Iron tailing recleaning and recycling equipment based on mechanical suspension magnetizing roasting technology

Abstract

The invention discloses iron tailing recleaning and recycling equipment based on a mechanical suspension magnetizing roasting technology, and the equipment comprises a pretreatment grinding mechanism which is used for screening and grinding iron tailings; the suspension magnetization roasting device is connected with a discharge hole of the pretreatment grinding mechanism and comprises a suspension magnetization roasting furnace and a mechanical stirring structure; the mechanical stirring structure is located in the suspension magnetization roasting furnace and comprises a spiral gap baffle impeller with a hole structure, and the gap baffle impeller is driven by a first driving mechanism and can rotate forwards and backwards to correspond to a roasting stirring mode and a discharging mode respectively. The magnetic separation device is connected with a roasted product outlet of the suspension magnetization roasting device and is used for separating magnetic minerals; and the tail gas recovery treatment device is used for recovering and treating the tail gas and separating out sodium chloride crystals to be reused in the suspension magnetization roasting device. According to the method, water suspension is replaced by a mechanical suspension method, water iron oxide in the roasting process is avoided, and recycling of materials such as a chlorinating agent and tail gas is achieved.

Description

Technical Field

[0001] This invention relates to the field of iron tailings roasting and magnetic separation technology, specifically to an iron tailings reprocessing and recovery device based on mechanical suspension magnetization roasting technology. Background Technology

[0002] The large accumulation of iron tailings not only leads to land occupation but also poses a threat to the ecological environment of the mining area and its surrounding areas, thus requiring the recycling of iron tailings.

[0003] The existing method for recycling iron tailings is to suspend and roast the iron tailings with water, adsorb the iron tailings with permanent magnets, and then wash them with water or a scraper. This method has many disadvantages and problems. The main problems are: (1) At high temperatures, water acts as an oxidant, causing iron to be oxidized into iron oxide, thereby reducing the iron production and causing a large amount of wastewater discharge; (2) The magnetic strength of the permanent magnet is fixed and it is not easy to adjust it in time; (3) It is necessary to use water or a scraper to scrape off the magnetized iron ore, which will cause a large waste of water resources or wear and tear on the magnetic separation equipment; (4) Traditional recycling equipment cannot dynamically adjust factors such as temperature control and magnetic field in real time, and can only set the corresponding parameters in advance; if the temperature control is not timely, it may lead to insufficient reduction reaction, reduced magnetic mineral production, and decreased magnetic separation efficiency; (5) There is no good flue gas recovery device or by-product recycling device, resulting in low resource utilization and poor energy saving and emission reduction effects.

[0004] Therefore, a complete set of iron tailings recovery equipment needs to be designed to avoid iron oxidation by water during roasting; to recover materials such as chlorinating agents; to achieve precise magnetic separation and temperature control; and to recover tail gas and increase resource utilization. Summary of the Invention

[0005] The main objective of this invention is to provide an iron tailings reprocessing and recycling device based on mechanical suspension magnetization roasting technology. This device uses mechanical suspension instead of water suspension to avoid iron oxidation during the roasting process, thereby enabling the recovery of materials such as chlorinating agents and the treatment of tail gas.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides an iron tailings reprocessing and recovery device based on mechanical suspension magnetization roasting technology, the device comprising: The pretreatment grinding unit is used for screening and grinding iron tailings; A suspension magnetization roasting device, connected to the discharge port of a pretreatment grinding mechanism, includes a suspension magnetization roasting furnace and a mechanical stirring structure. The mechanical stirring structure is located inside the suspension magnetization roasting furnace and includes a spiral-shaped gap baffle impeller with a perforated structure. The gap baffle impeller is driven by a first driving mechanism and can rotate in both directions, corresponding to the roasting stirring mode and the discharge mode, respectively. In the roasting stirring mode, the first driving mechanism drives the gap baffle impeller to rotate forward, and the iron tailings are carried upward by the spiral-shaped gap baffle impeller and then poured to the bottom of the furnace body, where they come into full contact with the gas generated by the heating reaction of the chlorinating agent inside the furnace body. In the discharge mode, the first driving mechanism drives the gap baffle impeller to rotate in reverse, and the iron tailings are sent to the roasting product outlet of the suspension magnetization roasting furnace by the spiral-shaped gap baffle impeller, while the chlorinating agent remains in the suspension magnetization roasting furnace through the perforated structure of the gap baffle impeller. A magnetic separation device is connected to the roasting product outlet of a suspension magnetized roasting device and is used to separate magnetic minerals. The exhaust gas recovery and treatment device is connected to the flue gas outlet of the suspension magnetized roasting device, and includes an alkaline reaction chamber, a gas-liquid separator, and a crystallization unit. The alkaline reaction chamber is used to introduce alkaline reactants to neutralize the acidic flue gas. The gas-liquid separator is used to separate the clean gas and liquid after the neutralization reaction. The crystallization unit is used to evaporate and crystallize the liquid to separate sodium chloride crystals for reuse in the suspension magnetized roasting device.

[0007] Following the above technical solution, the pretreatment grinding mechanism includes: The screening mechanism is equipped with sieve plates of different aperture sizes to separate and screen small and large iron tailings particles. The high-homogeneity shearing mechanism is connected to the large particle outlet of the screening mechanism and is used to refine, grind and crush large iron tailings. A one-way valve is connected to the small particle outlet of the screening mechanism and the outlet of the high homogeneous shearing mechanism to control the unidirectional and uniform feeding of materials.

[0008] According to the above technical solution, the one-way valve includes a connecting flange pipe, a valve body, a valve seat, a valve disc, a valve cover, and a lifting ring; there are two connecting flange pipes, one connecting the valve body inlet to the small particle outlet of the screening mechanism and the outlet of the high homogeneous shearing mechanism, and the other connecting the valve body outlet to the suspension magnetization roasting device; the valve seat and valve disc are located inside the valve body and are used to control the unidirectional uniform feeding of materials; the valve cover is located on the top of the valve body, and the lifting ring is located on the top of the valve cover.

[0009] According to the above technical solution, the magnetic separation device includes a roasting product collection channel, an air pump, a Y-shaped structure, an annular magnet, and a second drive mechanism; The roasting product collection channel has a roasting product collection port, which is directly opposite the roasting product outlet of the suspension magnetized roasting device, for collecting roasting products. One end of the roasting product collection channel is connected to an air pump, and the other end is connected to the bottom of the Y-shaped structure, for blowing the collected roasting products to the Y-shaped structure. The two branches of the Y-shaped structure are a recovery channel and a discharge channel, respectively. The recovery channel is connected to the suspension magnetized roasting device. The annular magnet is located at the branch of the Y-shaped structure. It generates a magnetic force that attracts the iron tailings, causing the iron tailings to enter the discharge channel, while other roasting products enter the recovery channel and are recovered to the suspension magnetized roasting device. The annular magnet has multiple magnets with different magnetic field strengths arranged at intervals along its circumference. The second drive mechanism is connected to the annular magnet and drives the annular magnet to rotate and switch the magnets to adjust the magnetic field strength at the branch.

[0010] Following the above technical solution, the alkaline reaction chamber is a vertical cylindrical container, internally divided into upper and lower layers: The upper layer is a spray reaction chamber, used to introduce alkaline reactants to neutralize acidic flue gas; The lower layer is a sedimentation collection chamber, which has a conical bottom to collect the liquid and precipitate after the reaction.

[0011] According to the above technical solution, the alkaline reaction chamber is equipped with an exhaust port at the top and a slag discharge valve and a belt drive mechanism at the bottom; the slag discharge valve is equipped with upper and lower baffle doors and a pneumatic-hydraulic push rod, and the opening and closing of the upper and lower baffle doors is controlled by the pneumatic-hydraulic push rod; the belt drive mechanism discharges slag through the slag discharge valve. The conical opening at the bottom of the sedimentation collection chamber is equipped with a planetary gear stirrer to prevent clogging.

[0012] Following the above technical solution, the gas-liquid separator adopts a cyclone separator design with an internal spiral guide plate. The flue gas enters tangentially, the clean gas is discharged from the top, and the liquid flows out from the bottom to the crystallization unit.

[0013] According to the above technical solution, the crystallization unit includes an evaporator and a crystallizer; the evaporator is used to concentrate the liquid, and the crystallizer is equipped with a cooling component and a crystallization tank. The cooling component causes the concentrated liquid to crystallize in the crystallization tank and be reused in the suspension magnetization calcination device.

[0014] Following the above technical solution, the equipment also includes a measurement and control system, which includes: The first laser particle size analyzer is installed in the pretreatment grinding mechanism to detect the size of iron tailings particles so that the iron tailings grinding meets the standards. The second laser particle size analyzer is installed in the suspension magnetization roasting furnace of the suspension magnetization roasting device to detect the size of iron tailings particles in order to control the roasting time; the larger the iron tailings particles, the longer the roasting time. The first temperature sensor is installed in the suspension magnetization roasting furnace of the suspension magnetization roasting device to control the roasting temperature; The second temperature sensor is installed in the evaporator of the crystallization unit of the exhaust gas recovery and treatment device to control the evaporator temperature. The Hall effect sensor, located on the annular magnet of the magnetic separator, is used to switch the magnet by controlling the rotation angle of the annular magnet according to the size of the iron tailings particles detected by the second laser particle size analyzer, so as to adjust the magnetic field strength at the bifurcation point; wherein, the larger the iron tailings particles, the stronger the magnetic field. Gas concentration sensor and pH sensor are installed in the alkaline reaction chamber of the exhaust gas recovery and treatment device to detect the concentration and pH value of acidic flue gas. If the concentration and pH value of acidic flue gas meet the standards, the exhaust port at the top of the alkaline reaction chamber will be opened. A flow sensor is installed at the bottom of the alkaline reaction chamber of the exhaust gas recovery and treatment device to detect the liquid flow rate and control the amount of alkaline reactant added.

[0015] Secondly, the present invention provides an iron tailings ore, which is recovered by the iron tailings reprocessing and recycling equipment based on mechanical suspension magnetization roasting technology as described in any one of the first aspects.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: This invention provides an iron tailings reprocessing and recovery device based on mechanical suspension magnetization roasting technology, including a pretreatment grinding mechanism, a suspension magnetization roasting device, a magnetic separation device, and a tail gas recovery and treatment device. The suspension magnetization roasting device is equipped with a reversible spiral-shaped gap baffle impeller, achieving mechanical suspension and full reaction of the iron tailings in roasting and stirring mode, and separating the iron tailings from the chlorinating agent in discharge mode. This device uses mechanical suspension instead of traditional water suspension, effectively avoiding the problem of iron oxidation to iron oxide caused by moisture at high temperatures, thus improving the iron recovery rate. Simultaneously, it enables the retention and recycling of the chlorinating agent within the furnace, and further extracts sodium chloride from the recovered tail gas for reuse in the roasting process, thereby improving overall resource utilization and reducing pollution emissions.

[0017] Furthermore, the magnetic separator adopts a conveying method with an air pump, combined with a Y-shaped structure and a ring magnet with magnets of various magnetic field intensities around its circumference. By rotating the ring magnet, the magnetic field intensity of the sorting area can be adjusted, realizing dynamic adjustment of the magnetic field intensity. This enables precise sorting of minerals of different particle sizes and magnetic properties, improves the recovery rate of magnetic minerals, and allows insufficiently magnetized materials to be returned to the roasting furnace for reprocessing, thereby improving the overall sorting efficiency and adaptability.

[0018] Furthermore, the exhaust gas recovery and treatment device includes an alkaline reaction chamber, a gas-liquid separator, and a crystallization unit. The alkaline reaction chamber employs a double-layer design to achieve flue gas neutralization and liquid collection. The gas-liquid separator utilizes a cyclone separation structure for efficient gas-liquid separation. The crystallization unit extracts sodium chloride through evaporation concentration and cooling crystallization. This exhaust gas recovery and treatment device not only effectively purifies acidic flue gas but also recovers valuable sodium chloride crystals for reuse in the roasting process, achieving reagent recycling and reducing operating costs and environmental burden. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of an iron tailings reprocessing and recovery device based on mechanical suspension magnetization roasting technology according to an embodiment of the present invention. Figure 2 This is a schematic diagram of a one-way valve according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a mechanical stirring structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a magnetic separation device according to an embodiment of the present invention; Figure 5 This is a three-dimensional schematic diagram of an exhaust gas treatment device according to an embodiment of the present invention; Figure 6 These are three views of an exhaust gas treatment device according to an embodiment of the present invention; Figure 7 This is a schematic diagram of an alkaline reaction chamber according to an embodiment of the present invention; Figure 8 This is a half-sectional view of the alkaline reaction chamber according to an embodiment of the present invention; Figure 9 This is an operational block diagram of an iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology according to an embodiment of the present invention. Figure 10 This is a schematic diagram of a measurement and control system according to an embodiment of the present invention.

[0020] In the diagram: 1. Pretreatment grinding mechanism; 2. Suspension magnetized roasting device; 3. Magnetic separation device; 4. Tail gas recovery and treatment device; 5. Support; 13. One-way valve; 131. Valve body; 132. Valve cover; 133. Valve disc; 134. Valve seat; 135. Connecting flange; 136. Lifting ring; 21. Mechanical stirring structure; 211. Hole structure; 212. Gap baffle impeller; 22. Motor; 23. Motor support; 24. Roasting product outlet; 31. Air 32. Air pump; 33. Ring magnet; 34. Belt; 45. U-shaped track structure; 46. Alkaline reaction chamber; 47. Gas-liquid separator; 48. Crystallization unit; 49. Spray reaction chamber; 40. Sedimentation collection chamber; 412. Slag discharge valve; 4131. Pneumatic-hydraulic push rod; 4132. Opening and closing door; 414. Pulley; 415. Planetary gear stirrer; 421. Spiral guide plate; 431. Evaporator; 432. Crystallizer; 433. Crystallization tank. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0022] Obviously, the accompanying drawings described below are merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0023] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention may be combined with other embodiments without conflict.

[0024] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," "an," "the," and similar words used in this invention do not indicate quantity limitation and may indicate singular or plural. The terms "comprising," "including," "having," and any variations thereof used in this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms "connected," "linked," "coupled," and similar words used in this invention are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "A plurality" used in this invention refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships may exist; for example, "A and / or B" can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects have an "or" relationship. The terms "first," "second," and "third" used in this invention are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0025] Traditional iron tailings treatment uses water suspension to suspend the iron tailings. At high temperatures, water acts as an oxidant, causing iron to oxidize into iron oxide, thus reducing iron production and generating significant wastewater discharge. Furthermore, traditional recovery equipment cannot dynamically adjust factors such as temperature and magnetic fields in real time; parameters must be preset. If temperature control is not timely, the reduction reaction may be incomplete, leading to a decrease in the formation of magnetic minerals and a drop in magnetic separation efficiency.

[0026] Based on this, the present invention proposes an iron tailings reprocessing and recovery device based on mechanical suspension magnetization roasting technology. This device innovatively replaces the traditional water-medium suspension process with mechanical suspension, avoiding the reduction in iron yield caused by water acting as an oxidant at high temperatures, which would lead to the oxidation of iron to iron oxide. Simultaneously, the fan-shaped impeller is designed with a perforated structure to recover the chlorinating agent while the impeller rotates. To improve the recovery rate of refined iron ore, a monitoring and control system is designed to convert non-magnetic materials into magnetic iron ore for magnetic separation. This system reduces tailings emissions by precisely controlling the strength of the magnetism at specific times. Meanwhile, the acidic flue gas from this device is neutralized by a tail gas treatment device, and the chlorinating agent is regenerated and recycled.

[0027] like Figure 1As shown, the iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology of the present invention includes a pretreatment grinding mechanism 1, a suspension magnetization roasting device 2, a magnetic separation device 3, a tail gas recovery and treatment device 4, and a measurement and control system. The entire equipment is constructed with an aluminum profile frame, and the aluminum profile is fixed to the equipment with horizontal and vertical bars to form a support frame 5.

[0028] The pretreatment grinding mechanism, used for screening and grinding iron tailings, includes a screening mechanism, a high-homogeneity shearing mechanism, and a one-way valve 13. The screening mechanism separates small and large particles of iron tailings using screens of different apertures and a rotating feedstock. Small particles fall directly to the bottom of the equipment for roasting, while large particles enter the high-shear homogenizer for fine grinding and crushing. The high-homogeneity shearing mechanism's high-speed rotor and stator perform high-speed grinding on the screened large-diameter iron tailings, achieving particle homogenization and grinding the iron tailings to be roasted to below 0.074mm. The one-way valve 13 is connected to the small particle outlet of the screening mechanism and the outlet of the high-homogeneity shearing mechanism to control the unidirectional and uniform feeding of materials.

[0029] like Figure 2 As shown, the one-way valve 13 includes a connecting flange pipe 135, a valve body 131, a valve seat 134, a valve disc 133, a valve cover 132, and a lifting ring 136. There are two connecting flange pipes 135, one connecting the inlet of the valve body 131 to the small particle outlet of the screening mechanism and the outlet of the high homogeneous shearing mechanism, and the other connecting the outlet of the valve body 131 to the suspension magnetization roasting device 2. The valve seat 134 and the valve disc 133 are located inside the valve body 131 and are used to control the material to be fed uniformly in one direction from left to right. The valve cover 132 is located on the top of the valve body 131, and the lifting ring 136 is located on the top of the valve cover 132 and can be used to open the valve cover 132.

[0030] During use, iron tailings are fed into the feed inlet and pass through the screening mechanism. Small particles fall directly to the bottom of the equipment for roasting, while large particles enter the high-shear homogenizer for fine grinding and crushing. The screened small iron tailings particles and the ground and crushed iron tailings particles enter the suspension magnetization roasting device 2 through the one-way valve 13.

[0031] The suspension magnetized roasting device 2 is connected to the outlet of the pretreatment grinding mechanism. It includes a suspension magnetized roasting furnace, a mechanical stirring structure 21, and a spraying device to spray the reducing agent chloride. A magnetic separator 3 is installed at the roasting product outlet 24, and a tail gas treatment device 4 is designed at the top. Figure 3As shown, the mechanical stirring structure 21 is located in the suspension magnetization roasting device 2. It has a perforated structure 211 with a diameter less than 50 micrometers and a gap baffle impeller 212. The mechanical stirring structure 21 is connected to the motor 22, which is fixed by a motor bracket 23, which is connected to the mechanical stirring structure. When the iron tailings enter the suspension magnetization roasting device 2 after passing through the pretreatment grinding mechanism, there is a chlorinating agent inside the furnace. The gap baffle impeller 212, driven by the motor 22, rotates clockwise. The material is driven upwards by the gap baffle impeller 212 and then tilted to the bottom. This results in a longer residence time of the material in the air, allowing it to fully contact the gas generated by the heating reaction of the chlorinating agent, thereby reducing it to metal chloride. The metal chloride is easily volatilized into gas at high temperatures, exiting from the flue and entering the tail gas recovery treatment device 4. After the reaction is complete, the motor rotates counterclockwise. Due to the blade tilt design, this state is the discharge state, and because of the gap perforated structure 211 in the gap baffle impeller 212, the chlorinating agent will not be discharged with the reaction products. Preferably, the mechanical stirring structure 21 is designed with an inclination angle of about 15 degrees (that is, the inclination angle of the suspension magnetization roasting furnace, which is determined by the height difference of the external support), and has an arc-shaped structure. The impeller is designed with holes with a diameter of 50 micrometers. The length of the stirring impeller is about 0.5m to achieve the separation of iron tailings and chlorinating agent. The chlorinating agent is recycled by the forward and reverse rotation of the motor.

[0032] The suspension magnetized roasting device 2 has two modes: roasting and stirring mode and discharge mode. The switching between roasting and discharge modes is achieved by using the forward and reverse rotation of the motor and the specific tilt angle of the mechanical impeller. In the roasting and stirring mode, the motor drives the gap baffle impeller 212 to rotate clockwise. The iron tailings are driven upward by the spiral gap baffle impeller 212 and then poured to the bottom of the furnace, where they come into full contact with the gas generated by the heating reaction of the chlorinating agent in the furnace. In the discharge mode, the motor drives the gap baffle impeller 212 to rotate in reverse. The iron tailings are sent to the roasting product outlet 24 of the suspension magnetized roasting furnace by the spiral gap baffle impeller 212, while the chlorinating agent remains in the suspension magnetized roasting furnace through the perforated structure 211 of the gap baffle impeller 212.

[0033] Magnetic separation device 3, connected to the roasting product outlet 24 of suspension magnetized roasting device 2, is used to separate magnetic minerals. For example... Figure 4As shown, the magnetic separation device 3 includes a roasting product collection channel, an air pump 31, a Y-shaped structure, an annular magnet 32, and a drive motor. It utilizes the magnetic differences of mineral particles to perform efficient magnetic separation. Magnetic mineral particles are attracted by the magnetic separation device and then move to the non-magnetic area to fall off, thus achieving the purpose of automatic collection. The roasting product collection channel has a roasting product collection port, which is directly opposite the roasting product outlet 24 of the suspension magnetized roasting device 2, for collecting roasting products. One end of the roasting product collection channel is connected to the air pump 31, and the other end is connected to the bottom of the Y-shaped structure, for blowing the collected roasting products to the Y-shaped structure. The two branches of the Y-shaped structure are the recovery channel and the discharge channel, respectively. The recovery channel is connected to the suspension magnetized roasting device, forming a U-shaped track structure 34. The annular magnet 32 ​​is located at the branch of the Y-shaped structure. It generates a magnetic force that attracts the iron tailings, causing the iron tailings to enter the discharge channel, while other roasting products enter the recovery channel and are recovered to the suspension magnetized roasting device 2. The annular magnet 32 ​​is circumferentially spaced with multiple magnets of different magnetic field strengths. The drive motor is connected to the annular magnet 32. By driving the annular magnet 32 ​​to rotate, the different magnet strengths are switched to adjust the magnetic field strength at the branch.

[0034] In this embodiment, there are two annular magnets 32, which are controlled by a motor via a belt 33. One annular magnet is located at the bifurcation of the Y-shaped structure, and the other is located in front of the bifurcation of the Y-shaped structure to provide a magnetic field in advance, so that the magnetic material is separated from the non-magnetic material in advance. The air pump 31 blows the roasted iron tailings into the magnetic separation device, where magnetic separation is achieved by the two annular magnets 32 and the Y-shaped structure.

[0035] like Figure 5 and Figure 6 As shown, the exhaust gas recovery and treatment device 4 is connected to the flue gas outlet of the suspension magnetization roasting device 2, and includes a flue gas collection and conveying pipeline, an alkaline reaction chamber 41, a gas-liquid separator 42, and a crystallization unit 43. The flue gas collection and conveying pipeline is designed to be inclined at an angle of approximately 15 degrees to prevent dust accumulation and is equipped with a dust vibrating screen. The alkaline reaction chamber is a vertical cylindrical container made of stainless steel, and is divided into upper and lower layers. The upper layer is a spray reaction chamber 411, and the lower layer is a sedimentation collection chamber 412. The bottom of the sedimentation collection chamber 412 is designed to be conical to collect the liquid and precipitate after the reaction, and is equipped with a small planetary gear agitator 415 to prevent clogging.

[0036] like Figure 8As shown, the alkaline reaction chamber 41 has an exhaust port at the top and a slag discharge valve 413 at the bottom. The slag discharge valve 413 has upper and lower baffle doors 4132 inside, and the doors are opened and closed by a pneumatic-hydraulic push rod 4131. Slag discharge is achieved dynamically through the transmission of a pulley 414. The alkaline reaction chamber 41 integrates a pH sensor and a concentration sensor, and the data is fed back to the PLC. If the concentration and pH value of the acidic flue gas in the alkaline reaction chamber 41 meet the standards, the exhaust port at the top of the alkaline reaction chamber 41 is opened, and the liquid and some gas are carried into the gas-liquid separator 42. The amount of alkaline solution added is automatically adjusted according to the liquid flow rate.

[0037] like Figure 7 As shown, the gas-liquid separator 42 adopts a cyclone separator design with a spiral guide plate 421 inside. The flue gas enters tangentially, the clean gas is discharged from the top, and the liquid flows out from the bottom. The inlet of the gas-liquid separator 42 is connected to the outlet of the alkaline reaction chamber 41, and the outlet is connected to the crystallization unit 43. The bottom liquid collection tank is connected to a pump to send the liquid to the crystallization unit 43.

[0038] Crystallization unit 43 includes an evaporator 431 and a crystallizer 432. Evaporator 431 uses a tubular heater, with the temperature controlled between 80 and 100 degrees Celsius. The concentrated liquid from crystallizer 432 enters crystallization tank 433, where NaCl and Na2SO4 crystallize through a cooling coil (water temperature approximately 20°C). Crystallization unit 43 is connected to liquid separator 42 via a pipeline, and a pump is used to transport the liquid. The crystallized NaCl is returned to the roasting furnace of the suspension magnetization roasting device via a screw conveyor for recycling as a chlorinating agent.

[0039] During use, the discharged industrial exhaust gas passes through the reaction chamber, where the alkaline reactants NaOH and baking soda react with the acidic gas. The resulting NaCl and Na2SO4 can be separated by physical crystallization through heated pipes. After recrystallization, NaCl can be recycled as a chlorinating agent, and NaOH can react with volatile heavy metals to form precipitates for removal.

[0040] The measurement and control system integrates an automatic control system that fuses multiple sensors, including temperature sensors, magnetic sensors, gas concentration sensors, and flow sensors, with mechanical devices to achieve deep closed-loop fusion. The measurement and control system mainly includes: The first laser particle size analyzer is installed in the pretreatment grinding mechanism to detect the size of iron tailings particles so that the iron tailings grinding meets the standards. The second laser particle size analyzer is installed in the suspension magnetization roasting furnace of the suspension magnetization roasting device to detect the size of iron tailings particles in order to control the roasting time; if the overall size is too large, the roasting time is increased accordingly; if the overall size is too small, the roasting time is shortened accordingly. The first temperature sensor is installed in the suspension magnetization roasting furnace of the suspension magnetization roasting device to control the roasting temperature; The second temperature sensor is installed in the evaporator of the crystallization unit of the exhaust gas recovery and treatment device to control the evaporator temperature. The Hall effect sensor, installed on the annular magnet of the magnetic separator, is used to adjust the magnetic field strength at the bifurcation point (sorting area) by switching the magnet according to the size of the iron tailings particles detected by the second laser particle size analyzer. The larger the iron tailings particles, the stronger the magnetic field. Gas concentration sensor and pH sensor are installed in the alkaline reaction chamber of the exhaust gas recovery and treatment device to detect the concentration and pH value of acidic flue gas. If the concentration and pH value of acidic flue gas meet the standards, the exhaust port at the top of the alkaline reaction chamber will be opened. A flow sensor is installed at the bottom of the alkaline reaction chamber of the exhaust gas recovery and treatment device to detect the liquid flow rate and control the amount of alkaline reactant added.

[0041] The overall monitoring and control system is controlled by a control panel and integrated into the project's monitoring and control system. Data (temperature, reaction chamber pH, salt production, magnetic field, iron tailings particle diameter) is displayed in real time via a web interface. A PID algorithm is used to automatically adjust parameters such as alkali flow rate and heating temperature.

[0042] Specifically, Figure 9 and Figure 10 This is a general schematic diagram of the multi-sensor fusion data extraction system. The system hardware uses a Raspberry Pi 4B as the host computer and Arduino and C51 microcontrollers as slave computers. Temperature sensors, laser particle size analyzers, Hall effect sensors, gas concentration sensors, pH sensors, and flow sensors are used as slave computers. The overall process is as follows: First, data acquisition: each sensor transmits raw data to the main controller (Raspberry Pi + Arduino) via SPI / I2C / UART interfaces. Next, data preprocessing: Kalman filtering is applied to analog signals such as temperature, and the timestamps of multi-sensor data are aligned using the NTP protocol or hardware interrupts. Then, feature extraction and synchronization: OpenCV is used to extract particle edge features (Canny algorithm). Next, decision-making and control output: PID control adjusts the heater power to maintain the target temperature, and LSTM predicts and dynamically optimizes the roasting time. Finally, actuator control: PWM / relay control controls the heater and motor speeds.

[0043] Therefore, the iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology of the present invention improves the iron resource recovery rate in iron tailings, reduces the flue gas generated from roasting iron tailings, reduces wastewater discharge, and reduces the use of chlorinating agents by recycling chlorinating agents, while simultaneously removing heavy metals (lead, cadmium), and the leaching residue has low toxicity. Specifically, it has the following advantages: Mechanical suspension is used instead of water suspension to reduce the impact of water on the magnetization roasting of iron tailings, and to avoid water oxidizing iron into ferric oxide at high temperatures, thus reducing the iron recovery rate.

[0044] A magnetic separator is installed between the roasting furnace outlet and the discharge port to improve the recovery rate of refined iron ore, and the iron tailings that are not magnetically separated are blown back into the roasting furnace for re-roasting.

[0045] The industrial exhaust gas emitted by the equipment (mainly acidic gases HCl and SO2 and volatile heavy metal compounds FeCl3 and PbCl2, etc.) can be separated into NaCl and Na2SO4 by physical crystallization through heated pipes after passing through the flue gas treatment chamber. After recrystallization, NaCl can be recycled as a chlorinating agent, and NaOH can be removed by forming precipitates with volatile heavy metals.

[0046] The high-shear homogenizer crushes iron tailings into particles with a diameter of less than 0.074 mm, ensuring the separation of iron tailings from chlorinating agents in the roasting furnace.

[0047] In addition, the present invention also provides an iron tailings, which is recovered by the iron tailings reprocessing and recycling equipment based on the above-mentioned mechanical suspension magnetization roasting technology.

[0048] In summary, this invention provides an iron tailings reprocessing and recovery device based on mechanical suspension magnetization roasting technology. This device innovatively replaces the traditional water-based suspension process with mechanical suspension, avoiding the reduction in iron yield caused by water acting as an oxidant at high temperatures, which would otherwise oxidize iron to iron oxide. Simultaneously, perforations are designed on the fan-shaped impeller to recover the chlorinating agent while the impeller rotates. To improve the recovery rate of refined iron ore, a monitoring and control system is designed to convert non-magnetic materials into magnetic iron ore for magnetic separation. This system reduces tailings emissions by precisely controlling the strength of the magnetism at specific times. Furthermore, the acidic flue gas from this device is neutralized in the tail gas treatment chamber, and the chlorinating agent is regenerated and recycled.

[0049] Compared to traditional recovery methods (using permanent magnets to adsorb iron tailings followed by washing with water or scrapers), a novel recovery device based on suspension magnetization roasting of iron tailings has been developed. Traditional iron tailings treatment uses water suspension to suspend the tailings. At high temperatures, water acts as an oxidant, causing iron to oxidize into iron oxide, thus reducing iron production and resulting in significant wastewater discharge. To address this problem, this invention uses mechanical suspension instead of water suspension, reducing wastewater discharge. Furthermore, traditional iron tailings recovery devices use permanent magnets in their magnetic separation equipment, with fixed magnetic strength, making timely adjustments difficult. Additionally, water or scrapers are needed to remove the magnetized iron ore, leading to significant water waste or wear on the magnetic separation equipment. This invention uses an air pump and a ring-shaped magnet with multiple magnets of varying magnetic strengths spaced circumferentially to achieve magnetic separation. Furthermore, traditional recovery devices cannot dynamically adjust factors such as temperature and magnetic field in real time; they can only pre-set the corresponding parameters. If temperature control is not timely, it may lead to incomplete reduction reaction, reduced magnetic mineral production, and decreased magnetic separation efficiency. Insufficient magnetic field control can cause three major problems: mineral loss, impurity contamination, and a surge in energy consumption, directly resulting in a 10%-30% decrease in yield. This invention achieves temperature control through sensors and adjusts the magnetic field strength at the bifurcation point by controlling the rotation angle of the annular magnet, thus effectively separating micron-sized weakly magnetic particles (such as hematite). Finally, compared with traditional devices (which directly discharge exhaust gas after preliminary treatment), this equipment also optimizes the exhaust gas treatment device, enabling the recycling of some products throughout the process and achieving the recovery of by-products.

[0050] It should be noted that, depending on the implementation needs, the various steps / components described in this invention can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0051] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An iron tailings reprocessing and recovery device based on mechanical suspension magnetization roasting technology, characterized in that, The device includes: The pretreatment grinding unit is used for screening and grinding iron tailings; A suspension magnetization roasting device, connected to the discharge port of a pretreatment grinding mechanism, includes a suspension magnetization roasting furnace and a mechanical stirring structure. The mechanical stirring structure is located inside the suspension magnetization roasting furnace and includes a spiral-shaped gap baffle impeller with a perforated structure. The gap baffle impeller is driven by a first driving mechanism and can rotate in both directions, corresponding to the roasting stirring mode and the discharge mode, respectively. In the roasting stirring mode, the first driving mechanism drives the gap baffle impeller to rotate forward, and the iron tailings are carried upward by the spiral-shaped gap baffle impeller and then poured to the bottom of the furnace body, where they come into full contact with the gas generated by the heating reaction of the chlorinating agent inside the furnace body. In the discharge mode, the first driving mechanism drives the gap baffle impeller to rotate in reverse, and the iron tailings are sent to the roasting product outlet of the suspension magnetization roasting furnace by the spiral-shaped gap baffle impeller, while the chlorinating agent remains in the suspension magnetization roasting furnace through the perforated structure of the gap baffle impeller. A magnetic separation device is connected to the roasting product outlet of a suspension magnetized roasting device and is used to separate magnetic minerals. The exhaust gas recovery and treatment device is connected to the flue gas outlet of the suspension magnetized roasting device, and includes an alkaline reaction chamber, a gas-liquid separator, and a crystallization unit. The alkaline reaction chamber is used to introduce alkaline reactants to neutralize the acidic flue gas. The gas-liquid separator is used to separate the clean gas and liquid after the neutralization reaction. The crystallization unit is used to evaporate and crystallize the liquid to separate sodium chloride crystals for reuse in the suspension magnetized roasting device.

2. The iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology according to claim 1, characterized in that, The pretreatment grinding mechanism includes: The screening mechanism is equipped with sieve plates of different aperture sizes to separate and screen small and large iron tailings particles. The high-homogeneity shearing mechanism is connected to the large particle outlet of the screening mechanism and is used to refine, grind and crush large iron tailings. A one-way valve is connected to the small particle outlet of the screening mechanism and the outlet of the high homogeneous shearing mechanism to control the unidirectional and uniform feeding of materials.

3. The iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology according to claim 2, characterized in that, The one-way valve includes a connecting flange, valve body, valve seat, valve disc, valve cover, and lifting ring; there are two connecting flanges, one connecting the valve body inlet to the small particle outlet of the screening mechanism and the outlet of the high homogeneous shearing mechanism, and the other connecting the valve body outlet to the suspension magnetization roasting device; the valve seat and valve disc are located inside the valve body and are used to control the unidirectional uniform feeding of materials; the valve cover is located on the top of the valve body, and the lifting ring is located on the top of the valve cover.

4. The iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology according to claim 1, characterized in that, The magnetic separation device includes a roasting product collection channel, an air pump, a Y-shaped structure, an annular magnet, and a second drive mechanism. The roasting product collection channel has a roasting product collection port, which is directly opposite the roasting product outlet of the suspension magnetized roasting device, for collecting roasting products. One end of the roasting product collection channel is connected to an air pump, and the other end is connected to the bottom of the Y-shaped structure, for blowing the collected roasting products to the Y-shaped structure. The two branches of the Y-shaped structure are a recovery channel and a discharge channel, respectively. The recovery channel is connected to the suspension magnetized roasting device. The annular magnet is located at the branch of the Y-shaped structure. It generates a magnetic force that attracts the iron tailings, causing the iron tailings to enter the discharge channel, while other roasting products enter the recovery channel and are recovered to the suspension magnetized roasting device. The annular magnet has multiple magnets with different magnetic field strengths arranged at intervals along its circumference. The second drive mechanism is connected to the annular magnet and drives the annular magnet to rotate and switch the magnets to adjust the magnetic field strength at the branch.

5. The iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology according to claim 1, characterized in that, The alkaline reaction chamber is a vertical cylindrical container, internally divided into upper and lower layers: The upper layer is a spray reaction chamber, used to introduce alkaline reactants to neutralize acidic flue gas; The lower layer is a sedimentation collection chamber, which has a conical bottom to collect the liquid and precipitate after the reaction.

6. The iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology according to claim 5, characterized in that, The alkaline reaction chamber is equipped with an exhaust port at the top and a slag discharge valve and a belt drive mechanism at the bottom. The slag discharge valve is equipped with upper and lower baffles and a pneumatic-hydraulic push rod. The pneumatic-hydraulic push rod controls the opening and closing of the upper and lower baffles. The belt drive mechanism discharges slag through the slag discharge valve. The conical opening at the bottom of the sedimentation collection chamber is equipped with a planetary gear stirrer to prevent clogging.

7. The iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology according to claim 1, characterized in that, The gas-liquid separator adopts a cyclone separator design with a spiral guide plate inside. The flue gas enters tangentially, the clean gas is discharged from the top, and the liquid flows out from the bottom to the crystallization unit.

8. The iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology according to claim 1, characterized in that, The crystallization unit includes an evaporator and a crystallizer; the evaporator is used to concentrate the liquid, and the crystallizer is equipped with a cooling component and a crystallization tank. The cooling component causes the concentrated liquid to crystallize in the crystallization tank and be reused in the suspension magnetization calcination device.

9. The iron tailings reprocessing and recovery equipment based on mechanical suspension magnetization roasting technology according to claim 1, characterized in that, The equipment also includes a measurement and control system, which includes: The first laser particle size analyzer is installed in the pre-treatment grinding mechanism to detect the size of iron tailings particles so that the iron tailings grinding meets the standards. The second laser particle size analyzer is installed in the suspension magnetization roasting furnace of the suspension magnetization roasting device to detect the size of iron tailings particles in order to control the roasting time; the larger the iron tailings particles, the longer the roasting time. The first temperature sensor is installed in the suspension magnetization roasting furnace of the suspension magnetization roasting device to control the roasting temperature; The second temperature sensor is installed in the evaporator of the crystallization unit of the exhaust gas recovery and treatment device to control the evaporator temperature. The Hall effect sensor, located on the annular magnet of the magnetic separator, is used to switch the magnet by controlling the rotation angle of the annular magnet according to the size of the iron tailings particles detected by the second laser particle size analyzer, so as to adjust the magnetic field strength at the bifurcation point; wherein, the larger the iron tailings particles, the stronger the magnetic field. Gas concentration sensor and pH sensor are installed in the alkaline reaction chamber of the exhaust gas recovery and treatment device to detect the concentration and pH value of acidic flue gas. If the concentration and pH value of acidic flue gas meet the standards, the exhaust port at the top of the alkaline reaction chamber will be opened. A flow sensor is installed at the bottom of the alkaline reaction chamber of the exhaust gas recovery and treatment device to detect the liquid flow rate and control the amount of alkaline reactant added.

10. An iron tailings ore, characterized in that, The iron tailings are recovered by the iron tailings reprocessing and recycling equipment based on mechanical suspension magnetization roasting technology as described in any one of claims 1 to 9.

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