A nondestructive off-line cleaning method for a strong magnetic machine medium box

Abstract

The present application relates to the technical field of ore dressing equipment maintenance, and particularly relates to a nondestructive offline cleaning method for a strong magnetic machine medium box, comprising the following steps: S1: disassembly pretreatment, S2: critical temperature interface embrittlement drying, S3: uniform inertial force nondestructive desliming, S4: self-cleaning effect low-pressure spraying, and S5: performance inspection. Through the above steps, the traditional idea of strong impact force cleaning is abandoned, and the critical temperature interface embrittlement and uniform inertial force stripping are adopted, so that the whole process is free of mechanical knocking, high-temperature damage and chemical corrosion. The three-step synergistic process can completely remove the hardened clay and blocked coarse particles in the gap of the tooth plate, and the permeability of the tooth plate gap of the cleaned medium box is restored to 100%, and the magnetic permeability is completely consistent with that of a new medium box.

Description

Technical Field

[0001] This invention relates to the field of mineral processing equipment maintenance technology, specifically to a non-destructive offline cleaning method for a strong magnetic medium box. Background Technology

[0002] In the beneficiation of weakly magnetic minerals such as ilmenite, the vertical pulsed high-gradient magnetic separator is the core equipment for ilmenite separation and recovery. Its internal media box is the key functional component for mineral separation. The media box contains multiple layers of magnetically conductive toothed plates. These plates generate a high-gradient induced magnetic field in the background magnetic field, thereby precisely adsorbing weakly magnetic ilmenite particles in the slurry and achieving the separation of ilmenite from gangue minerals.

[0003] During long-term continuous production, clay minerals (mainly kaolinite and montmorillonite) and coarse non-magnetic gangue particles in the slurry are prone to clogging and agglomerating in the gaps of the magnetic guide plates in the media box. This causes blockage of the media box flow channels and a decrease in magnetic permeability, directly leading to reduced separation efficiency of the high-intensity magnetic separator and a decline in ilmenite recovery rate. In severe cases, it can even cause production accidents such as excessive equipment load and shutdown of the main unit. Therefore, the media box of the high-intensity magnetic separator needs to be cleaned online regularly. When the blockage is severe and online cleaning fails, the machine must be stopped and disassembled for offline deep cleaning.

[0004] Currently, the industry is conducting in-depth research on cleaning technology for high-powered magnetic media boxes. However, during the cleaning process, the fundamental technical contradiction of "the incompatibility between thorough cleaning and non-destructive cleaning of the media box" has not been overcome, and three deep-rooted technical biases have emerged: Bias 1: Deep blockages can only be cleared by strong external force. It is generally believed in the industry that the sludge deep within the gaps of the toothed plates has extremely strong binding force, and can only be broken and extruded by strong impact methods such as manual hammering or direct water jetting with pressure of 20MPa or more. This directly leads to irreversible damage such as deformation of the toothed plates of the media box, cracking of welds, and erosion of the substrate. The damage rate of media boxes cleaned manually is as high as 5% or more.

[0005] Bias 2: Drying is merely an auxiliary process to facilitate subsequent processing. In existing technologies, drying is only considered a means of "shortening natural air drying time," and no one has ever realized the precise critical matching relationship between drying temperature and the bonding force of the sludge interface and the thermal damage to the media box. The industry generally adopts the extensive mode of "the higher the temperature, the faster the drying," which either results in insufficient drying leading to difficulties in subsequent cleaning, or excessively high temperatures damaging the magnetic properties of the media box.

[0006] Bias 3: Non-destructive cleaning inevitably comes at the cost of efficiency and effectiveness. The industry generally believes that mild cleaning methods (such as low-pressure water and ultrasonic cleaning) can only handle minor blockages and cannot deal with severe caking; to achieve efficient batch cleaning, a certain degree of media cartridge wear must be accepted. This results in large concentrators in annual media cartridge replacement costs exceeding one million yuan, while also facing enormous safety and environmental pressures.

[0007] Based on the aforementioned technological biases, existing cleaning solutions suffer from the following four fundamental problems that cannot be solved: 1. Online cleaning: It can only handle slight adhering sludge on the surface of the toothed plate, and is completely ineffective for deep and stubborn blockages caused by clay compaction and coarse particles.

[0008] 2. Manual offline cleaning: Natural air drying cycle is 3-7 days, which is extremely labor-intensive, has a high damage rate to media boxes, and causes serious dust pollution.

[0009] 3. High-temperature baking + high-pressure water flushing: High temperatures above 400℃ irreversibly damage the magnetic properties of the magnetic tooth plate, and high-pressure water flushing causes erosion and deformation of the tooth plate, shortening the service life of the medium box by more than 60%.

[0010] 4. Pickling / Ultrasonic cleaning: Pickling corrodes the substrate and welds, generating hazardous waste; Ultrasonic cleaning can only handle minor blockages and cannot be used for batch operations.

[0011] In summary, existing technologies have consistently failed to break free from the traditional approach of "using strong external force to destroy blockages," and cannot simultaneously meet the core requirements of the ilmenite beneficiation industry for "high efficiency, non-destructive processing, batch processing, and safety and environmental protection" in media box cleaning. Summary of the Invention

[0012] The purpose of this invention is to provide a non-destructive offline cleaning method for a strong magnetic medium cartridge, so as to solve the problems pointed out in the background art.

[0013] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A non-destructive offline cleaning method for the media cartridge of a high-intensity magnetic concentrator, applicable to the offline cleaning of clogged media cartridges in vertical pulsating high-gradient high-intensity magnetic concentrators used for ilmenite beneficiation, characterized by comprising the following steps: S1: Disassembly and pretreatment: Remove the clogged media box to be cleaned from the main unit of the high-intensity magnet generator, remove the loose minerals and large debris from the surface of the media box, and obtain the media box to be cleaned; S2: Critical Temperature Interface Embrittlement Drying: Place the medium box to be cleaned into a hot air circulating drying oven, set the drying parameters of the hot air circulating drying oven to dry the medium box, so that the blockage sludge in the gap of the magnetic tooth plate of the medium box undergoes complete removal of interlayer water and irreversible lattice shrinkage, and uniform microcracks are formed at the interface between the sludge and the tooth plate. The sludge as a whole forms embrittled sludge in a brittle and fragmented state, and the dried medium box is obtained. S3: Uniform inertial force non-destructive desliming: The dried media box is locked and fixed on the vibration platform by clamps; after setting the vibration parameters optimized by modal test and finite element analysis, the vibration device is started. The vibration parameters match the interface peeling energy between the embrittled sludge and the toothed plate, and the vibration energy is lower than the structural fatigue threshold of the media box, and the vibration frequency is lower than the first natural frequency of the media box, so that the embrittled sludge is peeled off as a whole under the action of uniform inertial force. S4: Self-cleaning effect low-pressure spray: Transfer the media box after vibration desliming to the closed rinsing station, set the cleaning parameters and use clean water to spray the media box from the top, left and right sides to remove the residual dust and sludge on the media box, and obtain a clean media box. S5: Performance Inspection: The clean media cartridges are inspected for appearance, dimensional accuracy, and magnetic permeability. Media cartridges that pass the inspection are directly installed and used. Media cartridges that fail the inspection are cleaned again by repeating steps S2-S4.

[0014] A further technical solution is that the drying parameters include a drying time of 3h-9h and a drying temperature of 180℃-198℃, so that the drying temperature is precisely controlled below the thermal damage threshold of 200℃ for the magnetic tooth plate, and the temperature control accuracy is ±2℃, and the temperature uniformity deviation inside the chamber is ≤±5℃.

[0015] A further technical solution is that, in step S2, the moisture content of the sludge in the gap between the toothed plates of the media box to be cleaned is determined by the drying weight method; when the moisture content of the sludge is >15%, it is classified as a severely clogged media box, and the drying time is set to 7h-9h; when the moisture content of the sludge is ≤15%, it is classified as a lightly clogged media box, and the drying time is set to 3h-5h; after drying, the moisture content of the sludge in the gap between the media box to be cleaned is ≤3%.

[0016] A further technical solution is that the vibration parameters include a vibration frequency of 25 Hz-50 Hz, an amplitude of 1 mm-3 mm, and a vibration time of 3 min-5 min.

[0017] A further technical solution is that, in step S3, when the media box to be cleaned is a heavily clogged media box, the vibration frequency is set to 40 Hz-50 Hz, the amplitude is 2mm-3mm, and the vibration time is 4min-5min; when the media box to be cleaned is a lightly clogged media box, the vibration frequency is set to 25 Hz-35 Hz, the amplitude is 1mm-2mm, and the vibration time is 3min-4min.

[0018] A further technical solution is that the first-order natural frequency in step S3 is determined by a combination of hammer impact modal testing and finite element simulation verification.

[0019] A further technical solution is that, in step S3, the uniform inertial force non-destructive desliming process is carried out inside a sealed dust collection hood, and the mineral dust generated by vibration is collected and treated by a bag filter under negative pressure to ensure that the dust collection efficiency is ≥99% and that no dust overflows.

[0020] A further technical solution is that, in step S4, the wastewater generated by the spray rinsing is treated by sedimentation in a three-stage sedimentation tank, and the supernatant is recycled back to the rinsing process.

[0021] A further technical solution is that the cleaning parameters include water pressure and rinsing time, wherein the water pressure is set to 0.3MPa-0.5MPa and the cleaning time is set to 1 min-2 min.

[0022] A further technical solution is that the clamp is a special clamp with a rubber buffer pad, and the clamping force is controlled at 5kN-8kN to ensure that the medium box is free from displacement and rigid impact.

[0023] Compared with the prior art, the beneficial effects of the present invention are: 1. Achieve 100% non-destructive deep cleaning, reducing spare parts costs by over 60%. This invention completely abandons the traditional approach of using strong impact cleaning. Through critical temperature interface embrittlement and uniform inertial force peeling, the entire process involves no mechanical impact, no high-temperature damage, and no chemical corrosion. The damage rate of the medium cartridge is reduced from 5% to 0, and the average service life is extended by more than 30%. For a large beneficiation plant with 10 high-intensity magnetic separators, this can save more than 800,000 yuan in spare parts replacement costs annually.

[0024] 2. Batch and continuous operation improves cleaning efficiency by more than 15 times. This invention shortens the traditional natural air-drying cycle of 3-7 days to a few hours. The total cleaning time for a single strong magnetic machine with 192 media boxes is ≤8 hours, which is more than 15 times faster than manual knocking. This significantly reduces the equipment downtime for maintenance and increases the continuous operation rate of the mineral processing production line by more than 5%.

[0025] 3. Thorough cleaning effect, sorting performance fully restored to the level of a new media cartridge. The three-step synergistic process can thoroughly remove the hardened clay and clogged coarse particles deep within the gaps of the toothed plates. After cleaning, the permeability of the gaps in the toothed plates of the media box is restored to 100%, and the magnetic permeability is completely consistent with that of a new media box. Field production verification shows that after the cleaned media box is installed in the machine, the recovery rate of ilmenite roughing is increased by more than 20% compared to manual cleaning, and the online service life is extended by more than 50%.

[0026] 4. The entire process is green and safe, completely eliminating occupational health and environmental risks. The entire process is mechanized, requiring operators to only complete loading, unloading, and parameter settings, completely eliminating the need for strenuous physical labor; the vibration desliming process uses sealed dust removal + negative pressure dust collection, with a dust collection efficiency of ≥99%; no chemical agents are added throughout the process, and the wastewater recycling rate is ≥90%, fully meeting the national requirements for green mine construction.

[0027] 5. Highly adaptable to various processes, enabling rapid large-scale deployment. The method of this invention is compatible with the media box cleaning of various mainstream vertical high gradient strong magnets such as the SLon series. The process parameters can be flexibly adjusted according to the degree of blockage and size specifications. The operation process is standardized and does not require complicated manual operation. It can be directly applied to various large, medium and small ilmenite and hematite beneficiation plants. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] Example 1 This embodiment provides a non-destructive offline cleaning method for the media box of a high-intensity magnetic concentrator, applicable to the offline cleaning of clogged media boxes in vertical pulsating high-gradient high-intensity magnetic concentrators used for ilmenite beneficiation. The method is characterized by the following steps: S1: Disassembly and pretreatment: Remove the clogged media box to be cleaned from the main unit of the high-intensity magnet generator, remove the loose minerals and large debris from the surface of the media box, and obtain the media box to be cleaned; S2: Critical Temperature Interface Embrittlement Drying: Place the medium box to be cleaned into a hot air circulating drying oven, set the drying parameters of the hot air circulating drying oven to dry the medium box, so that the blockage sludge in the gap of the magnetic tooth plate of the medium box undergoes complete removal of interlayer water and irreversible lattice shrinkage, and uniform microcracks are formed at the interface between the sludge and the tooth plate. The sludge as a whole forms embrittled sludge in a brittle and fragmented state, and the dried medium box is obtained. S3: Uniform inertial force non-destructive desliming: The dried media box is locked and fixed on the vibration platform by clamps; after setting the vibration parameters optimized by modal test and finite element analysis, the vibration device is started. The vibration parameters match the interface peeling energy between the embrittled sludge and the toothed plate, and the vibration energy is lower than the structural fatigue threshold of the media box, and the vibration frequency is lower than the first natural frequency of the media box, so that the embrittled sludge is peeled off as a whole under the action of uniform inertial force. S4: Self-cleaning effect low-pressure spray: Transfer the media box after vibration desliming to the closed rinsing station, set the cleaning parameters and use clean water to spray the media box from the top, left and right sides to remove the residual dust and sludge on the media box, and obtain a clean media box. S5: Performance Inspection: The clean media cartridges are inspected for appearance, dimensional accuracy, and magnetic permeability. Media cartridges that pass the inspection are directly installed and used. Media cartridges that fail the inspection are cleaned again by repeating steps S2-S4.

[0030] This invention employs a dual verification standard of industrial endoscope visual inspection and gravimetric residual measurement to achieve objective quantitative detection of gap permeability and avoid subjective judgment errors. 1. Industrial endoscopic inspection method Sampling rules: After each batch is cleaned, at least 10% of the media boxes shall be randomly selected for testing; if any unqualified products are found, the sampling shall be doubled for retesting, and if they are still unqualified, the entire batch shall be cleaned again.

[0031] Inspection method: Using an industrial endoscope with a resolution of ≥2 million pixels and a probe diameter of ≤2mm, each test media cartridge is scanned line by line to inspect all toothed plate gaps (a single standard media cartridge contains 120 evenly distributed toothed plate gaps).

[0032] Judgment criteria: If there is no visible sludge or coarse particles blocking a single gap, and the area covered by residual dust is ≤1% of the total gap area, the gap is considered to be transparent; if the proportion of transparent gaps in a single media box to the total number of gaps is ≥99%, the media box is considered to be qualified.

[0033] 2. Gravimetric method for determining residual content (core quantitative indicator) Testing steps: Take the clean media box to be tested and dry it at 105℃ to constant weight, and record it as m0 (net weight of the media box itself). The medium box was thoroughly rinsed with a 20MPa high-pressure water gun, and all rinsing wastewater was collected. After filtration through a 0.45μm filter membrane, the filter residue was dried at 105℃ to constant weight to obtain the residual sludge mass m1. Calculate the residual sludge rate: Residual sludge rate = m1 / (m before blockage - m0)×100%, where m before blockage is the initial constant weight of the media box before use.

[0034] In a preferred embodiment, the drying parameters include a drying time of 3-9 hours and a drying temperature of 180℃-198℃, so that the drying temperature is precisely controlled below the thermal damage threshold of 200℃ for the magnetic toothed plate, with a temperature control accuracy of ±2℃ and a temperature uniformity deviation within the chamber ≤ ±5℃. The drying parameters were determined experimentally, showing that the interfacial bonding force of the ilmenite beneficiation slime (mainly kaolinite and montmorillonite) is not linearly related to the drying temperature, but rather undergoes a sudden change within the 180℃-198℃ range. When the temperature is <180℃, the clay minerals only lose free water, but a large amount of interlayer water still exists. The clay is in a plastic state, and the interfacial bonding force with the toothed plate remains above 80% of the original value. The vibration shedding rate is <60%. When the temperature is between 180℃ and 198℃, the interlayer water of clay minerals is completely removed, the crystal lattice undergoes irreversible shrinkage, the volume shrinkage rate reaches 12% to 15%, uniformly distributed microcracks are formed at the interface between the mud and the tooth plate, the interfacial bonding force drops sharply to less than 5% of the original value, and the mud as a whole is in a brittle and fragmented state. When the temperature is above 198℃, even if it only increases by 2℃, trace oxidation begins to appear at the grain boundaries of the magnetic stainless steel, and thermal stress begins to accumulate. After 3 to 5 cleaning cycles, the magnetic permeability will decrease by more than 10%, microcracks will appear in the weld, and long-term use will lead to the failure of the medium cartridge.

[0035] In a preferred embodiment, in step S2, the moisture content of the sludge in the gap between the toothed plates of the media box to be cleaned is determined by the drying weight method; when the moisture content of the sludge is >15%, it is classified as a severely clogged media box, and the drying time is set to 7h-9h; when the moisture content of the sludge is ≤15%, it is classified as a lightly clogged media box, and the drying time is set to 3h-5h; after drying, the moisture content of the sludge in the gap between the media box to be cleaned is ≤3%.

[0036] Among them, the measurement points for determining the moisture content of the sludge in the gap between the tooth plates of the medium box to be cleaned by the drying weight method are after the disassembly and pretreatment in step S1 and before drying in step S2. Step S1 is a dry cleaning method (wire brush cleaning + compressed air blowing), which does not introduce additional moisture throughout the process, ensuring that the moisture content reflects the true state of the original blockage sludge in the gap between the tooth plates.

[0037] The test uses the drying weight method: blockage mud is taken from the depth of the gap between the toothed plates at three points: the middle and the corners of the medium box. After mixing, 10g of sample is weighed and placed in a forced-air drying oven at 105℃±5℃ to dry to constant weight. The moisture content is calculated according to the formula "moisture content = (wet weight - dry weight) / wet weight × 100%", which is used as the basis for grading the degree of blockage.

[0038] In a preferred embodiment, the vibration parameters include a vibration frequency of 25 Hz-50 Hz, an amplitude of 1 mm-3 mm, and a vibration time of 3 min-5 min.

[0039] In a preferred embodiment, in step S3, when the media box to be cleaned is a heavily clogged media box, the vibration frequency is set to 40 Hz-50 Hz, the amplitude is 2mm-3mm, and the vibration time is 4min-5min; when the media box to be cleaned is a lightly clogged media box, the vibration frequency is set to 25 Hz-35 Hz, the amplitude is 1mm-2mm, and the vibration time is 3min-4min.

[0040] In a preferred embodiment, the first-order natural frequency in step S3 is determined by a combination of hammer impact modal testing and finite element simulation verification.

[0041] Specifically, this invention uses a combination of hammer impact modal testing and finite element simulation to determine the first natural frequency of the dielectric cell, ensuring accurate and reliable results. (1) Hammer impact modal test (actual measurement): (2) The test object was a standard dielectric cell of a SLon-4500 vertical pulsating high gradient magnetometer (600mm×300mm×100mm, with 0Cr13 magnetically conductive stainless steel for the magnetic tooth plate). Five piezoelectric accelerometers (sensitivity 100mV / g) were arranged at the four corners and center of the top surface of the dielectric cell. A force hammer was used to apply pulse excitation at nine evenly distributed excitation points on the top surface of the dielectric cell. Each excitation point was tested three times and the average value was taken. The response signal was acquired using a dynamic signal analyzer (sampling frequency 1024Hz, frequency resolution 0.5Hz), and the first natural frequency of the dielectric cell was extracted using modal analysis software.

[0042] (2) Finite element simulation verification: A three-dimensional solid model of the dielectric cell was established, fully including the toothed plate, frame, and weld structure. Material parameters were set as follows: 0Cr13 magnetic stainless steel with an elastic modulus of 206 GPa, Poisson's ratio of 0.3, and density of 7850 kg / m³. A tetrahedral element mesh (5 mm mesh size) was used, and constraints consistent with actual working conditions were applied (simulating the locking state of the special fixture, constraining the translational degrees of freedom of the fixture contact area). The simulated first-order natural frequency of the dielectric cell was calculated, with a deviation of ≤3% from the measured value, verifying the accuracy of both the model and the measured results.

[0043] The natural frequencies of the media cartridges were tested for three typical loading states during the cleaning process, and the results are as follows: Based on the above results, the present invention selects a vibration frequency range of 25Hz to 50Hz. Even considering a frequency drift of ±20% (the upper limit is 50Hz × 1.2 = 60Hz), it is still lower than the lowest first-order natural frequency (49.5Hz) under all loading conditions, fundamentally eliminating the possibility of resonance and ensuring the safety of the dielectric box structure.

[0044] In a preferred embodiment, in step S3, the uniform inertial force non-destructive desliming process is carried out inside a sealed dust collector hood, and the mineral dust generated by the vibration is collected and treated by a bag filter under negative pressure to ensure that the dust collection efficiency is ≥99% and that no dust overflows.

[0045] In a preferred embodiment, in step S4, the wastewater generated by the spray rinsing is treated by sedimentation in a three-stage sedimentation tank, and the supernatant is recycled back to the rinsing process.

[0046] In a preferred embodiment, the cleaning parameters include water pressure and rinsing time, wherein the water pressure is set to 0.3MPa-0.5MPa and the cleaning time is set to 1 min-2 min.

[0047] In this invention, the safe parameter range for vibration cleaning of the medium box is determined through modal testing and finite element analysis. Drying provides a non-destructive basis for vibration: if the wet sludge is not dried at the critical temperature, even with the same vibration parameters, the shedding rate will be less than 20%; to achieve the same shedding rate, the vibration amplitude needs to be increased to more than 10 mm, which will directly lead to damage to the media box structure.

[0048] Vibration provides self-cleaning conditions for spraying: after drying and vibration, the extremely thin layer of sludge remaining on the surface of the toothed plate is in a brittle and loose state, and the surface negative charge density is reduced by 40%, so that low-pressure water of 0.3 MPa - 0.5 MPa can completely remove the residue; while for the media box that has not been vibrated, even if high-pressure water of 20 MPa is used, the residue rate in the deep crevices is still >30%.

[0049] The three-step synergy resulted in the additional effect of extending the online service life: the cleaned tooth plate surface formed a uniform micro-roughness and had no residual sticky sludge substrate, which reduced the adhesion rate of subsequent sludge by more than 50%, extending the online service life from 45 days to more than 72 days.

[0050] The corresponding vibration parameters were then obtained: vibration frequency: 25Hz~50Hz (lower than the first natural frequency of 60Hz to avoid resonance); amplitude: 1mm~3mm (the maximum stress of the medium box is only 1 / 20 of the yield strength, far below the fatigue threshold); vibration time: 3~5min (just enough to complete the stripping of all embrittled sludge, with no excess energy accumulation).

[0051] This parameter range is not the result of conventional optimization, but rather a precise match between the mechanical properties of the media box structure and the stripping energy of the embrittled slime. The stress corresponding to the impact force generated by traditional manual hammering is 3-5 times that of the vibration stress of this invention, which will inevitably lead to damage to the media box.

[0052] The cleaning method described above in this invention differs fundamentally from existing technologies, as detailed in the table below: Example 2 Based on Example 1, the object of this example is the blockage medium box of a SLon-4500 vertical pulsating high gradient strong magnetizer in a titanium beneficiation plant in Xichang, Sichuan. Each strong magnetizer is equipped with 192 medium boxes, each with a size of 600mm×300mm×100mm. The magnetic tooth plate is made of 0Cr13 magnetic stainless steel with a thermal damage threshold of 200℃. The medium box is heavily blocked by clay minerals with a blockage rate of ≥80% and a sludge moisture content of 18%.

[0053] The specific cleaning steps are as follows: S1 Disassembly Pre-treatment: After shutdown, remove the 192 blockage media boxes one by one, use a wire brush to remove loose minerals and large debris from the outer surface, and sort and stack them according to the degree of blockage.

[0054] S2 Critical Temperature Drying: The media boxes are placed in batches of 32 pieces into a hot air circulating drying oven with PID temperature control, arranged in layers with a 50mm ventilation gap between layers; the drying temperature is set to 195℃, the temperature control accuracy is ±2℃, the temperature uniformity deviation inside the oven is ≤±3℃, and the drying is carried out at a constant temperature for 7 hours; after drying, the moisture content of the sludge is 2.2%, it is completely dry and cracked and white, the micro-cracks at the interface are evenly distributed, and the magnetic permeability is not reduced.

[0055] S3 Uniform Vibration Desliming: Remove the media box and cool it to room temperature. Secure it to the vibration platform with a special clamp with an 8mm thick rubber buffer pad and a locking force of 6kN. Close the sealed dust collector cover, start the bag filter, and then start the vibration motor. Set the vibration frequency to 45Hz and the amplitude to 2.5mm, and vibrate continuously for 4.5min. During the vibration process, a large amount of dry mineral dust can be seen falling off in a waterfall-like manner and is all collected by the bag filter.

[0056] S4 Low-pressure spray cleaning: The media box is transferred to a closed rinsing station, and a three-way spray pipeline is used to spray clean water at 0.4MPa for 1.5 minutes; the rinsing wastewater is reused after sedimentation in a three-stage sedimentation tank, with a water resource recycling rate of 92%.

[0057] S5 Performance Inspection: All media boxes are in good condition, the toothed plates are free from deformation, the welds are free from cracks, the dimensional accuracy is free from deviation, the magnetic conductivity meets the requirements, and the gap transparency is 100%. They can be directly installed and used.

[0058] The total process time in this embodiment is 7.5 hours, with no damage to the media box; after installation and operation, the recovery rate of ilmenite roughing is increased by 21.3% compared with manual cleaning, and the online use period is extended from 45 days to 72 days.

[0059] Example 3 Based on Example 1, the object of this example is the blockage medium box of the SLon-3000 strong magnet in a titanium beneficiation plant in Panzhihua, Sichuan. Each unit is equipped with 96 boxes, which are slightly blocked with a blockage rate of 30% to 40% and a sludge moisture content of 12%.

[0060] The specific cleaning steps are as follows: S1 Disassembly Pre-treatment: Remove the media box and clean the surface of floating minerals and debris.

[0061] S2 Critical Temperature Drying: Set the drying temperature to 185℃ and dry at a constant temperature for 4 hours; after drying, the sludge moisture content is 2.8%, it is completely cracked and embrittled, and the magnetic conductivity is not reduced.

[0062] S3 Uniform Vibration Desliming: Locking force 5kN, vibration frequency 30Hz, amplitude 1.5mm, continuous vibration for 3min; fully sealed dust collection.

[0063] S4 Low-pressure spray cleaning: 0.35MPa clean water spray for 1 minute, wastewater is recycled.

[0064] S5 performance test: all passed, ready for direct installation.

[0065] The total process time in this embodiment was 4 hours, with no damage to the media boxes; the sorting efficiency was 20.1% higher than that of manual cleaning.

[0066] As demonstrated by the above embodiments, this invention completely abandons the traditional approach of cleaning with strong impact. Through critical temperature interface embrittlement and uniform inertial force peeling, the entire process involves no mechanical impact, no high-temperature damage, and no chemical corrosion. The damage rate of the media box is reduced from 5% to 0, and the average service life is extended by more than 30%. For a large beneficiation plant with 10 high-intensity magnetic separators, this can save more than 800,000 yuan in spare parts replacement costs annually. It achieves 100% non-destructive deep cleaning, reducing spare parts costs by more than 60%.

[0067] This invention shortens the traditional natural air-drying cycle of 3-7 days to just a few hours. The total cleaning time for a single high-intensity magnetic separator with 192 media boxes is ≤8 hours, which is more than 15 times faster than manual tapping. This significantly reduces equipment downtime for maintenance and increases the continuous operation rate of the mineral processing production line by more than 5%. It ensures continuous batch operation and improves cleaning efficiency by more than 15 times.

[0068] The three-step synergistic process can thoroughly remove the hardened clay and clogged coarse particles deep within the gaps of the toothed plates. After cleaning, the permeability of the gaps in the toothed plates of the media box is restored to 100%, and the magnetic permeability is completely consistent with that of a new media box. Field production verification shows that after the cleaned media box is installed in the machine, the recovery rate of ilmenite roughing is increased by more than 20% compared to manual cleaning, and the online service life is extended by more than 50%, achieving thorough cleaning and fully restoring the sorting performance to the level of a new media box.

[0069] The entire process is mechanized, requiring operators to only complete loading, unloading, and parameter settings, completely eliminating the need for strenuous physical labor; the vibration desliming process uses sealed dust removal + negative pressure dust collection, with a dust collection efficiency of ≥99%; no chemical agents are added throughout the process, and the wastewater recycling rate is ≥90%, fully meeting the national green mine construction requirements, achieving green and safe operation throughout the entire process, and completely eliminating occupational health and environmental risks.

[0070] The method of this invention is compatible with the media box cleaning of various mainstream vertical high gradient strong magnets such as the SLon series. The process parameters can be flexibly adjusted according to the degree of blockage and size specifications. The operation process is standardized and does not require complicated manual operation. It can be directly applied to various large, medium and small ilmenite and hematite beneficiation plants, ensuring strong process adaptability and rapid large-scale promotion.

[0071] Comparative Example 1 (Critical Temperature Boundary Verification) This comparative study treated the same batch of heavily clogged media boxes (sludge moisture content 18%, clog rate ≥80%) as Example 1, only changing the drying temperature. All other steps (drying time 7h, vibration parameters 45Hz / 2.5mm / 4.5min, spray parameters 0.4MPa / 1.5min) were identical to Example 1. Sixteen media boxes were tested at each temperature point, and after 10 consecutive cleaning cycles, various indicators were measured. The test results are as follows: The above data shows that within the temperature range of 180℃-198℃, the decay rate of magnetic permeability after 10 cleaning cycles is stable at 1.5%-1.8%. This decay is due to the reversible slight magnetic hysteresis change of magnetic stainless steel under low temperature thermal cycling, rather than irreversible grain boundary oxidation or structural damage.

[0072] According to the provisions of the industry standard "Technical Specifications for Magnetic Permeable Media for High Gradient Magnetic Separators" (YB / T 4573-2016), a magnetic permeability attenuation rate of ≤5% after normal use and maintenance of the magnetic permeable medium is qualified. The attenuation rate of 1.8% of the present invention is far lower than the industry allowable threshold, and the cumulative attenuation rate is still ≤3% throughout the entire service life cycle of the medium box (about 50 cleaning cycles), which fully meets the definition of "non-destructive". However, when the temperature exceeds 198℃ and reaches 200℃, the magnetic permeability attenuation rate suddenly rises to 11.3%, and irreversible weld microcracks appear, which clearly falls into the category of thermal damage.

[0073] Comparative Example 2 (Vibration Parameter Boundary Verification) In this comparative example, the medium boxes from the same batch as in Example 1 and dried at 195℃ are treated, only the vibration parameters are changed, and the rest of the steps are completely the same as those in Example 1. The results are as follows: The results show that 25Hz-50Hz and 1mm-3mm is the only non-destructive vibration safety window that simultaneously satisfies "high shedding rate" and "zero structural damage".

[0074] Comparative Example 3 (Synergistic Effect Verification) In this comparative example, heavily blocked medium boxes from the same batch as in Example 1 are treated by using separate steps or different combinations respectively, and the results are as follows: The results show that the synergistic effect of the three steps produces a technical effect of "1+1+1>3", and any single step or the absence of any one step cannot achieve the comprehensive performance of the present invention.

[0075] Comparative Example 4 (Traditional Manual Cleaning) In this comparative example, 192 heavily blocked medium boxes from the same batch as in Example 1 are treated by the traditional industry manual cleaning method. The results are: the total duration of the whole process is 6 days, 9 boxes are damaged (damage rate 4.69%), the gap permeability is 72%, the installation recovery rate is 21.5% lower than that of Example 1, the on-line service life is 42 days, and the unorganized dust emission during the operation process is serious.

[0076] Although the invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter combination within the scope of the disclosure and claims. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A non-destructive offline cleaning method for the media box of a high-intensity magnetic concentrator, applicable to the offline cleaning of clogged media boxes in vertical pulsating high-gradient high-intensity magnetic concentrators used for ilmenite beneficiation, characterized in that... Includes the following steps: S1: Disassembly and pretreatment: Remove the clogged media box to be cleaned from the main unit of the high-intensity magnet generator, remove the loose minerals and large debris from the surface of the media box, and obtain the media box to be cleaned; S2: Critical Temperature Interface Embrittlement Drying: Place the medium box to be cleaned into a hot air circulating drying oven, set the drying parameters of the hot air circulating drying oven to dry the medium box, so that the blockage sludge in the gap of the magnetic tooth plate of the medium box undergoes complete removal of interlayer water and irreversible lattice shrinkage, and uniform microcracks are formed at the interface between the sludge and the tooth plate. The sludge as a whole forms embrittled sludge in a brittle and fragmented state, and the dried medium box is obtained. S3: Uniform inertial force non-destructive desliming: The dried media box is locked and fixed on the vibration platform by clamps; after setting the vibration parameters optimized by modal test and finite element analysis, the vibration device is started. The vibration parameters match the interface peeling energy between the embrittled sludge and the toothed plate, and the vibration energy is lower than the structural fatigue threshold of the media box, and the vibration frequency is lower than the first natural frequency of the media box, so that the embrittled sludge is peeled off as a whole under the action of uniform inertial force. S4: Self-cleaning effect low-pressure spray: Transfer the media box after vibration desliming to the closed rinsing station, set the cleaning parameters and use clean water to spray the media box from the top, left and right sides to remove the residual dust and sludge on the media box, and obtain a clean media box. S5: Performance Inspection: The clean media cartridges are inspected for appearance, dimensional accuracy, and magnetic permeability. Media cartridges that pass the inspection are directly installed and used. Media cartridges that fail the inspection are cleaned again by repeating steps S2-S4.

2. The non-destructive offline cleaning method for a strong magnetic medium box according to claim 1, characterized in that: The drying parameters include a drying time of 3-9 hours and a drying temperature of 180℃-198℃, so that the drying temperature is precisely controlled below the thermal damage threshold of 200℃ for the magnetic tooth plate, and the temperature control accuracy is ±2℃, and the temperature uniformity deviation inside the chamber is ≤±5℃.

3. The non-destructive offline cleaning method for a strong magnetic medium box according to claim 1, characterized in that: In step S2, the moisture content of the sludge in the gap between the toothed plates of the media box to be cleaned is determined by the drying weight method; when the moisture content of the sludge is >15%, it is classified as a severely clogged media box, and the drying time is set to 7h-9h; when the moisture content of the sludge is ≤15%, it is classified as a lightly clogged media box, and the drying time is set to 3h-5h. After drying, the moisture content of the sludge in the gaps of the media box to be cleaned is ≤3%.

4. The non-destructive offline cleaning method for a strong magnetic medium cartridge according to claim 3, characterized in that: The vibration parameters include a vibration frequency of 25 Hz-50 Hz, an amplitude of 1 mm-3 mm, and a vibration time of 3 min-5 min.

5. The non-destructive offline cleaning method for a strong magnetic medium box according to claim 3, characterized in that: In step S3, when the media box to be cleaned is a severely clogged media box, the vibration frequency is set to 40 Hz-50 Hz, the amplitude is 2mm-3mm, and the vibration time is 4min-5min; when the media box to be cleaned is a slightly clogged media box, the vibration frequency is set to 25Hz-35Hz, the amplitude is 1mm-2mm, and the vibration time is 3min-4min.

6. The non-destructive offline cleaning method for a strong magnetic medium box according to claim 1, characterized in that: In step S3, the first-order natural frequency is determined by a combination of hammer impact modal testing and finite element simulation verification.

7. The non-destructive offline cleaning method for a strong magnetic medium box according to claim 1, characterized in that: In step S3, the uniform inertial force non-destructive desliming process is carried out inside a sealed dust collector. The mineral dust generated by the vibration is collected and treated by a bag filter under negative pressure to ensure that the dust collection efficiency is ≥99% and that no dust overflows.

8. The non-destructive offline cleaning method for a strong magnetic medium box according to claim 1, characterized in that: In step S4, the wastewater generated by the spray rinsing is treated by sedimentation in a three-stage sedimentation tank, and the supernatant is recycled back to the rinsing process.

9. The non-destructive offline cleaning method for a strong magnetic medium box according to claim 1, characterized in that: The cleaning parameters include water pressure and rinsing time, with the water pressure set to 0.3MPa-0.5MPa and the cleaning time set to 1 min-2 min.

10. A non-destructive offline cleaning method for a strong magnetic medium cartridge according to claim 1, characterized in that: The clamp is a special clamp with a rubber buffer pad. The clamping force is controlled at 5kN-8kN to ensure that the media box is free from displacement and rigid impact.

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