Iron ore grading device and method

Abstract

The invention provides an iron ore grading device and method, and relates to the technical field of mineral processing. The grading device comprises a feeding module, a receiving module, a primary screening module, a secondary sorting module and an intelligent control module. The primary screening module is used for at least separating out coarse-grained products, fine-grained products and middle-granularity materials with the granularity between the coarse-grained products and the fine-grained products from the iron ore raw materials; the secondary sorting module is used for sorting the materials with the middle granularity and comprises a sorting bin, a vibration screening unit and a composite force field sorting unit, the vibration screening unit and the composite force field sorting unit are arranged from top to bottom, and the composite force field sorting unit sorts out first-stage magnetic ore, second-stage magnetic ore and conductive gangue on the basis of a magnetoelectric coupling force field. On the basis, the internal cooperation relation among vibration, the magnetic field and the electric field can be used for efficiently and accurately sorting the middle-particle-size materials which are difficult to treat in the iron ore, and therefore the problem that the middle-particle-size iron ore cannot be efficiently classified in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, specifically to an iron ore grading device and method. Background Technology

[0002] Iron ore, as a fundamental raw material for the steel industry, is crucial for national energy security and sustainable development. Its efficient classification and sorting are key steps in improving resource utilization and reducing energy consumption in the steel industry. Currently, the classic process of crushing, screening, grinding, and magnetic separation / flotation is widely used for iron ore classification. However, in long-term practice, the problem of processing intermediate-sized iron ore with a particle size between 1 and 10 mm (the specific range can be slightly adjusted according to the ore properties) has remained unsolved, becoming a key bottleneck restricting the improvement of beneficiation efficiency and efficient resource recovery. Specifically: Intermediate-sized iron ore has unique material characteristics: insufficient liberation of individual particles, often containing a large amount of intergrowth of iron minerals and gangue; however, its particle size is significantly larger than the upper limit of conventional flotation processes (usually ≤0.15mm), making it difficult to directly enter high-energy-consuming grinding and flotation systems for deep separation; if conventional dry magnetic separation equipment is used, it can only perform coarse separation based on magnetic differences, and cannot identify the compositional differences within the intergrowth, resulting in concentrate grades that are usually below standard and do not meet smelting requirements; if it is returned to the ball mill for re-grinding, additional energy is required, and it is very easy to cause over-grinding, which in turn causes fine iron minerals to be lost with the tailings, further reducing the resource recovery rate. For example, patent CN118925927A provides a method for fine classification and pre-selection of weakly magnetic, difficult-to-separate iron ore. The method screens the iron ore into multiple particle sizes, such as 0-1mm, 1-6mm, and 6-15mm. The 1-6mm particle size is separated using a coarse wet strong magnetic separator, while the 6-15mm particle size is separated using a dry strong magnetic separator. Although this method achieves a certain degree of particle size subdivision, it does not optimize the material characteristics in the 6-10mm transition range. In this range, the proportion of intergrowths is relatively high. When using dry strong magnetic separation, the magnetic force can only act on the magnetic components in the intergrowths and cannot separate gangue impurities, resulting in a low concentrate grade in this particle size range.

[0003] In summary, existing technologies lack sufficient understanding of the characteristics of intermediate-grained iron ore and lack efficient separation technologies that take into account both magnetic and compositional differences, leading to persistent problems of resource waste and energy redundancy. Therefore, developing dedicated grading technologies for intermediate-grained iron ore to achieve precise separation of intercalated ore and efficient resource recovery has become an urgent technical need to be addressed in the mineral processing field. Summary of the Invention

[0004] The purpose of this invention is to provide an iron ore grading device and method to solve the problem mentioned in the background art that the prior art cannot efficiently grade intermediate-sized iron ore.

[0005] This invention is achieved using the following technical solution: An iron ore grading device includes a feeding module and a receiving module, as well as a primary screening module, a secondary sorting module, and an intelligent control module. The discharge port of the feeding module is connected to the inlet of the primary screening module. The primary screening module is used to separate iron ore raw materials into at least coarse-grained products (typically with a particle size >10mm), fine-grained products (typically with a particle size <1mm), and intermediate-grained materials with particle sizes between the two. The discharge port of the intermediate-grained materials of the primary screening module is connected to the inlet of the secondary sorting module. The secondary sorting module is used to sort the intermediate-grained materials and includes a sorting bin and a vibrating screening unit and a composite force field sorting unit arranged from top to bottom. The composite force field sorting unit separates primary magnetic ore (strongly magnetic concentrate), secondary magnetic ore (weakly magnetic middlings), and highly conductive gangue based on a magnetoelectric coupling force field. The intelligent control module is electrically connected to the vibrating screening unit and the composite force field sorting unit respectively, and is used to control the vibration rhythm of the vibrating screening unit and the force parameters of the composite force field sorting unit.

[0006] The iron ore grading device provided by this invention features a secondary sorting module designed after the primary screening module. This module utilizes the inherent synergistic relationship between vibration, magnetic field, and electric field to efficiently and accurately sort difficult-to-process intermediate-sized materials in iron ore. Specifically, the composite force field sorting unit, as the core of the secondary sorting module, acts on the material during its descent through a constructed magnetoelectric coupling force field. During this process, highly magnetic, low-conductivity particles (such as magnetite monomers) experience a much stronger magnetic force than the electric force, while weakly magnetic, medium-conductivity particles (such as iron-...) experience a much stronger electric force. The magnetic and electric forces experienced by gangue intergrowths are approximately equal. Non-magnetic, highly conductive particles (such as pyrite gangue) experience a much stronger electric force than the magnetic force. Therefore, the trajectory of primary magnetic ore (a strongly magnetic concentrate) will deviate towards the direction of the magnetic force, the trajectory of highly conductive gangue will deviate towards the direction of the electric force, and the trajectory of secondary magnetic ore (a weakly magnetic intermediate ore) will be between that of primary magnetic ore and highly conductive gangue. By achieving these three types of particle trajectory deviations, and coordinating with the separate collection of these three types in the receiving module, the sorting of intermediate particle sizes can be effectively completed. The vibrating screen unit, located above the composite force field sorting unit, creates an optimal initial state for the material entering the force field, helping to improve the sorting effect.

[0007] Furthermore, the composite force field sorting unit includes an asymmetric magnetic field system and an electrostatic field system. The asymmetric magnetic field system includes a pair of vertically arranged pole shoes, a magnetic yoke body connected between the two pole shoes, and an excitation coil wound around the magnetic yoke body. The magnetic yoke body is vertically arranged outside the sorting chamber, and the working surfaces of the two pole shoes extend into one side of the sorting chamber. The two pole shoes are a blunt pole located above and a sharp pole located below, respectively. The blunt pole and the sharp pole are used to form an asymmetric vertical magnetic field region with a weak upper and strong lower magnetic field in one side of the sorting chamber. The electrostatic field system includes a vertically arranged high-voltage electrode plate located in the other side of the sorting chamber, opposite to the asymmetric magnetic field system, to form a vertical electrostatic field region. The asymmetric vertical magnetic field region is used to sort primary magnetic ores, the vertical electrostatic field region is used to sort conductive gangue, and the region between the asymmetric vertical magnetic field region and the vertical electrostatic field region is used to sort secondary magnetic ores.

[0008] In the above structure, the asymmetric magnetic field system and electrostatic field system located on both sides constitute a magnetoelectric coupling force field, where the magnetic field and electric field each exert their effectiveness in independent spatial regions. In the asymmetric magnetic field system, the magnetic field strength is not uniformly distributed; the strongest magnetic field is concentrated in a small area near the sharp pole, and the magnetic field strength decreases rapidly from the sharp pole outward (including towards the blunt pole), thus forming an asymmetric vertical magnetic field region. This asymmetric vertical magnetic field region forms a high-intensity, high-gradient magnetic field band on one side of the sorting chamber, which forces different magnetic particles to produce significant differences in horizontal trajectory during their fall. The electrostatic force and magnetic field force have different ranges and properties. The high magnetic field gradient generated by the sharp pole is a short-range force. For most of the space inside the sorting chamber, including the center and the other side, the influence of the magnetic field from the sharp pole is greatly reduced. Therefore, the high-voltage electrode plate mainly operates in a relatively weak background magnetic field, thus avoiding mutual interference between the electrostatic field and the gradient magnetic field.

[0009] Furthermore, the working surfaces of both the blunt and sharp electrodes are vertically arranged facing the center of the sorting chamber. The working surface of the blunt electrode is a smooth surface, while the working surface of the sharp electrode is provided with a protruding structure for concentrating magnetic lines of force.

[0010] In the above structure, the working surface of the blunt pole has no protrusions and its function is to conduct magnetic fields and form a weak magnetic field region. The protrusions (serrations, spikes, or matrices) on the working surface of the sharp pole are the core of its high performance. The principle is the magnetic flux concentration effect. That is, when the magnetic flux passes from the blunt pole through the sorting bin to the sharp pole, it will be forced to concentrate at the tip of these protrusions, which will cause the magnetic flux density and magnetic field gradient at the tip to increase sharply, thereby generating a magnetic force much higher than that of the blunt pole.

[0011] Furthermore, the secondary sorting module also includes an airflow coordination unit, which includes an airflow nozzle array arranged circumferentially along the inner sidewall of the sorting chamber. The airflow nozzle array includes several airflow nozzles, and the spraying directions of the several airflow nozzles are respectively directed towards the sharp pole in the asymmetric magnetic field system and the high-voltage electrode plate in the electrostatic field system.

[0012] In the above structure, the airflow coordination unit can coordinate and enhance the trajectory deviation of particles. Specifically, the directional airflow ejected from the airflow nozzle can provide directional boost to the movement of particles, thereby amplifying the trajectory deviation caused by the magnetic field and electrostatic field, thus enhancing the separation effect, preventing particle mixing, and ensuring the purity of the sorted products.

[0013] Furthermore, the intelligent control module is electrically connected to the excitation coil and high-voltage electrode plate in the composite force field unit, and is configured to control the vibration rhythm of the vibrating screening unit to couple with the magnetic field change period of the asymmetric magnetic field system, and to adjust the working frequency of the asymmetric magnetic field system in conjunction with the working voltage of the electrostatic field system.

[0014] In the above structure, the intelligent control module can achieve vibration and magnetic field timing coupling and magnetoelectric frequency linkage during the sorting process. Specifically, by controlling the vibration rhythm of the vibrating screening unit and the magnetic field change cycle of the asymmetric magnetic field system, the changing magnetic field force can be applied precisely when the material is thrown up and in a loose state. This can more effectively cause the intergrowth particles to separate at the interface and ensure that the particles that have just fallen into the composite force field correspond to the high magnetic field force. When the working frequency of the asymmetric magnetic field system is adjusted in linkage with the working voltage of the electrostatic field system, the magnetic field working frequency is automatically reduced when the electrostatic field voltage increases. This reduces the sensitivity of the system under high electric field strength, thereby further improving operational stability.

[0015] Furthermore, an electromagnetic shielding layer is provided in the internal space of the sorting chamber wall between the high-voltage electrode plate and the asymmetric magnetic field system, which is isolated from the sorting space inside the sorting chamber.

[0016] In the above structure, the electromagnetic shielding layer is embedded inside the structural wall of the sorting chamber. It does not contact the electrode plate or the magnetic yoke, but maintains a certain insulating distance from both. Therefore, it can achieve physical isolation between the magnetic field and the force field without being exposed inside the sorting chamber or affecting the normal sorting of materials. This confines the high-voltage electrostatic field generated by the high-voltage electrode plate to the electrostatic field region, while significantly attenuating the electromagnetic interference of the pulsating magnetic field of the magnetic field system on the high-voltage electrode plate, thereby ensuring the internal independence and stability of the magnetoelectric composite force field.

[0017] Furthermore, the outer wall of the sorting chamber is provided with at least two transparent observation windows circumferentially, and the opening positions of the at least two transparent observation windows correspond to the asymmetric vertical magnetic field region and the vertical electrostatic field region, respectively; a visual detection component is provided on the outer side of each transparent observation window, and the visual detection component is electrically connected to the intelligent control unit.

[0018] In the above structure, the movement trajectory image of the particle group can be captured in real time through the transparent observation window and visual detection components. Then, the intelligent control module can use image processing algorithms to identify areas with mixed trajectories and unclear separation, and then adjust the working parameters of the secondary sorting module accordingly based on the identification results. This is equivalent to configuring a real-time correction system for the sorting process, which can adaptively compensate for the attenuation of sorting performance caused by feeding fluctuations or changes in equipment status.

[0019] Furthermore, the receiving module includes at least a coarse-grained product receiving bin, a fine-grained product receiving bin, a primary magnetic ore receiving bin, a secondary magnetic ore receiving bin, and a conductive gangue receiving bin; the coarse-grained product receiving bin is connected to the coarse-grained product outlet of the primary screening module, and the fine-grained product receiving bin is connected to the fine-grained product outlet of the primary screening module; the primary magnetic ore receiving bin, the secondary magnetic ore receiving bin, and the conductive gangue receiving bin are all located below the sorting bin, and correspond to the primary magnetic ore outlet, the secondary magnetic ore outlet, and the conductive gangue outlet respectively opened at the bottom of the sorting bin.

[0020] A method for classifying iron ore, using the iron ore classification device described above, includes the following steps: Step 1: After feeding, perform one screening. Through a single screening module, iron ore raw materials are screened into at least coarse-grained products, fine-grained products, and intermediate-grained materials with particle sizes between the two. Step 2: Perform secondary sorting on intermediate particle size materials; Intermediate particle size material is introduced into the secondary sorting module. The intermediate particle size material is then fed into the composite force field sorting unit through the vibrating screening unit. Based on the magnetoelectric coupling force field in the composite force field sorting unit, the intermediate particle size material is screened into primary magnetic ore that deviates towards the magnetic field direction, secondary magnetic ore located in the region between the magnetic field and the electric field, and conductive gangue that deviates towards the electric field direction. Step 3: Product and material collection; The coarse-grained product, fine-grained product, primary magnetic ore, secondary magnetic ore, and conductive gangue are collected separately through the corresponding receiving bins.

[0021] Furthermore, in step 2, the intelligent control module performs the following operations: a. Control the vibration rhythm of the vibrating screening unit to couple it with the magnetic field change cycle so that intermediate particle size material enters the composite force field sorting unit when the magnetic field force is in a specific phase; b. Adjust the working frequency of the magnetic field in conjunction with the working voltage of the electric field.

[0022] The beneficial effects achieved by this invention are: This invention provides an iron ore grading device and method. By setting up a primary screening module, a secondary separation module, and an intelligent control module, and limiting the grading steps based on these modules, it can separate primary magnetic ore, secondary magnetic ore, and conductive gangue under the synergistic effect of multiple physical fields including vibration, magnetic field, and electric field. Based on this, compared with existing technologies that can only use conventional dry magnetic separation equipment or return the ore to a ball mill for regrinding, this invention innovatively achieves efficient separation of intermediate-sized iron ore materials through a magnetoelectric coupling force field, thereby effectively solving the industry problem of low separation efficiency and large resource waste in intermediate-sized intergrowths. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the grading device described in an embodiment of the present invention; Figure 2 This is a vertical cross-sectional view of the structural composition of the secondary sorting module in the grading device described in this embodiment of the invention; Figure 3 This is a cross-sectional schematic diagram of the structural composition of the composite force field sorting unit in the grading device described in this embodiment of the invention; Figure 4 This is a block diagram of the collaborative control logic of the intelligent control module in the grading device described in this embodiment of the invention; Figure 5 This is a schematic diagram of the process steps of the grading method described in the embodiment of the present invention; In the diagram: 1. Hopper; 2. Feeder; 3. Upper screen; 4. Coarse-grained product receiving bin; 5. Lower screen; 6. Fine-grained product receiving bin; 7. Primary magnetic ore receiving bin; 8. Secondary magnetic ore receiving bin; 9. Conductive gangue receiving bin; 10. Secondary sorting module; 11. Intelligent control module; 12. Screen body; 13. Passive pole; 14. Magnetic yoke body; 15. Excitation coil; 16. Sharp pole; 17. Electrode plate; 18. Airflow nozzle; 19. Sorting bin. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0025] Example 1 The first aspect of this embodiment provides an iron ore grading device. Please refer to... Figures 1 to 4It includes a feeding module, a primary screening module, a secondary sorting module 10, a receiving module, and an intelligent control module 11, specifically: The feeding module is used to transport iron ore raw materials to the primary screening module. The feeding module includes a hopper 1 and a feeder 2. The feed inlet of the feeder 2 is connected to the discharge outlet of the hopper 1, and the discharge outlet of the feeder 2 is connected to the feed inlet of the primary screening module.

[0026] The primary screening module is used to separate iron ore raw materials into coarse-grained products with a particle size >10mm, fine-grained products with a particle size <1mm, and intermediate-grained materials with a particle size between 1mm and 10mm. The primary screening module is a rectangular vibrating screen box with two layers of inclined vibrating screens distributed vertically inside the box. The upper screen 3 uses a 10mm aperture to intercept coarse-grained products, and the lower screen 5 uses a 1mm aperture to intercept intermediate-grained materials and separate fine-grained products. The outer wall of the box has three discharge ports, which are respectively connected to a coarse-grained product receiving bin 4 for receiving coarse-grained products, a fine-grained product receiving bin 6 for receiving fine-grained products, and a connecting chute (with a polytetrafluoroethylene lining to reduce material adhesion) for conveying intermediate-grained materials. The discharge port of the connecting chute is connected to the inlet of the secondary sorting module 10.

[0027] The secondary sorting module 10 is used to sort intermediate-sized materials, and can separate primary magnetic ore (strongly magnetic concentrate), secondary magnetic ore (weakly magnetic middlings), and highly conductive gangue based on a magnetoelectric coupling force field. The secondary sorting module 10 includes a vertically arranged cylindrical sorting bin 19, and a vibrating screening unit and a composite force field sorting unit arranged from top to bottom, wherein: The vibrating screening unit is located at the upper part of the sorting chamber 19 and is used to break up agglomerates of intermediate-sized materials. It includes a screen body 12 and an electromagnetic vibrator. The diameter of the screen body 12 is adapted to the inner diameter of the sorting chamber 19, the aperture is 5mm~8mm, the material is wear-resistant stainless steel, and the surface is coated with polytetrafluoroethylene. The output end of the electromagnetic vibrator is connected to the screen body 12 and is used to drive the screen body 12 to vibrate.

[0028] The composite force field sorting unit is located below the screen body 12 and includes an asymmetric magnetic field system and an electrostatic field system, wherein: The asymmetric magnetic field system includes a pair of vertically arranged pole shoes, a "["-shaped magnetic yoke body 14 connected between the two pole shoes, and an excitation coil 15 wound on the magnetic yoke body 14. The magnetic yoke body 14 is vertically arranged on the outside of the sorting chamber 19, and the working surfaces of the two pole shoes extend into one side of the sorting chamber 19. The two pole shoes are a blunt pole 13 located above and a sharp pole 16 located below. Both the blunt pole 13 and the sharp pole 16 are arc-shaped plates (matching the arc shape of the inner wall of the sorting chamber 19). The working surfaces of the blunt pole 13 and the sharp pole 16 are vertically arranged facing the center of the sorting chamber 19. The working surface of the blunt pole 13 is a smooth surface, and the working surface of the sharp pole 16 is provided with a tooth-shaped array of protrusions for concentrating magnetic lines of force. Based on this, the blunt pole 13 and the sharp pole 16 can form an asymmetric vertical magnetic field region with a weak upper and strong lower region in one side of the sorting chamber 19.

[0029] The electrostatic field system includes a vertically arranged high-voltage electrode plate 17 located on the opposite side of the sorting chamber 19, opposite to the asymmetric magnetic field system. This plate forms a vertical electrostatic field region, with the electric force directed from the center of the sorting chamber 19 towards the electrode plate 17. The vertical height of the high-voltage electrode plate 17 completely covers the region from the blunt electrode 13 to the sharp electrode 16, ensuring that the range of the electric field and the magnetic field are vertically aligned. However, because the magnetic field of the sharp electrode 16 is short-range, the electrode plate 17 is only exposed to a weak background magnetic field and is free from magnetic interference. An electromagnetic shielding layer (not shown in the figure) made of a highly conductive non-magnetic material is installed inside the wall of the sorting chamber 19 between the high-voltage electrode plate 17 and the asymmetric magnetic field system. This electromagnetic shielding layer is isolated from the sorting space inside the sorting chamber 19 and reliably grounded via a low-impedance wire.

[0030] In this embodiment, the secondary sorting module 10 further includes an airflow coordination unit, which includes an array of airflow nozzles 18 arranged circumferentially along the inner sidewall of the sorting chamber 19. The airflow nozzle array includes twelve airflow nozzles 18 that are pulsed and sprayed by high-speed solenoid valves. The twelve airflow nozzles 18 are divided into three groups of four. The three groups of airflow nozzles 18 are arranged at different heights. The spray direction of two airflow nozzles 18 in each group is directed towards the sharp pole 16 in the asymmetric magnetic field system, and the spray direction of the other two airflow nozzles 18 is directed towards the high voltage electrode plate 17 in the electrostatic field system.

[0031] Furthermore, at least two transparent observation windows (not shown in the figure) are arranged circumferentially on the outer wall of the sorting chamber 19. The opening positions of the at least two transparent observation windows correspond to the asymmetric vertical magnetic field region and the vertical electrostatic field region, respectively. A visual detection component is provided on the outer side of each transparent observation window, and the visual detection component is electrically connected to the intelligent control unit.

[0032] In addition, a sharp-electrode cleaning component and an electrode plate anti-adsorption component can be set in the composite force field separation unit. The sharp-electrode cleaning component is located above the sharp-electrode 16 tooth tip and includes several high-pressure air flushing nozzles, which can evenly blow the strongly magnetic concentrate adsorbed by the sharp-electrode 16 tooth tip to the bottom discharge port of the separation chamber 19 to avoid excessive adsorption or uneven shedding. The electrode plate anti-adsorption component includes several high-frequency micro-vibrators installed on the surface of the high-voltage electrode plate 17, which can vibrate in real time to prevent highly conductive gangue from adsorbing on the surface of the high-voltage electrode plate 17.

[0033] The receiving module includes a coarse-grained product receiving bin 4, a fine-grained product receiving bin 6, a primary magnetic ore receiving bin 7, a secondary magnetic ore receiving bin 8, and a conductive gangue receiving bin 9. The coarse-grained product receiving bin 4 is connected to the outlet of the primary screening module for coarse-grained products, and the fine-grained product receiving bin 6 is connected to the outlet of the primary screening module for fine-grained products. The primary magnetic ore receiving bin 7, the secondary magnetic ore receiving bin 8, and the conductive gangue receiving bin 9 are all located below the sorting bin 19 and correspond to the primary magnetic ore outlet, secondary magnetic ore outlet, and conductive gangue outlet at the bottom of the sorting bin 19, respectively. In this embodiment, a multi-degree-of-freedom product diverter is also connected at the bottom outlet of the sorting bin 19. This diverter has multiple guide plates whose horizontal orientation and tilt angle can be independently adjusted. Each guide plate is driven by a stepper motor to rotate and extend, etc., to precisely guide particles with different motion trajectories into the corresponding collection bins.

[0034] The intelligent control module 11 is a rectangular cabinet that is electrically connected to the electromagnetic vibrator in the vibrating screening unit, the excitation coil 15 and high-voltage electrode plate 17 in the composite force field sorting unit, the high-speed solenoid valve in the airflow coordination unit, the vision detection component, and the stepper motor of the diverter. Based on this, the intelligent control module 11 is used to control the vibration rhythm of the vibrating screening unit, adjust the force parameters of the composite force field sorting unit, adjust the airflow injection parameters, perform visual recognition analysis, and adjust the tilt angle of the diverter guide plate.

[0035] The second aspect of this embodiment provides an iron ore grading method, which applies the iron ore grading device described above. Please refer to [reference needed]. Figure 5 It includes the following steps: Step 1: After feeding, perform one screening. Iron ore raw materials are fed into the primary screening module through hopper 1 and feeder 2. The two layers of vibrating screens can sequentially screen the iron ore raw materials into coarse-grained products, fine-grained products, and intermediate-grained materials with particle sizes between the two. The coarse-grained products fall into the coarse-grained product receiving bin 4, the fine-grained products fall into the fine-grained product receiving bin 6, and the intermediate-grained materials fall into the connecting chute.

[0036] Step 2: Perform secondary sorting on intermediate particle size materials; Intermediate-sized materials enter the secondary sorting module 10 via a connecting chute. An electromagnetic vibrator in the vibrating screening unit drives the screen body 12 to vibrate, causing the agglomerated materials to break up and fall into the composite force field sorting unit. Based on the magnetoelectric coupling force field in the composite force field sorting unit, the intermediate-sized materials are screened into primary magnetic ores shifted towards the magnetic field direction, secondary magnetic ores located in the region between the magnetic and electric fields, and conductive gangue shifted towards the electric field direction. Specifically: After passing through the screen body 12, intermediate-sized materials fall freely under gravity. During this fall: primary magnetic ore is subjected to a strong magnetic gradient force at the tip of the sharp electrode 16, causing its trajectory to rapidly shift towards the sharp electrode 16; the airflow nozzle 18 corresponding to the sharp electrode 16 sprays in a pulsed manner synchronized with the magnetic field, giving the particles additional momentum and ensuring their shift. Highly conductive gangue is almost unaffected by the magnetic field, but is pulled by the electrostatic force of the high-voltage electrode plate 17, causing its trajectory to shift towards the high-voltage electrode plate 17; the airflow nozzle 18 corresponding to the high-voltage electrode plate 17 sprays synchronously, assisting the high-conductivity gangue in shifting its trajectory. Secondary magnetic ore is not subjected to a dominant magnetic or electric force, so it falls in the region between the magnetic and electric fields, experiencing only a slight shift.

[0037] In this step, the intelligent control module 11 performs the following operations: a. Control the vibration rhythm of the vibrating screening unit to couple it with the magnetic field change cycle, so that intermediate particle size material enters the composite force field sorting unit when the magnetic field force is in a specific phase.

[0038] b. Adjust the working frequency of the magnetic field in conjunction with the working voltage of the electric field; for example, when the working voltage of the high voltage electrode plate 17 rises to the first preset threshold, automatically switch the working frequency of the magnetic field from the first frequency range to the second frequency range, wherein the upper limit of the second frequency range is lower than that of the first frequency range.

[0039] c. Control the operation of the airflow nozzle 18 to synchronize the airflow pulse with the magnetic field change cycle; d. Based on the particle trajectory image captured by the vision detection component, the working parameters of the airflow nozzle 18, magnetic field, and electric field are adjusted accordingly; for example, if the adsorption rate of strongly magnetic particles decreases, the magnetic field strength can be increased and the jet speed of the airflow nozzle 18 on the sharp pole 16 side can be increased.

[0040] Step 3: Product and material collection; The diverter guides the primary magnetic ore, secondary magnetic ore, and conductive gangue to their respective receiving bins, thus completing the separate collection of different particles.

[0041] It should be noted that the parts of the above solutions that are not described in detail or in an elaborate manner are all prior art, and are not improvements made by this invention to the prior art, nor are they within the protection scope of the technical solutions of this invention. Therefore, they will not be elaborated on in this article.

[0042] Of course, the above description is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the embodiments of the present invention. The present invention is also not limited to the above examples, and all equivalent changes and improvements made by those skilled in the art within the scope of the present invention should fall within the patent coverage of the present invention.

Claims

1. An iron ore grading device, comprising a feeding module and a receiving module, characterized in that: It also includes a primary screening module, a secondary sorting module (10), and an intelligent control module (11); The discharge port of the feeding module is connected to the feed port of the primary screening module. The primary screening module is used to separate iron ore raw materials into at least coarse-grained products, fine-grained products, and intermediate-grained materials with particle sizes between the two, wherein the particle size of the coarse-grained products is larger than that of the fine-grained products. The discharge port of the intermediate particle size material of the primary screening module is connected to the feed port of the secondary sorting module (10). The secondary sorting module (10) is used to sort the intermediate particle size material, including a sorting bin (19) and a vibrating screening unit and a composite force field sorting unit arranged from top to bottom. The composite force field sorting unit sorts out primary magnetic ore, secondary magnetic ore and conductive gangue based on the magnetoelectric coupling force field. The intelligent control module (11) is electrically connected to the vibrating screening unit and the composite force field sorting unit respectively, and is used to control the vibration rhythm of the vibrating screening unit and the force parameters of the composite force field sorting unit.

2. The iron ore grading device according to claim 1, characterized in that: The composite force field sorting unit includes an asymmetric magnetic field system and an electrostatic field system; The asymmetric magnetic field system includes a pair of vertically arranged pole shoes, a magnetic yoke body (14) connected between the two pole shoes, and an excitation coil (15) wound on the magnetic yoke body (14); the magnetic yoke body (14) is vertically arranged outside the sorting chamber (19), and the working surfaces of the two pole shoes extend into one side region inside the sorting chamber (19); the two pole shoes are a blunt pole (13) located above and a sharp pole (16) located below, respectively, and the blunt pole (13) and sharp pole (16) are used to form an asymmetric vertical magnetic field region with a weak upper and strong lower magnetic field in one side region inside the sorting chamber (19); The electrostatic field system includes vertically arranged electrode plates (17), which are located in the opposite region inside the sorting bin (19) to the asymmetric magnetic field system, for forming a vertical electrostatic field region. The asymmetric vertical magnetic field region is used to separate primary magnetic ores, the vertical electrostatic field region is used to separate conductive gangue, and the area between the asymmetric vertical magnetic field region and the vertical electrostatic field region is used to separate secondary magnetic ores.

3. The iron ore grading device according to claim 2, characterized in that: The working surfaces of the blunt electrode (13) and the sharp electrode (16) are both vertically arranged facing the center of the sorting chamber (19). The working surface of the blunt electrode (13) is a smooth surface, and the working surface of the sharp electrode (16) is provided with a protruding structure for gathering magnetic lines of force.

4. The iron ore grading device according to claim 2, characterized in that: The secondary sorting module (10) further includes an airflow coordination unit, which includes an array of airflow nozzles (18) arranged circumferentially along the inner sidewall of the sorting chamber (19). The airflow nozzle (18) array includes several airflow nozzles (18), and the spraying directions of the several airflow nozzles (18) are respectively directed towards the sharp pole (16) in the asymmetric magnetic field system and the electrode plate (17) in the electrostatic field system.

5. The iron ore grading device according to claim 2, characterized in that: The intelligent control module (11) is electrically connected to the excitation coil (15) and electrode plate (17) in the composite force field unit, and is configured to control the vibration rhythm of the vibrating screening unit to couple with the magnetic field change period of the asymmetric magnetic field system, and to adjust the working frequency of the asymmetric magnetic field system in conjunction with the working voltage of the electrostatic field system.

6. The iron ore grading device according to claim 2, characterized in that: An electromagnetic shielding layer is provided in the internal space of the sorting chamber (19) between the electrode plate (17) and the asymmetric magnetic field system. This electromagnetic shielding layer is isolated from the sorting space inside the sorting chamber (19).

7. The iron ore grading device according to claim 2, characterized in that: The outer wall of the sorting chamber (19) is provided with at least two transparent observation windows in the circumferential direction. The opening positions of the at least two transparent observation windows correspond to the asymmetric vertical magnetic field region and the vertical electrostatic field region, respectively. A visual detection component is provided on the outside of each transparent observation window, and the visual detection component is electrically connected to the intelligent control unit.

8. The iron ore grading device according to claim 2, characterized in that: The receiving module includes at least a coarse-grained product receiving bin (4), a fine-grained product receiving bin (6), a primary magnetic ore receiving bin (7), a secondary magnetic ore receiving bin (8), and a conductive gangue receiving bin (9). The coarse-grained product receiving bin (4) is connected to the coarse-grained product outlet of the primary screening module, and the fine-grained product receiving bin (6) is connected to the fine-grained product outlet of the primary screening module. The primary magnetic ore receiving bin (7), the secondary magnetic ore receiving bin (8), and the conductive gangue receiving bin (9) are all located below the sorting bin (19), and correspond to the primary magnetic ore outlet, the secondary magnetic ore outlet, and the conductive gangue outlet opened at the bottom of the sorting bin (19), respectively.

9. A method for classifying iron ore, using the iron ore classification apparatus according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: After feeding, perform one screening. Through a single screening module, iron ore raw materials are screened into at least coarse-grained products, fine-grained products, and intermediate-grained materials with particle sizes between the two. Step 2: Perform secondary sorting on intermediate particle size materials; The intermediate particle size material is introduced into the secondary sorting module (10), and the intermediate particle size material is sent to the composite force field sorting unit through the vibrating screening unit. Based on the magnetoelectric coupling force field in the composite force field sorting unit, the intermediate particle size material is screened into primary magnetic ore that deviates towards the magnetic field direction, secondary magnetic ore located in the region between the magnetic field and the electric field, and conductive gangue that deviates towards the electric field direction. Step 3: Product and material collection; The coarse-grained product, fine-grained product, primary magnetic ore, secondary magnetic ore, and conductive gangue are collected separately through the corresponding receiving bins.

10. The iron ore grading method according to claim 9, characterized in that, In step 2, the intelligent control module (11) performs the following operations: a. Control the vibration rhythm of the vibrating screening unit to couple it with the magnetic field change cycle so that intermediate particle size material enters the composite force field sorting unit when the magnetic field force is in a specific phase; b. Adjust the working frequency of the magnetic field in conjunction with the working voltage of the electric field.

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