step b. The ore is transported to the surface of the magnetic roller by a vibrating feeder (41) and a multi-layer inclined guide plate (42). The raised guide ribs (43) of the inclined guide plate (42) disperse the ore in the axial direction of the magnetic roller to form a uniform material layer with a thickness fluctuation of ≤±1.5mm; the vibration frequency of the inclined guide plate (42) is 20 to 40Hz, the period of the raised guide ribs (43) is 1.5 to 2 times the average particle size of the ore, and the inclined guide plate (42) has an adjustable inclination range of 45° to 60°; Step c. Real-time monitoring of the surface temperature distribution of the magnetic roller. When the local temperature exceeds a set threshold, the feedback controller (62) simultaneously reduces the rotation speed of the magnetic roller and increases the excitation current frequency. The feedback controller (62) dynamically adjusts the rotation speed according to the temperature data so that the eddy current loss power satisfies the formula: Care needs to be taken to determine its critical maximum value; Step d. detecting the particle concentration in the distribution device (4) by means of a laser particle size counter (71); Step e. According to the detected concentration, the data is transmitted to the control cabinet for data analysis, and then the bevel gear box (510) is controlled by the switch reduction motor (511) to drive the bidirectional screw (53) to rotate, and the upper nut seats (59) on both sides of the bidirectional screw (53) move to both sides, driving the lower slider (58) to move outward, driving the two sets of hinged baffle plates (51) to rotate, thereby opening the communication area with the feed pipe opening (11), thereby controlling the feed speed; Step f, synchronously, an infrared sensor (61) is installed in the magnetic separation main frame (1) to detect the surface temperature of the separation cylinder (21), and the transmission speed of the installation cylinder (211) is controlled by the driving structure.

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