Iron ore sintering intensification method based on intermittent atmosphere regulation and magnetic field optimization

Abstract

This invention relates to the field of sintering process control, and discloses a method for strengthening iron ore sintering based on intermittent atmosphere regulation and magnetic field optimization. The core of this method lies in deconstructing sintering, traditionally considered a single, continuous thermal process, into three characteristic stages based on its physicochemical changes: preheating and ignition, combustion and main reaction, and holding and cooling. For each stage, a collaborative control system integrating an intermittent injection unit and a segmented magnetic field generator is constructed to precisely intervene in the thermal regime and reaction microenvironment of the material layer, addressing the key contradictions and optimization objectives. Compared to existing NOx treatment methods, this invention reduces the NOx concentration in sintering flue gas by avoiding abnormally high temperatures in the combustion zone and achieving more uniform combustion, thus reducing pollutant emissions at the source without increasing end-of-pipe treatment costs.

Description

Technical Field

[0001] This invention relates to the field of sintering process control, and in particular to a method for strengthening iron ore sintering based on intermittent atmosphere regulation and magnetic field optimization. Background Technology

[0002] Iron ore sintering is an indispensable and crucial pre-process in modern blast furnace ironmaking. Its main purpose is to mix fine-grained iron ore powder, such as concentrate powder and rich ore powder, fluxes such as limestone and dolomite, and solid fuels such as coke powder or anthracite, in a specific ratio. After ignition, the mixture undergoes a high-temperature reaction under ventilated conditions. During this process, the mixture bed undergoes a series of complex physicochemical changes, including moisture evaporation, fuel combustion, carbonate decomposition, mineral solid-phase reactions, and partial melting of materials. Ultimately, it cools and solidifies into a porous, blocky material with sufficient strength and suitable metallurgical properties—the sinter.

[0003] As the most important iron-containing raw material in blast furnaces, the quality of sinter directly affects the smooth operation of blast furnace production, energy consumption, and pig iron quality. Ideal sinter should possess good cold strength (such as drum strength), hot properties (such as reducibility and low-temperature reducing pulverization), and a reasonable chemical composition. Its microstructure is typically expected to consist of high-strength calcium ferrite (especially acicular calcium ferrite, SFCA) as the main binder phase to achieve excellent overall performance.

[0004] However, traditional sintering processes face many challenges: uneven distribution and combustion of solid fuel in the material layer leads to local overmelting or underburning; significant uneven heat distribution in the vertical direction affects the overall quality stability; and increasing fuel consumption in pursuit of high strength will increase FeO content, impair reducibility, and increase energy consumption and carbon emissions.

[0005] In addition, the sintering process is one of the main sources of pollutant emissions from steel plants, producing sulfur dioxide, nitrogen oxides, and dust that put pressure on the environment. Although the industry has developed improved technologies such as thick material layers, fuel separation, and flue gas recirculation, there is still significant room for improvement in achieving precise control of the microstructure of minerals in the sintering process and optimizing the uniformity of the entire process.

[0006] To address these issues, several patented solutions have been developed. For example, some patents use multiple bellows to control flue gas temperature during iron ore sintering (CN202210831786.6). Additionally, some patents classify sintering fuels, perform secondary mixing, and add appropriate amounts of low-carbon alcohols to control nitrogen oxide emissions (CN202311206009.3, CN202010519298.2). Regarding sintering optimization, some patents use utilization coefficients, sintering solid fuel consumption, and residual carbon changes as evaluation criteria, or the initial low-temperature reduction pulverization index of the sintered ore, original chemical composition, and their proportions to optimize iron ore sintering methods (CN202311158994.5, CN202511463650.4). In terms of sintering evaluation, some patents use the liquid phase bonding range and liquid phase bonding strength to evaluate the liquid phase bonding effect during iron ore sintering (CN202110689251.5).

[0007] Despite some technological advancements, existing technologies still face several bottlenecks. These include poor uniformity and process controllability in solid fuel combustion, a lack of proactive methods for controlling the formation of beneficial binder phases, and rudimentary methods for regulating the process gas atmosphere. To address these shortcomings, this invention aims to provide a method and system for strengthening iron ore sintering based on intermittent atmosphere control and magnetic field optimization. Its core objective is to achieve precise control over the combustion process, heat distribution, and mineral crystallization behavior by introducing a controllable intermittent injection atmosphere coupled with a specific magnetic field environment at key stages of the sintering process. This solves the technical problems of uneven combustion, large temperature gradients, difficulty in synergistically optimizing fuel consumption and metallurgical performance, and the difficulty in proactively guiding the formation of beneficial mineral phases in traditional sintering. Ultimately, it achieves a comprehensive effect of simultaneously improving the strength and reducibility of sintered ore, improving quality uniformity, and reducing pollutant emissions while stabilizing or even reducing fuel consumption. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for strengthening iron ore sintering based on intermittent atmosphere control and magnetic field optimization.

[0009] This invention is achieved through the following technical solution:

[0010] A method for strengthening iron ore sintering based on intermittent atmosphere control and magnetic field optimization is proposed. Its core lies in deconstructing sintering, traditionally considered a single, continuous thermal process, into three characteristic stages based on its physicochemical changes: preheating and ignition, combustion and main reaction, and heat preservation and cooling. For each stage's key challenges and optimization objectives, a collaborative control system integrating intermittent injection units and segmented magnetic field generators is constructed to precisely intervene in the thermal regime and reaction microenvironment of the material layer. The intermittent injection units, located above each zone, are equipped with multiple independent spray guns capable of delivering oxygen-enriched air, water vapor, low-temperature air, or circulating flue gas. The atmosphere type, flow rate, and intermittent start-stop at a frequency of 0.2-5 Hz are controlled by a program. Segmented magnetic field generators: Distributed below each zone and above the exhaust gate, these generators consist of multiple independent electromagnetic coils. They generate a weak alternating magnetic field of 0.05-0.2T with a frequency of 10-50Hz in zone 1, a medium-intensity static magnetic field of 0.3-0.8T in zone 2, and a weak static magnetic field of 0.1-0.3T in zone 3. Online monitoring and feedback control system: Integrating an infrared thermal imager and a flue gas composition analyzer, connected to a central controller. The controller dynamically adjusts the operating parameters of the injection unit and the magnetic field device based on real-time monitoring data, forming a closed-loop control system.

[0011] The method implements the following stage of coupling control according to the sintering process:

[0012] Zone 1—Preheating and Ignition Control Zone 1: Above Zone 1, the left nozzle 1.3 and right nozzle 1.6 of Zone 1 intermittently spray oxygen-enriched air at a temperature of 50-100℃ and an oxygen concentration of 25-35% onto the material surface. This intermittent spraying promotes rapid and uniform ignition of the surface fuel while avoiding excessive cooling of the unburned material layer by the airflow. Simultaneously, a weak alternating magnetic field is applied to the magnetization zone 1.4 of Zone 1, causing microscopic vibration and rotation of the iron ore powder particles in the material layer. This effectively disrupts the tight packing between particles, increases the initial porosity of the material layer, and thus makes the airflow distribution more uniform, laying the foundation for subsequent uniform combustion.

[0013] Region 2—Main Reaction Zone Optimization and Control Zone 2: In the high-temperature reaction zone, a dynamic strategy is implemented to control the gas atmosphere and flow rate of the left nozzle 2.2 and right nozzle 2.7 in Region 2. The temperature distribution of Region 2 is detected by the infrared thermal imager detection tube 2.3. Based on the temperature distribution feedback from the central controller and the infrared thermal imager acquisition computer 2.4, oxygen-enriched air or water vapor is selectively and intermittently injected: when the local temperature is detected to be below 1150℃, a high-oxygen atmosphere is injected to enhance combustion and increase the temperature; when the local temperature is detected to be above 1250℃, the injection is switched to low-flow water vapor, which moderately moderates the combustion intensity through heat absorption and vaporization reaction to prevent over-melting. Throughout this process, a medium-intensity static magnetic field is continuously applied to the magnetization zone 2.5 of Region 2. The magnetic field acts on the forming molten liquid phase, causing the microcrystals such as iron oxides in it to align in a direction along the magnetic field. This promotes the nucleation and growth of the high-strength, high-reducibility binder phase—acicular calcium ferrite—while inhibiting the formation of the low-strength, high-FeO glass phase and the macroporous thin-walled structure, thereby optimizing the quality of the sinter from a microstructural perspective.

[0014] Zone 3—Cooling Process Control Zone 3: The left nozzle 3.2 and right nozzle 3.5 of Zone 3 inject low-temperature air or low-oxygen flue gas at 20-50℃ into the high-temperature sinter layer. Simultaneously, a weak static magnetic field is applied to the magnetization zone 3.3 of Zone 3. This combined action aims to achieve controlled cooling. The magnetic field helps reduce thermal stress during the cooling process and minimizes microcracks caused by rapid temperature gradient changes, thereby further improving the yield and cold strength of the sinter.

[0015] Control system: such as Figure 2 As shown, after ignition, the mixture enters the control zone of this system. The central controller, based on a preset program and real-time sensor data, adjusts the nozzle regulating valves of each zone and executes a specific injection mode for that stage (such as oxygen-enriched pulse injection or intermittent steam injection). Simultaneously, it triggers the intermittent cycle of the magnetic field generator in the corresponding section, accompanied by the effect of a static magnetic field throughout. This coupling of atmospheric pulses and a steady-state magnetic field enables precise management of the sintering combustion zone. Through the above technical solution, this invention combines the gas environment control capability of intermittent atmospheric injection with the directional induction capability of magnetic fields on microscopic particle behavior and crystal growth, forming a novel active intervention mode for the sintering process, improving the efficiency and control of iron ore sintering.

[0016] The positional and connection relationships of these parts are as follows:

[0017] The area 1—preheating and ignition control zone 1—includes a raw material discharge gate 1.1, a left nozzle 1.3 of area 1 equipped with a left nozzle regulating valve 1.2, a magnetization zone 1.4 located below area 1, an area 1 magnetization zone surrounded by an electrode coil 1.9, a right nozzle 1.6 of area 1 equipped with a right nozzle regulating valve 1.5, a gas detection pipe 1.8 of area 1 equipped with a gas detection regulating valve 1.7, and a discharge gate 1.10 of area 1 located below the magnetization zone 1.4.

[0018] The main reaction optimization and control zone 2 is located below the emission gate 1.10 of zone 1. The left nozzle 2.2 of zone 2 is equipped with the left nozzle regulating valve 2.1 of zone 1. The infrared thermal imager detection tube 2.3 is located below the left nozzle of zone 2. The infrared thermal imager detection tube is externally connected to the central controller and the infrared thermal imager acquisition computer 2.4. The magnetization zone 2.5 of zone 2 is located below zone 2. The magnetization zone 2.5 of zone 2 is surrounded by the electrode coil 2.10 of zone 2. The right nozzle 2.7 of zone 2 is equipped with the right nozzle regulating valve 2.6 of zone 2. The gas detection tube 2.9 of zone 2 is equipped with the gas detection regulating valve 2.8 of zone 2. The emission gate 2.11 of zone 2 is located below the magnetization zone 2.5 of zone 2.

[0019] The cooling process control zone 3 is located below the exhaust gate 2.11 of zone 2. The left nozzle 3.2 of zone 3 is equipped with the left nozzle regulating valve 3.1 of zone 3. The magnetization zone 3.3 of zone 3 is located below zone 3. The magnetization zone 3.3 of zone 3 is surrounded by the electrode coil 3.8 of zone 3. The right nozzle 3.5 of zone 3 is equipped with the right nozzle regulating valve 3.4 of zone 3. The gas detection tube 3.7 of zone 3 is equipped with the gas detection regulating valve 3.6 of zone 3.

[0020] The iron ore discharge gate 4 is located below the magnetization zone 3.3 in area 3. The iron ore sintering collection pipe 5 is located below the iron ore discharge gate 4 and is connected to the iron ore sintering collection bag 6. The tail gas pipe 7 is located to the upper right of the iron ore discharge gate. Along the right side, it is connected to the flue gas circulation pipe 9, which is equipped with the flue gas regulating valve 8. To the right of the flue gas circulation pipe 9 is the flue gas treatment system 10. After the flue gas in the flue gas circulation pipe is treated by low-temperature circulation, it returns to the right nozzle 3.5 in area 3.

[0021] Vertically, the system features intermittent spray units (containing multiple independent spray guns) above each area, and segmented magnetic field generators and sample probes for flue gas composition analyzers below. Horizontally, the spray guns and magnetic field generators in each area work together, dynamically controlling the sintering bed through specific operating modes and flow rate adjustments. All components are organically integrated into an online monitoring and feedback control system, forming a closed-loop control. Infrared thermal imagers and flue gas composition analyzers collect temperature field and flue gas composition data in real time and transmit them to a central controller. This controller compares and makes decisions based on a preset optimized process model and real-time data, generating specific control commands. These commands are output via control cables or industrial networks, acting on the spray units and magnetic field generators to comprehensively regulate the atmosphere, temperature, and micro-reaction environment of the sintering bed. Finally, the intervention effects of the spray and magnetic fields are fed back to the central controller through the monitoring system, achieving dynamic, adaptive, and refined closed-loop control of the sintering process.

[0022] How do these components work together to solve practical problems?

[0023] This invention relates to a collaborative control system for sintering machines, designed to optimize the sintering process, improve product quality, and save energy. The system integrates multiple technologies, including an infrared thermal imager, a flue gas composition analyzer, a jetting unit, and a magnetic field generator, to solve several key problems encountered during the sintering process.

[0024] The system uses an infrared thermal imager to monitor the temperature distribution across the entire material surface in real time, accurately identifying hot spots with excessively high temperatures and cold areas with low temperatures. For cold areas, oxygen-enriched air pulse jets are activated to enhance local combustion; while for overheated areas, micro-water vapor pulse jets are used to effectively suppress overheating. This successfully achieves lateral and longitudinal temperature uniformity in the material layer, thereby significantly improving sintering quality.

[0025] By utilizing static magnetic fields to optimize mineral structure—for example, applying a moderate-intensity static magnetic field to the sintering region—the system can directly influence the solidification process of the liquid phase, inducing the formation of high-strength, highly reducible needle-like calcium ferrite (SFCA). Simultaneously, the combustion atmosphere is regulated through a jetting unit to maintain the temperature within an optimal range (approximately 1150-1250℃), creating ideal conditions for SFCA formation. This microstructure optimization not only improves product strength but also reduces FeO content, enhances reducibility, and reduces energy consumption, achieving multiple objectives.

[0026] A weak alternating magnetic field and oxygen-enriched pulse jets are simultaneously activated in the ignition zone. Under the influence of the magnetic field, the micro-particles of the iron ore powder vibrate, increasing their porosity; at the same time, the oxygen-enriched airflow provides a uniform ignition environment. The combination of these two factors fundamentally improves the permeability of the material layer, laying a solid foundation for subsequent uniform sintering.

[0027] The system employs intelligent closed-loop control to address changes in the sintering process. When abnormal combustion temperatures are detected due to fluctuations in raw materials, infrared thermal imagers and flue gas analyzers promptly capture these changes. The central controller then responds quickly, automatically adjusting the flow rate, duration, and magnetic field strength of the injection medium in each zone to effectively compensate for raw material fluctuations. This mechanism significantly reduces reliance on human experience, making the production process more stable and intelligent.

[0028] The system monitors temperature using an infrared thermal imager. Once a localized high temperature is detected, the controller immediately instructs the injection unit to spray water vapor onto that point for cooling. This precise temperature control not only effectively suppresses NOx formation but also reduces emission costs.

[0029] In summary, by combining the synergistic effect of jetting and magnetic fields, along with the organic integration of monitoring and execution, precise control of the sintering process was achieved. This not only improves production efficiency but also enhances the quality of the final product, demonstrating broad application prospects.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. Compared with existing sintering methods, this system significantly improves the uniformity of temperature distribution throughout the sintering layer, reduces the maximum temperature difference in the vertical direction of the combustion zone, and effectively eliminates the phenomenon of over-melting in the upper layer and under-burning in the lower layer, thereby improving the stability of sinter quality and yield.

[0032] 2. Compared with existing sintering methods, this method can further reduce solid fuel consumption while maintaining or even improving the strength of sintered ore, and at the same time reduce the FeO content in sintered ore, thus achieving the dual goals of energy saving and improving metallurgical performance.

[0033] 3. Compared to existing technologies that rely on adjusting alkalinity and temperature to indirectly influence mineral structure, the magnetic field drives the directional growth of iron oxide crystal nuclei in the molten liquid phase, significantly increasing the content of beneficial binder phases, such as acicular calcium ferrite. This directly leads to an increase in the drum index (strength index) of the sinter, while its low-temperature reduction pulverization index and degree of reduction are also improved.

[0034] 4. Compared with traditional technology, the micro-vibration effect of alternating magnetic field increases the initial porosity of the material layer, effectively reduces the material layer resistance, improves the permeability in the initial stage of sintering, lays the foundation for subsequent uniform combustion and rapid sintering, and can improve the sintering speed.

[0035] 5. Compared to existing technologies, this system achieves refined operation of the sintering process. It can automatically compensate for fluctuations in raw material composition, moisture, and particle size, maintaining stable process conditions and reducing quality fluctuations caused by manual intervention and reliance on experience. This significantly improves the stability and controllability of the production process.

[0036] 6. Compared with existing NOx treatment methods, by avoiding abnormally high temperatures in the combustion zone and combining it with more uniform combustion, the NOx concentration in sintering flue gas can be reduced, thereby reducing pollutant emissions at the source without increasing end-of-pipe treatment costs. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the present invention.

[0038] Figure 2 This is a flowchart of the online monitoring and feedback control system of the present invention.

[0039] Labeling Explanation: 1 represents Zone 1—Preheating and Ignition Control Zone; 1.1 represents the raw material discharge valve; 1.2 represents the Zone 1 left nozzle regulating valve; 1.3 represents the Zone 1 left nozzle; 1.4 represents Zone 1 magnetization zone 1; 1.5 represents the Zone 1 right nozzle regulating valve; 1.6 represents the Zone 1 right nozzle; 1.7 represents the Zone 1 gas detection regulating valve; 1.8 represents the Zone 1 gas detection tube; 1.9 represents the Zone 1 electrode coil; 1.10 represents the Zone 1 discharge valve; 2 represents Zone 2—Main Reaction Optimization Control Zone; 2.1 represents the Zone 2 left nozzle regulating valve; 2.2 represents the Zone 2 left nozzle; 2.3 represents the infrared thermal imager detection tube; 2.4 represents the central controller and infrared thermal imager acquisition computer; 2.5 represents the Zone 2 magnetization zone; 2.6 represents the Zone 2 right nozzle regulating valve. 2.7 is the right nozzle of Zone 2, 2.8 is the gas detection and regulating valve of Zone 2, 2.9 is the gas detection tube of Zone 2, 2.10 is the electrode coil of Zone 2, 2.11 is the exhaust gate of Zone 2, 3 is Zone 3—Cooling process control zone, 3.1 is the regulating valve of the left nozzle of Zone 3, 3.2 is the left nozzle of Zone 3, 3.3 is the magnetization zone of Zone 3, 3.4 is the regulating valve of the right nozzle of Zone 3, 3.5 is the right nozzle of Zone 3, 3.6 is the gas detection and regulating valve of Zone 3, 3.7 is the gas detection tube of Zone 3, 3.8 is the electrode coil of Zone 3, 4 is the iron ore exhaust gate, 5 is the iron ore sintering collection pipe, 6 is the iron ore sintering collection bag, 7 is the tail gas pipe, 8 is the flue gas regulating valve, 9 is the flue gas recirculation pipe, and 10 is the flue gas treatment system. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Please see Figure 1 The present invention provides a technical solution:

[0042] The following example uses a steel plant with an effective sintering area of ​​260m². 2 Taking a belt sintering machine as an example, the specific implementation process of the present invention will be described in detail.

[0043] The collaborative control system described in this invention is installed at corresponding positions above and below the trolley after the ignition furnace of the sintering machine and before the sinter crusher. The system completes the connection and debugging of the circuit, gas circuit and data lines.

[0044] The central controller and infrared thermal imager acquisition computer 2.4 preset core process parameters: In Zone 1—Preheating and Ignition Control Zone 1, the blowing medium is oxygen-enriched air (oxygen concentration 30%, temperature 80℃), and the blowing frequency is set to 1Hz (i.e., intermittent start-stop, 0.5 seconds on and 0.5 seconds off per cycle). The magnetic field parameter is set to an alternating magnetic field of 0.1T with a frequency of 30Hz. In Zone 2—Main Reaction Optimization Control Zone 2, the temperature control threshold is set as follows: when the infrared thermal imager detection tube 2.3 detects a local temperature below 1150℃, oxygen-enriched air blowing is triggered; when it exceeds 1250℃, low-pressure steam blowing is triggered. The magnetic field parameter is set to a static magnetic field of 0.5T.

[0045] The injection medium in Zone 3—Cooling Process Control Zone 3—is treated low-temperature circulating flue gas (temperature approximately 30°C, oxygen content <15%). The magnetic field parameter is set to a static magnetic field of 0.2T.

[0046] The iron ore mixture (containing iron raw materials, flux, solid fuel, etc.) enters Zone 1—Preheating and Ignition Control Zone 1—through the raw material discharge gate 1.1. At this time, the left nozzle 1.3 and right nozzle 1.6 of Zone 1 begin to pulse-blow oxygen-enriched air (30% oxygen concentration) at 80°C onto the material surface at a preset frequency of 1Hz. This intermittent airflow provides an oxygen-enriched environment for the continuous and uniform combustion of the surface fuel and avoids the cooling of the unburned fuel in the lower layer by continuous strong winds. Simultaneously, the electrode coil 1.9 generator in Zone 1 below the material layer is activated, generating an alternating magnetic field of 0.1T and 30Hz, i.e., the electromagnetic zone 1.4 of Zone 1. The magnetic force causes the iron ore powder particles to vibrate and rotate microscopically, effectively breaking up the tight packing caused by gravity compaction, increasing the initial porosity of the material layer by about 8%, and significantly improving the air permeability of the upper part of the material layer.

[0047] The reactants, after preheating and ignition, enter Zone 2 through Zone 1 exhaust gate 1.10. This is the core area of ​​the high-temperature sintering reaction. The infrared thermal imager detection tube 2.3 continuously scans the reactants, generates a temperature field distribution map in real time, and transmits it to the central controller and the infrared thermal imager acquisition computer 2.4.

[0048] Example 1: Addressing a localized low-temperature point. The central controller and infrared thermal imager, along with computer 2.4, detected a point with an area of ​​approximately 0.5 m² located 1.5 m to the right of the center of area 2. 2 The low-temperature zone (average temperature 1120℃) was immediately controlled by the central controller and the infrared thermal imager computer 2.4, which instructed the right nozzle 2.7 of this zone to perform targeted, intermittent oxygen-enriched air injection. The oxygen-enriched airflow enhanced local combustion, and after about 60 seconds, the temperature in this zone rose and stabilized within a suitable range of 1180-1200℃.

[0049] Example 2: Suppressing Localized Hot Spots. Simultaneously, the infrared thermal imager detection tube 2.3 detected a sudden temperature rise to 1270℃ at a certain point in the center. The central controller and the infrared thermal imager acquisition computer 2.4 quickly switched the spraying medium of the left nozzle 2.2 and right nozzle 2.7 in area 2 to low-pressure steam and performed pulsed spraying. The steam absorbed heat and vaporized in the high-temperature material layer, effectively absorbing excess heat, causing the temperature at that point to drop back to approximately 1230℃ within 40 seconds.

[0050] Furthermore, the static magnetic field of 0.5T in the magnetized region of region 2 is continuously applied by the electrode coil 2.10 in region 2. This magnetic field causes the iron oxide microcrystals in the high-temperature molten liquid phase to align oriented along the magnetic field lines, creating favorable conditions for the nucleation and preferential growth of needle-shaped calcium ferrite (SFCA).

[0051] The sintered ore cake, having completed the high-temperature reaction, enters Zone 3—the cooling process control zone—through the discharge gate 2.11 in Zone 2. At this time, the right nozzle 3.5 in Zone 3 injects low-temperature circulating flue gas at 30°C into the red-hot sintered ore layer for controlled cooling. Simultaneously, the weak static magnetic field (0.2T) in Zone 3 begins operation. The presence of the magnetic field helps reduce the internal thermal stress of the sintered ore during the cooling process, minimizing microcracks caused by the rapid temperature gradient.

[0052] Example 3: To suppress excessively high temperatures in sintered ore, after the discharge gate 2.11 in Zone 2 is opened, the central controller and the infrared thermal imager acquisition computer 2.4 provide feedback based on the specific temperature of the discharge gate 2.11 in Zone 2 to take further action. If the temperature distribution is too high, exceeding 500℃, the left nozzle 3.2 in Zone 3 is controlled, instructing the left nozzle in Zone 3 to inject a certain amount of water vapor into the cooling process control zone of Zone 3. The specific workload is further determined based on the algorithm of historical operating data to ensure that the circulating flue gas can reduce the sintered iron ore to the set temperature.

[0053] The effects of all the above-mentioned control actions will be reflected in the changes in the material bed temperature field and flue gas composition in real time. For example, when Zone 2 enhances oxygen enrichment in the cold zone, the O2 concentration in the flue gas of the wind box below this zone will decrease and the CO2 concentration will increase. The gas in Zone 2 passes through the Zone 2 gas detection tube and the flue gas composition analyzer to feed this change data back to the central controller and the infrared thermal imager acquisition computer 2.4, which is used to verify the control effect and fine-tune subsequent instructions.

[0054] Throughout the process, the central controller and the infrared thermal imager continuously compare the preset model with the real-time monitoring data, dynamically adjust the blowing and magnetic field parameters of each area, forming a continuous optimization closed loop to ensure that the sintering process is always carried out under ideal working conditions.

[0055] After the aforementioned refined adjustments, the produced sinter, as tested, showed that compared to products from the same period using traditional sintering processes, the drum strength of the sinter increased by approximately 2%, the FeO content decreased by approximately 1.5%, and the reducibility was improved, all while solid fuel consumption was reduced by approximately 3.5%. Simultaneously, the NOx emission concentration in the sintering machine exhaust gas decreased by more than 15%, achieving a comprehensive effect of energy saving, quality improvement, consumption reduction, and emission reduction.

[0056] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for strengthening iron ore sintering based on intermittent atmosphere control and magnetic field optimization, characterized in that, The sintering process is divided into three characteristic stages: preheating and ignition, combustion and main reaction, and holding and cooling. Coupled control is implemented for each stage. During the preheating and ignition stage, oxygen-rich air is intermittently sprayed onto the surface of the sintering material layer, while a weak alternating magnetic field is applied. During the combustion and main reaction stages, based on real-time monitored temperature field data, oxygen-rich air or water vapor is selectively and intermittently injected into local areas of the sintering material layer to regulate the temperature, while a medium-intensity static magnetic field is applied. During the heat preservation and cooling stages, low-temperature gas is injected into the sintered ore layer for cooling, while a weak static magnetic field is applied.

2. The method according to claim 1, characterized in that, During the preheating and ignition stage, the oxygen concentration of the intermittently sprayed oxygen-enriched air is 25%-35%, the temperature is 50-100℃, and the spraying frequency is 0.2-5Hz; the magnetic induction intensity of the weak alternating magnetic field is 0.05-0.2T, and the frequency is 10-50Hz.

3. The method according to claim 1, characterized in that, During the combustion and main reaction stage, when the temperature in a local area is detected to be below 1150°C, oxygen-enriched air is injected to enhance combustion; when the temperature in a local area is detected to be above 1250°C, water vapor is injected to moderate the combustion intensity; the magnetic induction intensity of the medium-intensity static magnetic field is 0.3-0.8T.

4. The method according to claim 1, characterized in that, During the heat preservation and cooling stage, the low-temperature gas injected is air at a temperature of 20-50℃ or circulating flue gas with an oxygen content of less than 15%; the magnetic induction intensity of the weak static magnetic field is 0.1-0.3T.

5. The method according to any one of claims 1 to 4, characterized in that, The temperature distribution of the sintering material layer is monitored in real time by an infrared thermal imager, and the composition of the flue gas is monitored by a flue gas composition analyzer. The monitoring data is fed back to the central controller, which dynamically adjusts the injection parameters and magnetic field parameters at each stage to form a closed-loop control.

6. An iron ore sintering strengthening system for implementing the method according to any one of claims 1-5, characterized in that, Including those arranged sequentially along the direction of travel of the sintering trolley: The system includes a preheating and ignition control zone, with a nozzle above it for intermittently injecting oxygen-enriched air and a magnetization zone 1 below it for generating a weak alternating magnetic field; a main reaction optimization control zone, with a nozzle above it for selectively and intermittently injecting oxygen-enriched air or water vapor and an infrared thermal imager detection tube, and a magnetization zone 2 below it for generating a medium-intensity static magnetic field; a cooling process control zone, with a nozzle above it for injecting low-temperature gas and a magnetization zone 3 below it for generating a weak static magnetic field; and a central controller connected to the infrared thermal imager detection tube and the flue gas composition analyzer, the central controller being connected to the regulating valves of each nozzle and the control terminals of each magnetization zone.

7. The system according to claim 6, characterized in that, The magnetization regions 1, 2, and 3 are generated by the surrounding electrode coils of region 1, region 2, and region 3, respectively.

8. The system according to claim 6, characterized in that, It also includes a flue gas recirculation pipeline, one end of which is connected to the tail gas pipe at the end of the system and the other end is connected to the nozzle of the cooling process control zone, for sending part of the recirculated flue gas after being treated by the flue gas treatment system back to the cooling process control zone.

9. The system according to claim 6, characterized in that, Each control zone is equipped with a discharge gate for the sequential transfer of materials; the final sintered product falls into the iron ore sintering collection pipe and collection bag through the iron ore discharge gate.

10. The system according to claim 6, characterized in that, The central controller is configured to: receive real-time data from the infrared thermal imager and the flue gas composition analyzer; generate instructions and output them to the regulating valves of each nozzle according to the preset process model and control threshold to control the type, flow rate and start / stop frequency of the sprayed medium; and generate instructions and output them to each electrode coil to control the magnetic field strength and type of the corresponding magnetization zone.

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