Sulfur-containing ore tunnel type drying process with spontaneous combustion prevention function

Abstract

The invention provides a sulfur-containing ore tunnel type drying process with a spontaneous combustion prevention function, and belongs to the technical field of ore drying, and the sulfur-containing ore tunnel type drying process is operated according to the following method: when the concentration of sulfur dioxide in a drying chamber is lower than a first set threshold value, a conveying belt is controlled to directionally convey sulfur-containing ore at a normal speed; when the concentration of sulfur dioxide in the drying chamber is larger than a first set threshold value and smaller than a second set threshold value, the conveying speed of the conveying belt is increased; when the concentration of sulfur dioxide in the drying chamber is larger than a second set threshold value, the telescopic interception assembly is controlled to stretch out, and the speed of the conveying belt is controlled to be increased to the maximum after the telescopic interception assembly stretches out. The method avoids further spontaneous combustion of ore, inhibits oxidation reaction, avoids massive leakage of sulfur dioxide, avoids personnel poisoning accidents, and fundamentally intervenes in spontaneous combustion accidents.

Description

Technical Field

[0001] This invention relates to the field of ore drying technology, and in particular to a tunnel drying process for sulfur-containing ores with anti-self-ignition function. Background Technology

[0002] The tunnel drying process is a continuous operation. Its core structure includes a drying chamber, a hot air system, and a control system. The drying chamber consists of multiple parallel tunnels, on which sulfur-containing ore is placed on a conveyor belt. Hot air is generated by fans and heaters, flowing through the tunnels and contacting the ore. Heat is transferred to the ore through convection and radiation, while simultaneously removing moisture from the ore's surface. The drying process is divided into a preheating stage, a constant-rate drying stage, and a decreasing-rate drying stage. The control system achieves precise control by adjusting temperature, humidity, and airflow, ensuring a closed-loop circulation of hot air within the tunnels. The material is conveyed by the conveyor belt; opening the two closed doors allows a batch of dry material to exit, removing some moisture, while a batch of wet material enters, replenishing some air. The tunnel length can reach 30-40 meters.

[0003] Due to the natural characteristics of pyrite, the drying process involves three stages: physical adsorption, chemical adsorption, and chemical combustion. In the chemical adsorption stage, oxygen molecules are physically adsorbed onto the pyrite surface, resulting in weak interaction between the ore and oxygen and minimal heat release. As the temperature rises, the chemisorption stage begins, where oxygen molecules chemically adsorb onto active sites on the pyrite surface, initiating an oxidation reaction and releasing heat. When the temperature reaches a certain critical value, the chemical reaction stage commences, where pyrite undergoes a violent oxidation reaction with oxygen, releasing a large amount of heat and ultimately leading to spontaneous combustion and the release of large amounts of toxic gases. Current drying processes do not include preventative measures against spontaneous combustion of pyrite. The reaction equation for the spontaneous combustion of pyrite is as follows: FeS2 + 2O2 → FeSO4 + SO2 (drying environment).

[0004] Most current tunnel dryers are open-circuit, allowing fresh air to enter on one side and humid, high-temperature gas to exit on the other. They lack a trace sulfur dioxide detection device, making it impossible to detect the release of sulfur dioxide in the early stages of the oxidation reaction (a warning signal for spontaneous combustion). Furthermore, they lack active intervention measures for spontaneous combustion, which means that spontaneous combustion cannot be quickly suppressed after it occurs, leading to a large-scale leakage of sulfur dioxide and ultimately causing major safety accidents such as personnel poisoning. Summary of the Invention

[0005] This invention aims to provide an automatic regulating tunnel dryer for sulfur-containing ores with anti-spontaneous combustion function, overcoming the shortcomings of existing technologies through the following means: 1. Employing a closed-loop drying process, the humid, high-temperature flue gas exiting the dryer is dusted and the raw material is preheated. Furthermore, the flue gas is dehumidified before re-entering the drying chamber, ensuring the mass transfer driving force during the drying process. 2. A high-precision real-time sulfur dioxide detection device monitors the sulfur dioxide content in the water vapor discharged from the tunnel (safe threshold ≤0.3% and spontaneous combustion threshold ≤0.5%), serving as the basis for judging the drying effect and whether spontaneous combustion of the ore will occur. If spontaneous combustion occurs, the diversion baffle is opened to control the ore to fall into the nitrogen protection chamber below, ensuring safety. 3. Combining the fluctuating characteristics of the sulfur and moisture content of the raw material, the drying process is adaptively controlled by dynamically adjusting the ore residence time (adjusting the conveyor belt speed) and the drying temperature difference, ensuring optimal drying results.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] A tunnel drying process for sulfur-containing ores with anti-self-ignition function utilizes tunnel drying equipment with anti-self-ignition function. The tunnel drying equipment includes a drying chamber, a conveyor belt passing through the bottom of the drying chamber, and a protective chamber located below the end of the conveyor belt. The protective chamber includes a retractable telescopic interception component. A detector for detecting sulfur dioxide concentration is also installed inside the drying chamber. The process operates as follows: first, sulfur-containing ore is placed on the upper surface of the conveyor belt. The conveyor belt directionally transports the sulfur-containing ore from the inlet to the outlet of the drying chamber, achieving continuous drying of the sulfur-containing ore during the transport process. The detector continuously monitors the sulfur dioxide concentration inside the drying chamber. The concentration of sulfur; the detector is electrically connected to the conveyor belt; the detector has a first set threshold and a second set threshold; when the sulfur dioxide concentration in the drying chamber is lower than the first set threshold, the conveyor belt is controlled to transport the sulfur-containing ore in a directional manner at a normal speed; when the sulfur dioxide concentration in the drying chamber is greater than the first set threshold and less than the second set threshold, the conveyor belt speed is increased; when the sulfur dioxide concentration in the drying chamber is greater than the second set threshold, the telescopic interception component is controlled to extend outward, and after the telescopic interception component extends, the conveyor belt speed is controlled to increase to the maximum, and the sulfur-containing ore slides down into the protective chamber through the telescopic interception component for centralized storage, and protective gas is pumped into the protective chamber to encapsulate the sulfur-containing ore.

[0008] Preferably, the conveyor belt has multiple steps, including a third conveyor body and a second conveyor body located inside the drying chamber, and a first conveyor body located outside the drying chamber. The second conveyor body is located between the third conveyor body and the first conveyor body. The protective chamber is located at a predetermined position at the lower end of the second conveyor body. The telescopic interception component is arranged at an angle near the first conveyor body. When the sulfur dioxide concentration inside the drying chamber is greater than a second set threshold, the telescopic interception component is controlled to extend outward. After extending, the telescopic interception component is located between the first conveyor body and the second conveyor body to intercept the sulfur-containing ore.

[0009] Preferably, the horizontal projection of the side of the second conveying body away from the telescopic interception component is located within the horizontal projection of the protective chamber. At least two detectors are provided. The first detector is opposite to the second conveying body, and the second detector is opposite to the third conveying body. Based on the different concentrations of sulfur dioxide detected by the two detectors, the second and third conveying bodies are controlled to transport the sulfur-containing ore clockwise or counterclockwise, or paused and then clockwise.

[0010] When both the first and second detectors detect sulfur dioxide concentrations exceeding the second set threshold, the conveyor bodies 3 and 2 are controlled to rotate clockwise. Sulfur ore on the surface of conveyor body 3 is directly transferred to the surface of conveyor body 2, and then deposited into the protective chamber via a telescopic interception component. When both detectors detect sulfur dioxide concentrations exceeding the second set threshold and the second detector detects concentrations below the second set threshold, both conveyor bodies 2 and 3 are controlled to rotate clockwise, with conveyor body 2 having a higher conveying speed than conveyor body 3. The conveying rate is controlled so that the sulfur-containing ore on the surface of the conveying body two is delivered into the protective chamber through the telescopic interception component. When the first detector detects that the sulfur dioxide concentration is lower than the second set threshold and the second detector detects that the sulfur dioxide concentration is higher than the second set threshold, the conveying body three is first controlled to stop conveying, and the conveying speed of the conveying body two is increased to the maximum. After the sulfur-containing ore on the surface of the conveying body two is delivered, the conveying body three is controlled to rotate clockwise at the maximum speed, and the conveying body two is controlled to rotate counterclockwise at the maximum speed. The sulfur-containing ore on the surface of the conveying body three is delivered directly into the protective chamber after passing through the left side surface of the conveying body two.

[0011] Preferably, the protective bin includes a bin body, with a hopper located inside the upper part of the bin body. A sealing component is provided at the bottom of the hopper. During the feeding process of sulfur-containing ore, the ore passes through the sealing component and enters the bottom of the bin body. After the sulfur-containing ore is fed, the sealing component is controlled to move upward and fit against the bottom of the hopper to achieve relative closure.

[0012] Preferably, the enclosure assembly includes an enclosure positioning plate fixedly connected to the bottom of the hopper, an enclosure drive shaft rotatably connected to the inner wall of the enclosure positioning plate, an enclosure main plate fixed to the side wall of the enclosure drive shaft, a discharge port at the bottom of the hopper, and the size of the enclosure main plate being larger than the size of the discharge port.

[0013] Preferably, the side wall of the sealed main board is provided with an air jet opening, the outer side of the sealed positioning plate is provided with an air duct communicating with the air jet opening, a rotary valve is provided between the air duct and the sealed positioning plate and connected in series in the air duct, and the rotary valve is connected to the sealed drive shaft.

[0014] Preferably, an upper sealing plate is slidably connected to the upper end of the hopper body, and a linkage component is provided between the upper sealing plate and the second conveying body, so as to control the upper sealing plate to slide to different positions through the linkage component.

[0015] Preferably, the linkage component includes a linkage positioning frame located on the outer side, a positioning frame rotatably connected to the inner wall of the linkage positioning frame, a first linkage wheel and a second linkage wheel that abut against each other rotatably connected to the inner wall of the positioning frame, and a drive motor for driving the positioning frame to deflect is provided on the outer side of the linkage positioning frame.

[0016] Preferably, the first set threshold is 0.3% and the second set threshold is 0.5%.

[0017] Preferably, a feeding hopper is provided at the inlet end of the drying chamber, and a serpentine heat exchange coil is provided on the outside of the feeding hopper. The coil is connected to the drying chamber through a flow guiding heat exchange component to form an airflow circulation.

[0018] The beneficial effects of this invention are as follows:

[0019] By real-time detection and linkage control of sulfur dioxide, intervention can be initiated before spontaneous combustion occurs. Once the concentration exceeds the upper limit of spontaneous combustion concentration, the spontaneously combusting ore is immediately introduced into the nitrogen protection chamber to prevent further spontaneous combustion of the ore, inhibit oxidation reaction, prevent large-scale leakage of sulfur dioxide, and eliminate personnel poisoning accidents, thus fundamentally intervening in spontaneous combustion accidents. Moreover, it can adapt to raw material fluctuations. Even if the sulfur content and moisture content of the raw materials fluctuate, the drying parameters can be matched accordingly, achieving both sufficient drying and low energy consumption at the same time. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of another embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the structure of multiple conveying bodies and protective chambers of the present invention.

[0023] Figure 4 For the present invention Figure 3 A schematic diagram of the main structure.

[0024] Figure 5 For the present invention Figure 4 A schematic diagram of the AA-direction cross-section structure.

[0025] Figure 6 For the present invention Figure 4 Schematic diagram of the BB-direction cross-section structure.

[0026] Figure 7 For the present invention Figure 3 A side view structural diagram.

[0027] Figure 8 For the present invention Figure 7 A magnified structural diagram at point C.

[0028] Figure 9 For the present invention Figure 8 A magnified structural diagram at point D.

[0029] In the diagram: 100, conveyor belt; 110, conveyor body one; 120, conveyor body two; 130, conveyor body three; 200, protective bin; 210, bin body; 220, sealing assembly; 211, sealing positioning plate; 222, sealing drive shaft; 223, sealing main board; 224, rotary valve; 225, ventilation pipe; 230, hopper; 231, discharge port; 240, upper sealing plate; 300, drying chamber; 310, drying shell; 320, heating assembly; 330, circulating fan; 340, dividing platform; 400, telescopic interception assembly; 500, discharge bin; 600, flow guiding heat exchange assembly; 700, linkage assembly; 710, linkage positioning frame; 720, first linkage wheel; 730, second linkage wheel. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] See attached document Figure 1 - Appendix Figure 9 The sulfur-containing ore tunnel drying process with anti-self-ignition function uses tunnel drying equipment with anti-self-ignition function. The tunnel drying equipment includes a drying chamber 300 and a conveyor belt 100 passing through the bottom of the drying chamber 300. The inlet end of the drying chamber 300 is provided with a feeding hopper 500. During the drying process of sulfur-containing ore, the sulfur-containing ore in the feeding hopper 500 is put onto the upper surface of the conveyor belt 100. The conveyor belt 100 drives the sulfur-containing ore to move directionally into the drying chamber 300 for continuous drying.

[0032] The drying chamber 300 includes a drying shell 310. A dividing platform 340 is provided inside the drying shell 310 to divide the drying shell 310 into upper and lower parts. A circulating fan 330 and a heating component 320 are provided at the upper end of the dividing platform 340. The airflow inside the drying shell 310 is controlled by the circulating fan 330 to achieve continuous drying of sulfur-containing ore.

[0033] A serpentine heat exchange coil is installed outside the feeding hopper 500. The coil is connected to the drying chamber 300 through a flow-guiding heat exchange assembly 600 to form an airflow circulation. The flow-guiding heat exchange assembly 600 includes two ducts and two sets of fans. The two ducts are arranged at intervals on one side of the inlet end of the drying chamber 300, which can preheat the material with high-temperature gas drawn out of the drying chamber by the external fans. The high-temperature humid gas enters the coil in the feeding hopper through the fans and indirectly contacts and preheats the material, improving heat utilization efficiency.

[0034] It also includes a protective chamber 200, which is located below the end of the conveyor belt 100. The protective chamber 200 includes a retractable telescopic interception component 400. The drying chamber 300 is also equipped with a detector for detecting sulfur dioxide concentration. The detector can detect the concentration of sulfur dioxide at a predetermined location in the drying chamber 300 in real time to determine whether the concentration of sulfur dioxide exceeds a set threshold. The telescopic interception component 400 can intercept the normally conveyed sulfur-containing ore material, change the movement trajectory of the sulfur-containing ore, and allow the sulfur-containing ore to enter the protective chamber 200 to isolate the gas from the sulfur-containing ore, prevent excessive sulfur dioxide from overflowing, and achieve isolation and protection of the sulfur-containing ore.

[0035] The technical solution of this application operates as follows: First, sulfur-containing ore is placed on the upper surface of the conveyor belt 100. The conveyor belt 100 directionally transports the sulfur-containing ore from the inlet end of the drying chamber 300 to the outlet end, thereby achieving continuous drying of the sulfur-containing ore during the transport process.

[0036] The concentration of sulfur dioxide in the drying chamber 300 is continuously monitored using a detector; the detector is electrically connected to the conveyor belt 100; the detector has a first set threshold and a second set threshold; when the concentration of sulfur dioxide in the drying chamber 300 is lower than the first set threshold, the conveyor belt 100 is controlled to transport the sulfur-containing ore in a directional manner at a normal speed. At this time, less sulfur dioxide is generated, and within the normal concentration range, the sulfur-containing ore is in a normal drying state. It is only necessary to control the conveyor belt 100 to transport the sulfur-containing ore in a directional manner at a normal speed.

[0037] When the sulfur dioxide concentration in the drying chamber 300 is greater than the first set threshold and less than the second set threshold, the conveying speed of the conveyor belt 100 is increased. At this time, the sulfur-containing ore dries faster, and the amount of sulfur dioxide generated gradually increases during this process. By increasing the conveying speed of the conveyor belt 100, the drying time of the sulfur-containing ore in the drying chamber 300 is shortened, and excessive subsequent generation of sulfur dioxide is avoided.

[0038] When the sulfur dioxide concentration in the drying chamber 300 exceeds the second set threshold, the telescopic interception component 400 is extended outward. After the telescopic interception component 400 extends, the conveyor belt 100 speed is increased to the maximum. The sulfur-containing ore slides through the telescopic interception component 400 into the protective chamber 200 for centralized storage. Protective gas is pumped into the protective chamber 200 to encapsulate the sulfur-containing ore. At this point, the sulfur-containing ore is over-dried, entering the chemical reaction stage, producing a large amount of sulfur dioxide. The sulfur-containing ore also generates a large amount of heat and is about to spontaneously combust. The conveyor belt 100 speed is increased to the maximum, and the telescopic interception component 400 intercepts the sulfur-containing ore at the end of the conveyor belt 100 and guides it into the protective chamber 200 for isolation and protection. This separates the sulfur-containing ore from the sulfur-containing ore that is subsequently dried normally, ensuring that the sulfur-containing ore is dried normally as a whole, while preventing the sulfur-containing ore that is about to spontaneously combust from being exposed to the environment and continuously generating excessive sulfur dioxide. This avoids pollution of the surrounding working environment and also prevents spontaneous combustion, ensuring the safe operation of the drying process.

[0039] The protective gas pumped into the protective chamber 200 needs to isolate oxygen to prevent the continuous chemical reaction from generating a large amount of heat and sulfur dioxide gas. Common protective isolation gases such as nitrogen can be selected.

[0040] Furthermore, the conveyor belt 100 has multiple steps, including a third conveyor body 130 and a second conveyor body 120 located inside the drying chamber 300, and a first conveyor body 110 located outside the drying chamber 300. The second conveyor body 120 is located between the third conveyor body 130 and the first conveyor body 110. The ore is directionally conveyed along the third conveyor body 130, the second conveyor body 120, and the first conveyor body 110. At each step, the sulfur-containing ore falls onto the belt of the lower conveyor body under the action of gravity.

[0041] The protective chamber 200 is located at a predetermined position at the lower end of the conveying body 2 120. The telescopic interception component 400 is located on the side close to the conveying body 1 110 and is arranged at an angle. When the sulfur dioxide concentration in the drying chamber 300 is greater than the second set threshold, the telescopic interception component 400 is controlled to extend outward. After extending, the telescopic interception component 400 is located between the conveying body 1 110 and the conveying body 2 120 to intercept the sulfur-containing ore. At this time, the sulfur-containing ore that generates a large amount of sulfur dioxide passes through the conveying body 3 130, the conveying body 2 120, and the telescopic interception component 400 and finally enters the protective chamber 200 for centralized storage. The length of the conveying body 2 120 is smaller than that of the conveying body 3 130. After the sulfur-containing ore that is about to spontaneously combust on the surface of the conveying body 3 130 is discharged, the conveying body 3 130 can be controlled to stop rotating. The conveying body 2 120 continues to rotate to discharge the sulfur-containing ore that is about to spontaneously combust into the protective chamber 200. After that, the conveying body 3 130 is controlled to rotate in a directional manner to achieve normal drying and conveying of the remaining sulfur-containing ore.

[0042] Through the above structural design, the sulfur-containing ore in different locations can be independently transported and controlled, realizing the separate transport of sulfur-containing ore with different degrees of dryness. This not only allows for the rapid transport of sulfur-containing ore that is about to spontaneously combust to the protective chamber 200 for isolation and protection, but also increases the drying time of sulfur-containing ore that is not yet fully dried, ensuring that the sulfur-containing ore is dried to the predetermined degree to meet the processing needs of subsequent processes.

[0043] Furthermore, the horizontal projection of the side of the conveying body 2 120 away from the telescopic interception component 400 is located within the horizontal projection of the protective chamber 200, meaning that regardless of whether the conveying body 2 120 rotates clockwise or counterclockwise, it can deliver sulfur-containing ore into the protective chamber 200; according to the appendix Figure 4 When rotated clockwise as shown, the telescopic interception component 400 extends, and the sulfur-containing ore on the surface of the conveying body 120 is released into the protective chamber 200 through the telescopic interception component 400, according to the attached... Figure 4 When the conveyor rotates counterclockwise as shown, the sulfur-containing ore on the surface of the conveyor body 120 falls directly into the protective chamber 200 for isolation and protection.

[0044] Furthermore, at least two detectors are provided. The first detector is opposite to the second conveyor body 120, and the second detector is opposite to the third conveyor body 130. Through the above structural design, the concentration of sulfur dioxide on the sulfur-containing ore on the surface of different conveyor bodies can be detected to determine the dryness of the sulfur-containing ore on the surfaces of the second conveyor body 120 and the third conveyor body 130 and the risk of spontaneous combustion.

[0045] It should be noted that the detector here can be installed in the detection pipeline with a negative pressure fan, with the detection pipeline facing the predetermined position at the top of the second conveyor body 120 and the third conveyor body 130. In the process of not affecting the normal transportation of ore, the gas at the top of the ore is continuously sucked under negative pressure, and the concentration of the gas sucked under negative pressure is detected by the detection instrument.

[0046] When the first detector detects that the sulfur dioxide concentration exceeds the second set threshold, and the second detector also detects that the sulfur dioxide concentration exceeds the second set threshold, it indicates that the sulfur-containing ore on the surface of conveyor body 2 120 and conveyor body 3 130 is about to spontaneously combust. At this time, both conveyor body 3 130 and conveyor body 2 120 are controlled to convey clockwise. The sulfur-containing ore on the surface of conveyor body 3 130 is directly placed into the surface of conveyor body 2 120. The sulfur-containing ore on the surface of conveyor body 2 120 is placed into the protective chamber 200 through the telescopic interception component 400. At this time, the sulfur-containing ore on the surface of conveyor body 2 120 and conveyor body 3 130 that is about to spontaneously combust is placed into the protective chamber 200 at the maximum rate for isolation.

[0047] When the first detector detects that the sulfur dioxide concentration exceeds the second set threshold and the second detector detects that the sulfur dioxide concentration is below the second set threshold, it indicates that the sulfur-containing ore on the surface of the second conveyor body 120 is about to spontaneously combust, while the sulfur-containing ore on the surface of the third conveyor body 130 is still in a normal state. The second and third conveyor bodies 120 and 130 are controlled to rotate clockwise, with the conveying speed of the second conveyor body 120 being greater than that of the third conveyor body 130. The sulfur-containing ore on the surface of the second conveyor body 120 is then fed into the protective chamber 200 via the telescopic interception component 400. Simultaneously, because the conveying speed of the second conveyor body 120 is greater than that of the third conveyor body 130, the normal sulfur-containing ore on the surface of the third conveyor body 130 is fed onto the surface of the second conveyor body 120 more slowly. A buffer zone exists between the normal sulfur-containing ore and the sulfur-containing ore about to spontaneously combust, preventing excessive rotation of the second conveyor body 120 and thus avoiding the loss of normal sulfur-containing ore.

[0048] Similarly, the conveyor body 130 can be briefly stopped before resuming conveying. At this time, there is a gap between the normal sulfur-containing ore and the sulfur-containing ore that is about to spontaneously combust on the upper surface of the conveyor body 120, which can effectively distinguish sulfur-containing ore in different states and avoid the waste of normal sulfur-containing ore.

[0049] When the first detector detects a sulfur dioxide concentration below the second set threshold and the second detector detects a sulfur dioxide concentration above the second set threshold, it indicates that the sulfur-containing ore on the surface of conveyor body three 130 is about to spontaneously combust, while the sulfur-containing ore on the surface of conveyor body two 120 is in a normal state. First, control conveyor body three 130 to pause conveying and increase the conveying speed of conveyor body two 120 to its maximum. After the sulfur-containing ore on the surface of conveyor body two 120 has been conveyed, transfer the sulfur-containing ore from the surface of conveyor body two 120 to the surface of conveyor body one 110 to begin subsequent conveying. Then, control conveyor body three 130 to rotate clockwise at its maximum speed. The conveyor body 2 (120) rotates at a high speed, controlling it to rotate counterclockwise at its maximum speed. The sulfur-containing ore on the surface of the conveyor body 3 (130) passes over the left side of the conveyor body 2 (120) and is directly placed into the protective chamber 200. At this time, the sulfur-containing ore on the surface of the conveyor body 3 (130) that is about to spontaneously combust falls onto the surface of the conveyor body 2 (120) and moves a short distance counterclockwise before being placed into the protective chamber 200. This prevents the sulfur-containing ore from continuing to move a long distance along the surface of the conveyor body 2 (120), avoids the sulfur-containing ore that is about to spontaneously combust continuing to dry, avoids the generation of excessive sulfur dioxide, and minimizes the risk of spontaneous combustion.

[0050] Specifically, the protective chamber 200 includes a chamber body 210. A hopper 230 is located inside the upper part of the chamber body 210. A sealing component 220 is installed at the bottom of the hopper 230. During the feeding process, sulfur-containing ore passes through the sealing component 220 and enters the bottom of the chamber body 210. After the sulfur-containing ore is fed, the sealing component 220 is controlled to move upwards and fit against the bottom of the hopper 230 to achieve relative closure. Through this structural design, the sulfur-containing ore passes through the sealing component 220 along the hopper 230 and enters the chamber body 210 at the bottom of the sealing component 220, achieving centralized isolation. The chamber body 210 is filled with protective gases such as nitrogen to isolate and protect the sulfur-containing ore. Simultaneously, after the sulfur-containing ore is fed, the sealing component 220 seals the bottom of the hopper 230, reducing excessive sulfur dioxide overflow and decreasing the rate at which protective gas is filled into the chamber body 210, thus reducing processing requirements and resource consumption.

[0051] Specifically, the sealing component 220 includes a sealing positioning plate 211 fixedly connected to the bottom of the hopper 230. A sealing drive shaft 222 is rotatably connected to the inner wall of the sealing positioning plate 211. A sealing main plate 223 is fixed to the side wall of the sealing drive shaft 222. A discharge port 231 is opened at the bottom of the hopper 230. The size of the sealing main plate 223 is larger than that of the discharge port 231. During the process of ore passing through, the sealing main plate 223 is controlled to be in an inclined state, with a gap between it and the discharge port 231 to ensure the normal passage of ore. After the sulfur-containing ore is fed in, the sealing main plate 223 is controlled to deflect upward to a horizontal state, thereby sealing the bottom of the discharge port 231.

[0052] A torque elastic component can be provided between the enclosed mainboard 223 and the enclosed drive shaft 222 to buffer the sulfur-containing ore during the feeding process and prevent the sulfur-containing ore from directly impacting the enclosed drive shaft 222.

[0053] A jet opening is provided on the side wall of the enclosed main board 223. The jet opening is U-shaped and located on three consecutive side walls of the enclosed main board 223. During the process of adding sulfur-containing ore, the jet opening continuously sprays protective gas outward to mix with the sulfur-containing ore, filling the sulfur-containing ore in a protective atmosphere to prevent the sulfur-containing ore from spontaneously combusting.

[0054] An air duct 225 communicating with the jet opening is provided on the outside of the closed positioning plate 211. A rotary valve 224 is connected in series in the air duct 225 between the air duct 225 and the closed positioning plate 211. The rotary valve 224 is connected to the closed drive shaft 222.

[0055] The rotary valve 224 mentioned above can be an existing rotary valve. When the closed drive shaft 222 drives the closed main plate 223 to rotate to a horizontal state, the rotary valve 224 rotates synchronously and is in a closed state to avoid wasting protective gas. When the closed drive shaft 222 drives the closed main plate 223 to rotate to an inclined open state, the vent pipe 225 rotates synchronously and is in an open state. The protective gas in the vent pipe 225 passes through the closed assembly 220 and is finally ejected from the jet opening to mix with the sulfur-containing ore, thus preventing the sulfur-containing ore from further oxidizing and spontaneously combusting to produce excessive sulfur dioxide and heat.

[0056] Through the above structural design, the pumping of protective gas at the jet opening can be automatically adjusted and controlled according to the addition of sulfur-containing ore, without the need to install extra electronic detection components. It is simple, efficient, has high processing efficiency, and good protection effect.

[0057] An upper sealing plate 240 is slidably connected to the upper end of the hopper body 210. A linkage component 700 is provided between the upper sealing plate 240 and the conveying body 210. The linkage component 700 controls the upper sealing plate 240 to slide to different positions. Through the above structural design, the linkage component 700 can control the upper sealing plate 240 to be in different positions. The length of the upper sealing plate 240 is smaller than the opening size at the upper end of the hopper body 210, so as to accommodate... Figure 4For example, when the upper sealing plate 240 slides to the left position, the upper right side of the hopper 210 is open, allowing the sulfur-containing ore at the telescopic interception component 400 to be placed into the protective hopper 200; when the upper sealing plate 240 slides to the right position, the upper left side of the hopper 210 is open, allowing the sulfur-containing ore on the surface of the conveying body 2 120 to be directly placed into the protective hopper 200; through the above structural design, a gas isolation area can be further formed at the upper end of the hopper 230 to prevent the protective gas from spreading outwards, and the sulfur-containing ore can be initially isolated and protected by gas in the hopper 230, further preventing the sulfur-containing ore from spontaneously combusting and generating excessive sulfur dioxide and heat.

[0058] The aforementioned linkage component 700 can be selected as an electrically controlled telescopic rod for adjusting the horizontal position of the upper sealing plate 240, requiring the use of sensors for detection and control; the linkage component 700 can also be selected in the following manner: the linkage component 700 includes a linkage positioning frame 710 located on the outer side, a positioning frame rotatably connected to the inner wall of the linkage positioning frame 710, and a first linkage wheel 720 and a second linkage wheel 730 mutually abutting each other rotatably connected to the inner wall of the positioning frame, and a drive motor for driving the positioning frame to deflect is provided on the outer side of the linkage positioning frame 710. During the clockwise or counterclockwise reversal rotation of the conveying body 220, the positioning frame is controlled to drive the first linkage wheel 720 and the second linkage wheel 730 to deflect as a whole, controlling the first linkage wheel 720 and the second linkage wheel 730 to deflect as a whole. The first linkage wheel 720 is pressed against the belt at the bottom of the second conveyor body 120, and the second linkage wheel 730 is pressed against the upper surface of the lower upper sealing plate 240. The power of the belt of the second conveyor body 120 is transmitted to the upper end of the upper sealing plate 240 through the first linkage wheel 720 and the second linkage wheel 730 to control the upper sealing plate 240 to slide. After the upper sealing plate 240 slides to the limit position, it is limited. The second linkage wheel 730 cannot control the upper sealing plate 240 to continue sliding if it continues to rotate. After the second linkage wheel 730 continues to rotate for a predetermined time, the positioning frame is controlled to deflect in the opposite direction, and the first linkage wheel 720 and the second linkage wheel 730 are respectively offset from the belt and the upper sealing plate 240 to avoid continuous transmission of power.

[0059] The drive motor and the second conveyor body 120 are electrically connected. When the second conveyor body 120 rotates clockwise, it can transport sulfur-containing ore normally. At this time, the upper sealing plate 240 is in the left position, and an opening is formed on the right side for the sulfur-containing ore on one side of the telescopic interception component 400 to be put into the protective chamber 200. When the conveying direction of the second conveyor body 120 changes, the drive motor is controlled to rotate, and the first linkage wheel 720 and the second linkage wheel 730 are controlled to press against the outside to realize the transmission of power and realize the drive control of the upper sealing plate 240.

[0060] The working principle of the invention is further explained below with reference to each individual system.

[0061] The drying and protection system includes: a sulfur dioxide infrared detector, a drying chamber, a variable frequency fan, and an air heater.

[0062] Working principle: The blower is turned on, and the heater temperature is set simultaneously. Once the temperature inside the drying chamber reaches the specified level, the conveyor system is activated. Wet pyrite is transported by conveyor belt to the drying chamber inlet, leveled by the inlet scraper, and then enters the drying chamber. Hot air is used to heat the ore and remove excess moisture. Simultaneously, a sulfur dioxide concentration detector is installed at the drying chamber outlet. Based on the relationship between sulfur dioxide concentration, drying effect, and spontaneous combustion (when drying is insufficient, unreacted sulfides in the material easily decompose to produce sulfur dioxide, leading to an increase in the concentration in the tail gas (0.3~0.5%); localized overheating and spontaneous combustion of the material, with sulfur dioxide concentration > 0.5%), the following anti-spontaneous combustion system is set up. Sensors detect the sulfur dioxide concentration in real time. The data is processed by the acquisition module and transmitted to the central control system. The system compares the measured value with the safety threshold (0.3%). When the sulfur dioxide concentration is ≤0.3%, the drying parameters match the feeding conditions, resulting in good drying effect. Maintain the current drying parameters. When the sulfur dioxide concentration is ≤0.5% (0.3% < ≤ 0.3%), for every 0.05% increase in sulfur dioxide concentration, reduce the conveyor belt speed by 5% and increase the heating temperature by 4℃. This increases the residence time of the pyrite in the tunnel and the drying temperature difference, ensuring the drying parameters match the feeding and improving the drying effect (it should be noted that this assumes the sulfur dioxide concentration at all locations within the drying chamber is between 0.3% and 0.5%). When the sulfur dioxide concentration is >0.5%, the ore is about to spontaneously combust. Immediately stop feeding, increase the conveyor belt speed to maximum, and simultaneously open the baffle above the nitrogen protection chamber to quickly transfer the hazardous spontaneously combustible material into the nitrogen protection chamber to prevent further spontaneous combustion of the ore. Also, activate the audible and visual alarm to notify on-site personnel.

[0063] The raw material preheating system includes: a hopper-shaped feeding silo, a variable frequency fan, and a high-temperature gas duct.

[0064] Working Principle: The ore enters the feeding hopper, where an external fan draws high-temperature gas from the drying chamber to preheat the material. The high-temperature, humid gas then enters the coils within the feeding hopper via the fan, indirectly contacting and preheating the material. The power of the two fans in this location, along with those in the drying chamber, is adjusted as follows: The drying and sulfur dioxide monitoring system indicates three operating conditions within the drying chamber. When the sulfur dioxide concentration is ≤0.3%, the drying effect is good, and the fan power does not need adjustment. When the sulfur dioxide concentration is ≤0.5% (0.3% < 0.3%), the drying effect is poor, and the power of all three fans can be increased accordingly to increase the air velocity and reduce air humidity, thereby improving the mass transfer driving force of the drying process. In the event of spontaneous combustion, all fans are quickly shut down to prevent air from entering and promoting spontaneous combustion of the minerals. After heat exchange in the coils, the high-temperature, humid air is absorbed by the alkaline solution, preventing sulfur dioxide emissions into the atmosphere. The material falls from the feeding hopper onto the conveyor belt, and after on-site rectification, re-enters the tunnel for drying.

[0065] The gas purification system includes: an electrostatic precipitator, a dryer, and a variable frequency fan.

[0066] Working principle: High-temperature, humid gas drawn from the drying chamber by a fan enters the electrostatic precipitator. Under the action of direct current, the gas ionizes, generating a large number of electrons and ions. Dust particles combine with negative ions and become negatively charged. Under the influence of the electric field, the charged dust particles move towards the positive electrode (anode) and deposit. The gas after dust removal is used to heat the raw ore, and then enters the dryer to contact silica gel to remove moisture. The silica gel can be reused multiple times by heating to remove moisture. Finally, the gas is blown into the dryer by the fan to form a complete closed-loop cycle.

[0067] Key points of the invention

[0068] 1. Real-time monitoring and protection of sulfur dioxide: Sulfur dioxide monitoring is installed at the tail end of the tunnel. Once the concentration exceeds the upper limit of spontaneous combustion concentration, the spontaneously combusting ore is immediately introduced into the nitrogen protection chamber to prevent the ore from spontaneously combusting further.

[0069] 2. Closed-loop circulation drying system: The high-temperature and humid gas exiting the drying chamber is purified and dust is removed to ensure that the gas does not block the pipeline. At the same time, the gas temperature is dehumidified without lowering the gas temperature, which reduces the heating of the gas re-entering the drying chamber and lowers the energy consumption of the heater.

[0070] 3. Countercurrent heat exchange and preheating: The air and materials in the drying chamber come into contact in opposite directions, which increases the average heat exchange temperature difference. The lower-temperature hot air at the end is then used to preheat the raw ore, which reduces the use of high-temperature heat and realizes the cascade utilization of energy, significantly reducing the power consumption of the entire drying process.

[0071] Effects of the present invention

[0072] 1. Real-time early warning and proactive prevention: Through real-time detection of sulfur dioxide (response time < 5 seconds) and linkage control, intervention can be initiated before spontaneous combustion occurs (when the sulfur dioxide concentration is close to 0.5%), fundamentally preventing spontaneous combustion accidents.

[0073] 2. Improve operational safety: In the event of spontaneous combustion, the burning ore can be quickly transferred to a nitrogen protection chamber to inhibit oxidation, prevent large-scale leakage of sulfur dioxide, and eliminate personnel poisoning accidents.

[0074] 3. Adaptable to raw material fluctuations: Even if the sulfur content and moisture content of the raw materials fluctuate, the drying parameters can be matched accordingly, achieving both thorough drying and low energy consumption.

[0075] 4. Optimized drying efficiency: Hot air comes into countercurrent contact with the ore, which enhances the mass and heat transfer rate between the gas and solid phases. The lower-grade hot air at the outlet exchanges heat with the raw material, which greatly improves the utilization rate of waste heat. Compared with traditional tunnel dryers, energy consumption is reduced by 12% and the throughput is increased by 8%.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tunnel drying process for sulfur-containing ores with anti-self-ignition function, using tunnel drying equipment with anti-self-ignition function, the tunnel drying equipment including a drying chamber (300) and a conveyor belt (100) passing through the bottom of the drying chamber (300), characterized in that: It also includes a protective chamber (200), which is located below the end of the conveyor belt (100). The protective chamber (200) includes a retractable telescopic interception component (400). The drying chamber (300) is also equipped with a detector for detecting sulfur dioxide concentration. Run it as follows: First, sulfur-containing ore is placed on the upper surface of the conveyor belt (100). The conveyor belt (100) directionally transports the sulfur-containing ore from the inlet end of the drying chamber (300) to the outlet end, achieving continuous drying of the sulfur-containing ore during the transport process. The detector continuously monitors the concentration of sulfur dioxide in the drying chamber (300); the detector is electrically connected to the conveyor belt (100); The detector has a first set threshold and a second set threshold. When the sulfur dioxide concentration in the drying chamber (300) is lower than the first set threshold, the conveyor belt (100) is controlled to transport the sulfur-containing ore at a normal speed. When the sulfur dioxide concentration in the drying chamber (300) is greater than the first set threshold and less than the second set threshold, the conveying speed of the conveyor belt (100) is increased. When the sulfur dioxide concentration in the drying chamber (300) is greater than the second set threshold, the telescopic interception component (400) is controlled to extend outward. After the telescopic interception component (400) extends outward, the speed of the conveyor belt (100) is increased to the maximum. The sulfur-containing ore slides down through the telescopic interception component (400) into the protective chamber (200) for centralized storage. Protective gas is pumped into the protective chamber (200) to encapsulate the sulfur-containing ore.

2. The tunnel drying process for sulfur-containing ores with anti-self-ignition function according to claim 1, characterized in that, The conveyor belt (100) is stepped with multiple components, including a third conveyor body (130) and a second conveyor body (120) located inside the drying chamber (300), and a first conveyor body (110) located outside the drying chamber (300). The second conveyor body (120) is located between the third conveyor body (130) and the first conveyor body (110). The protective chamber (200) is located at a predetermined position at the lower end of the second conveyor body (120). The telescopic interception component (400) is arranged at an angle near the first conveyor body (110). When the sulfur dioxide concentration in the drying chamber (300) is greater than the second set threshold, the telescopic interception component (400) is controlled to extend outward. After extending, the telescopic interception component (400) is located between the first conveyor body (110) and the second conveyor body (120) to intercept the sulfur-containing ore.

3. The tunnel drying process for sulfur-containing ores with anti-self-ignition function according to claim 2, characterized in that, The horizontal projection of the second conveying body (120) away from the telescopic interception component (400) is located within the horizontal projection of the protective chamber (200). At least two detectors are provided. The first detector is opposite to the second conveying body (120). Based on the different concentrations of sulfur dioxide detected by the two detectors, the second conveying body (120) and the third conveying body (130) are controlled to transport the sulfur-containing ore clockwise or counterclockwise or paused and then clockwise.

4. The tunnel drying process for sulfur-containing ores with anti-self-ignition function according to claim 1, characterized in that, The protective bin (200) includes a bin body (210), and a hopper (230) is located inside the upper end of the bin body (210). A sealing component (220) is provided at the bottom of the hopper (230). During the feeding process of sulfur-containing ore, it passes through the sealing component (220) and enters the bottom position of the bin body (210). After the sulfur-containing ore is fed, the sealing component (220) is controlled to move upward and fit against the bottom of the hopper (230) to achieve relative closure.

5. The tunnel drying process for sulfur-containing ores with anti-self-ignition function according to claim 4, characterized in that, The enclosed assembly (220) includes an enclosed positioning plate (211) fixedly connected to the bottom of the hopper (230). The inner wall of the enclosed positioning plate (211) is rotatably connected to an enclosed drive shaft (222). The side wall of the enclosed drive shaft (222) is fixed with an enclosed main plate (223). The bottom of the hopper (230) has a discharge port (231). The size of the enclosed main plate (223) is larger than the size of the discharge port (231).

6. The tunnel drying process for sulfur-containing ores with anti-self-ignition function according to claim 5, characterized in that, The side wall of the closed main board (223) is provided with a jet opening, and the outer side of the closed positioning plate (211) is provided with a ventilation pipe (225) communicating with the jet opening. A rotary valve (224) is provided between the ventilation pipe (225) and the closed positioning plate (211) and is connected in series in the ventilation pipe (225). The rotary valve (224) is connected to the closed drive shaft (222).

7. The tunnel drying process for sulfur-containing ores with anti-self-ignition function according to claim 4, characterized in that, The upper end of the hopper (210) is slidably connected to an upper sealing plate (240). A linkage component (700) is provided between the upper sealing plate (240) and the second conveying body (120). The upper sealing plate (240) is controlled to slide to different positions by the linkage component (700).

8. The tunnel drying process for sulfur-containing ores with anti-self-ignition function according to claim 7, characterized in that, The linkage assembly (700) includes a linkage positioning frame (710) located on the outer side. A positioning frame is rotatably connected to the inner wall of the linkage positioning frame (710). A first linkage wheel (720) and a second linkage wheel (730) that abut against each other are rotatably connected to the inner wall of the positioning frame. A drive motor for driving the positioning frame to deflect is provided on the outer side of the linkage positioning frame (710).

9. The tunnel drying process for sulfur-containing ores with anti-self-ignition function according to claim 1, characterized in that, The first set threshold is 0.3%, and the second set threshold is 0.5%.

10. The tunnel drying process for sulfur-containing ores with anti-self-ignition function according to claim 1, characterized in that, The inlet end of the drying chamber (300) is provided with a feeding hopper (500), and a serpentine heat exchange coil is provided on the outside of the feeding hopper (500). The coil and the drying chamber (300) are connected by a flow guide heat exchange component (600) to form an airflow circulation.

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