Sintering method

Abstract

The invention relates to a sintering method which comprises the following steps: S1, heating and ventilating: heating a sintering furnace and introducing gas into the sintering furnace to enable the temperature in the sintering furnace to reach a preset temperature and form rising airflow; s2, sintering is conducted, specifically, materials needing to be sintered are added into a sintering furnace, the materials pass through the sintering furnace by means of the self weight and are kept in a dispersed state and a slow descending state under the blowing action of airflow, and the materials are sintered when passing through the sintering furnace; and S3, cooling is conducted, specifically, the sintered materials leave the sintering furnace by means of the self weight and then enter a discharging pipeline, the materials pass through the discharging pipeline by means of the self weight, and the materials are cooled when passing through the discharging pipeline. By means of the sintering method, the sintering quality and the sintering efficiency can be improved, and the height of the sintering furnace can be relatively low.

Description

Technical Field

[0001] This invention relates to the field of sintering technology, and in particular to a sintering method. Background Technology

[0002] In my country's electronics, electrical engineering, solar energy, powder metallurgy, display, and water filtration industries, powdered non-metallic materials or rare metal powders are widely used. These powders need to be sintered in a high-temperature furnace before being put into use. Chinese invention patent CN115127338B discloses a sintering production line, including: a kiln, a kiln car conveyor line, a receiving device, a feeding conveyor line, and a loading / unloading device. The kiln car conveyor line includes multiple kiln cars carrying kilns that circulate along a closed-loop conveying route. The conveying route includes a sintering section and a loading / unloading section. The kiln is located in the sintering section for heating and sintering the kilns. The receiving device is located upstream of the loading / unloading section for collecting sintered materials. The feeding conveyor line is located downstream of the loading / unloading section for loading empty kilns with the powder to be sintered. The loading / unloading device is used to move the kilns between the kiln cars carrying kilns, the receiving device, and the feeding conveyor line. In the aforementioned sintering production line, the material to be sintered is placed in a sagger. On the one hand, the material tends to stick to the sagger during the sintering process, resulting in incomplete reaction, a high impurity content in the final product, and affecting the sintering quality. On the other hand, the material piles up in the sagger, leading to a longer sintering time and reduced sintering efficiency. How to improve both sintering quality and efficiency is a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0003] Therefore, the present invention provides a sintering method that can improve sintering quality and sintering efficiency, and the height of the sintering furnace can be relatively low.

[0004] To solve the above-mentioned technical problems, the present invention provides a sintering method, comprising the following steps: S1. Heating and gas supply: Heating the sintering furnace and introducing gas into it to bring the furnace to a preset temperature and create an upward airflow. S2, Sintering: The material to be sintered is added to the sintering furnace. The material passes through the sintering furnace by its own weight and is kept in a dispersed state and a slow downward state under the blowing action of the airflow. The material is sintered when it passes through the sintering furnace. S3. Cooling: After sintering, the material leaves the sintering furnace by its own weight and enters the discharge pipe. The material is cooled as it passes through the discharge pipe.

[0005] Furthermore, the preset temperature is 300℃-1300℃.

[0006] Furthermore, gas enters the sintering furnace horizontally from different positions in the circumferential and vertical directions, and the gas flow passes through the sintering furnace in a spiral upward direction.

[0007] Furthermore, the material to be sintered enters the sintering furnace from different positions around the circumference of the furnace in an inclined downward direction, and the material passes through the sintering furnace in a spiral downward direction.

[0008] Furthermore, the air flow rate when introducing gas into the sintering furnace is a, the mass flow rate when adding the material to be sintered into the sintering furnace is b, and the percentage of metallic manganese in the material to be sintered is x%, where a≥1.3bx%, and x% is 45%-90%.

[0009] Furthermore, the velocity of the rising airflow is 1 m / s to 2 m / s.

[0010] Furthermore, the material passes through the discharge pipe in a downward inclined direction.

[0011] Furthermore, when the material passes through the discharge pipe, it is first cooled by direct air blowing, and then cooled by heat exchange through a cooling medium.

[0012] Furthermore, it also includes the following steps: S4. Cooling and dust removal: The dust-laden gas discharged from the sintering furnace and / or discharge pipe is cooled and dust removed to obtain clean gas. The clean gas is sent into the sintering furnace to blow the sintered material and / or the clean gas is sent into the discharge pipe to cool the sintered material.

[0013] Furthermore, the material to be sintered is manganese, and the gas is air.

[0014] Compared with the prior art, the above-mentioned technical solution of the present invention has the following advantages: The sintering method of the present invention forms an upward airflow in the sintering furnace. On the one hand, the upward airflow keeps the material in the sintering furnace in a moving and dispersed state, reducing the problem of material agglomeration during the sintering process, and thus making it less likely to stick to the inner wall of the sintering furnace, so that the material is completely sintered and the sintering quality is guaranteed. Moreover, the material is heated evenly in a dispersed state, with a large heating area, which improves the sintering efficiency. On the other hand, the upward airflow increases the resistance of the material to the downward movement, prolongs the time the material stays in the sintering furnace, and allows the height of the sintering furnace to be relatively low. Attached Figure Description

[0015] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0016] Figure 1 This is a flowchart of the sintering method in this invention; Figure 2 This is a schematic diagram of the sintering system in this invention; Figure 3 This is a schematic diagram showing the connection between the sintering furnace and the discharge pipe in this invention; Figure 4 The XRD pattern is shown in Example 1. Figure 5 This is the XRD pattern for Comparative Example 1.

[0017] Explanation of reference numerals in the instruction manual: 11. Sintering furnace; 111. First air inlet; 112. Feeding port; 113. First exhaust port; 114. Discharge port; 115. Venting port; 116. Explosion-proof port; 12. Burner; 13. Discharge guide plate; 2. Air supply device; 3. Feeding device; 4. Discharge cooling device; 41. Discharge pipe; 411. Second air inlet; 412. Second exhaust port; 42. Water cooling equipment; 5. Material receiving device; 6. Dust removal device; 7. Exhaust cooling device. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0019] See Figures 1 to 3 This invention discloses an embodiment of the sintering method.

[0020] The sintering method includes the following steps: S1. Heating and gas supply: Heating the sintering furnace 11 and introducing gas into the sintering furnace 11 to achieve the preset temperature and form an upward airflow. S2, Sintering: The material to be sintered is added to the sintering furnace 11. The material passes through the sintering furnace 11 by its own weight and is kept in a dispersed state and a slow downward state under the blowing action of the airflow. The material is sintered when it passes through the sintering furnace 11. S3. Cooling: After sintering, the material continues to leave the sintering furnace 11 by its own weight and enters the discharge pipe 41. The material is cooled as it passes through the discharge pipe 41 by its own weight.

[0021] In the above description, the sintering furnace 11 is preheated to the temperature range required for the reaction of the material to be sintered. Before the material is added to the sintering furnace 11, an upward airflow is formed within the furnace, creating a uniform hydrodynamic environment. After the material is added to the furnace, it begins to fall under gravity. The upward airflow exerts a counterforce on the material particles, causing the particle group to disperse and slowly pass through the high-temperature zone. During this process, sufficient spacing is maintained between the particles, and their surfaces are fully exposed to the hot airflow, achieving non-contact, uniform sintering. Once the sintered material leaves the furnace 11, it immediately enters the discharge pipe 41, which has a temperature control function. The material continues to move in a loose state under gravity, maintaining the continuity of the sintering production line and avoiding phase change reactions caused by the accumulation of high-temperature material.

[0022] Specifically, the above sintering method is implemented using the following sintering system. The sintering system includes: The sintering apparatus includes a sintering furnace 11 and a burner 12 for creating a high-temperature environment inside the sintering furnace 11. The sintering furnace 11 is provided with a first air inlet 111 for receiving gas, a feeding port 112 for receiving materials to be sintered, a first exhaust port 113 for discharging gas, and an outlet 114 for discharging sintered materials. The first air inlet 111 and the outlet are located near the bottom of the sintering furnace 11, and the feeding port 112 and the first exhaust port 113 are located near the top of the sintering furnace 11. The air supply device 2 is connected to the first air inlet 111 of the sintering furnace 11 and is used to supply gas into the sintering furnace 11. The feeding device 3 is connected to the feeding port 112 of the sintering furnace 11 and is used to feed the material to be sintered into the sintering furnace 11. The discharge cooling device 4 includes a discharge pipe 41 connected to the discharge port 114 of the sintering furnace 11, which is used to cool and discharge the sintered material. The material receiving device 5 is connected to the material output end of the above-mentioned discharge cooling device 4 and is used to collect the cooled material.

[0023] The interior of the sintering furnace 11 is used for the sintering reaction. The first air inlet 111 is the channel for gas to enter the sintering furnace 11, the feeding port 112 is the channel for the material to be sintered to enter the sintering furnace 11, and the first exhaust port 113 is the channel for gas to exit the sintering furnace 11. The first air inlet 111 and the first exhaust port 113 are located near the bottom and top of the sintering furnace 11, respectively, to facilitate the formation of an upward airflow. The feeding port 112 and the discharge port 114 are located near the top and bottom of the sintering furnace 11, respectively, to facilitate the passage of the material to be sintered through the sintering furnace 11 by its own weight. The burner 12 is a gas device capable of generating a directional high-temperature flame, providing a high-temperature environment for the sintering furnace 11. The air supply device 2 is connected to the first air inlet 111 at the bottom of the sintering furnace 11, supplying gas into the sintering furnace 11; this can be achieved using a high-pressure blower or a forced draft fan. The feeding device 3 feeds material into the feeding port 112 at the top of the sintering furnace 11. The discharge cooling device 4 is used to receive the material output from the sintering furnace 11 and to convey and cool the material. The receiving device 5 is located at the material output end of the discharge cooling device 4 and collects the material. Specifically, it can be implemented using a receiving bucket. When material needs to be discharged, the material output end of the discharge cooling device 4 is opened to collect the material after sintering and cooling.

[0024] Through the above technical solution, by forming an upward airflow in the sintering furnace 11, on the one hand, the upward airflow keeps the material in the sintering furnace 11 in a moving and dispersed state, reducing the problem of material agglomeration during the sintering process, and thus making it less likely to stick to the inner wall of the sintering furnace 11, so that the material is sintered completely and the sintering quality is guaranteed. Moreover, the material is heated evenly in a dispersed state, with a large heating area, which improves the sintering efficiency. On the other hand, the upward airflow increases the resistance of the material to the downward movement, prolonging the time the material stays in the sintering furnace 11, so that the height of the sintering furnace 11 can be relatively low to achieve sufficient sintering.

[0025] In this embodiment, the preset temperature is 300℃-1300℃.

[0026] The core of sintering is achieving metallurgical bonding between particles (such as forming neck connections) through gas-solid phase oxidation reactions and atomic diffusion. At low temperatures, insufficient atomic kinetic energy and slow diffusion rates result in only weak local connections between particles, or even a loosely packed state. At high temperatures, the atomic diffusion rate accelerates significantly, and grains grow by engulfing smaller grains, forming coarse grains. This leads to "coarse-grained embrittlement," a significant decrease in toughness, and the potential appearance of an "orange peel" texture on the surface. Manganese powder burns at approximately 450°C in air and at 300°C in pure oxygen, and the heat released during combustion can provide energy for self-propagation. In actual sintering, the aforementioned preset temperatures are set according to the combustion requirements of different materials.

[0027] Specifically, the preset temperatures are 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, 1250℃, or 1300℃.

[0028] By setting the preset temperature within a suitable range through the above technical solution, the lower temperature limit ensures that the oxide reduction reaction proceeds fully during the sintering process of manganese materials, while the upper temperature limit prevents the metallic manganese particles from melting and agglomerating. This improves the sintering quality while maintaining the production efficiency of continuous material falling.

[0029] In this embodiment, gas enters the sintering furnace 11 from different positions in the circumferential and vertical directions, and the gas flow passes through the sintering furnace 11 in a spiral upward direction.

[0030] As described above, when the gas enters the sintering furnace 11, it forms a rotating upward flow field along the inner wall of the sintering furnace 11. After the material enters the sintering furnace 11, it is lifted by the spiral upward airflow, generating centrifugal force, which keeps the particles spaced apart.

[0031] Specifically, the sintering furnace 11 is provided with multiple first air inlets 111, which are evenly distributed on the side wall of the sintering furnace 11 along a spiral direction centered on the vertical axis (central axis) of the sintering furnace 11. This can be understood as the first air inlets 111 being arranged in a spiral trajectory in the circumferential direction, for example, in a clockwise or counterclockwise direction, staggered at certain angles at different height levels. The first air inlets are equally spaced angularly in the circumferential direction and distributed at certain intervals (such as equidistant or gradually varying intervals) in the height direction.

[0032] Through the above technical solution, the gas enters from the first air inlet at different heights and angles, forming a spiral upward airflow in the sintering furnace 11. This causes the gas to form a swirling flow when it enters the furnace, improving the uniformity of gas distribution, increasing the contact time and mixing uniformity between the gas and the material, and avoiding local dead zones in the airflow.

[0033] In this embodiment, the material to be sintered enters the sintering furnace 11 from different circumferential positions along an inclined downward direction, and the material passes through the sintering furnace 11 in a spiral downward direction.

[0034] In the above text, the downward tilt refers to the trajectory of the material during the feeding process, which forms an angle with the horizontal plane under the action of gravity. The tilted feeding angle, combined with the spiral airflow trajectory, effectively eliminates the local accumulation phenomenon caused by vertical feeding and achieves complete reaction by extending the residence time of the material in the high-temperature zone.

[0035] Specifically, the sintering furnace 11 is provided with a plurality of feeding ports 112, which are evenly distributed on the side wall of the sintering furnace 11 along a circumferential direction with the vertical axis of the sintering furnace 11 as the central axis. This can be understood as all feeding ports 112 being located on the same horizontal circumference, and the angular intervals between adjacent feeding ports 112 being equal. The centerline of all feeding ports 112 is equidistant from the central axis of the sintering furnace 11, ensuring that the material enters the sintering furnace 11 uniformly.

[0036] Through the above technical solution, multiple feeding ports 112 feed simultaneously, allowing the material to be evenly distributed circumferentially within the sintering furnace 11. This avoids localized accumulation or gaps in the material, improves feeding uniformity, ensures even material distribution, prevents material concentration on one side, and ensures a more stable sintering process. The downward-sloping feeding direction extends the residence time of the material within the sintering furnace 11, ensuring that the material is fully sintered.

[0037] In this embodiment, the air flow rate when gas is introduced into the sintering furnace 11 is a, the mass flow rate when the material to be sintered is added to the sintering furnace 11 is b, and the percentage of metallic manganese in the material to be sintered is x%, a≥1.3bx%, where x% is 45%-90%.

[0038] In the above text, airflow rate refers to the volume of gas passing through the sintering furnace per unit time, measured in cubic meters per hour, while mass flow rate refers to the mass of material fed into the sintering furnace per unit time, measured in kilograms per hour. By controlling the ratio of these two parameters, the airflow is given the necessary power to carry the material. In this embodiment, the airflow rate is set using the aforementioned air supply device 2.

[0039] Wherein, the mass fraction of metallic manganese = x% (45% ≤ x ≤ 90%) The mass fraction of manganese tetroxide is y% (10% ≤ y ≤ 45%), and x + y = 100%. Composition of air: The volume fraction of oxygen in dry air is approximately 21%. The density of O2 is approximately 1429 g / m³ = 1.429 g / L. 3Mn + 2O2 → Mn3O4

[0040] The required mass of oxygen is 21.35g. Calculate: = (55 * 2 * 31.998) / (54.938 * 3) = 63.996x / 164.8; Oxygen volume = oxygen mass / oxygen density = 21.35 / 1429 = 0.01494 m3; Note: 1 m³ = 1000 L; Since oxygen makes up approximately 21% of the air (by volume), the required air volume is: Air volume = Oxygen volume / Oxygen volume fraction = 0.01494 / 0.21 = 0.0711 m3; Converted to hourly ventilation (a, m³ / h); Mixture feeding rate: For example, the initial mixture is fed at a rate of b kg / h per hour.

[0041] For every 100 grams of the mixture (55g of metallic manganese powder), 0.0711 m³ of air is required; a = b * 0.071 / 0.1 = 0.71b (m³ / h); The proportion of elemental manganese (x) is 45%-90%. a = b * air volume = b * (oxygen volume / oxygen volume fraction); =b*(63.996*x% / 164.8)*1000 / 1429 / 0.21=1.293*b*x%≈1.3bx%; When x = 45%: a = 0.582b; When x = 55%: a = 0.711b; When x = 90%, a = 1.164b.

[0042] Specifically, when the material enters the sintering furnace 11 at a mass flow rate b, the constraint condition of air flow rate a ≥ 1.3bx% ensures that the manganese powder is fully burned and sintered uniformly, thereby obtaining high-purity manganese tetroxide.

[0043] By setting the flow rates of the rising airflow and the falling material flow rates within a suitable range through the above technical solution, the material passes through the sintering furnace 11 at a better speed, ensuring sintering quality and sintering efficiency.

[0044] In this embodiment, the velocity of the rising airflow is 1m / s-2m / s.

[0045] In the above text, the vertical velocity of the rising airflow is controlled within the range of 1-2 m / s. This velocity range can provide dynamic support for the material, generating sufficient lifting force to maintain material dispersion while preventing excessive blowing that could cause the material to detach from the sintering path or be unable to descend.

[0046] Specifically, during the sintering process, when the airflow velocity reaches 1 m / s, the material particles are prevented from falling too quickly due to their own weight and accumulating. When the velocity does not exceed 2 m / s, the material can still maintain contact time with the high-temperature zone during its descent, ensuring thorough sintering. Within this velocity range, the material is constrained in a downward spiral trajectory, forming uniform gaps between particles, thereby improving heat transfer efficiency. Specifically, the upward airflow velocity is 1 m / s, 1.5 m / s, or 2 m / s.

[0047] By setting the velocity of the rising airflow within a suitable range through the above technical solution, the material is uniformly heated in a dispersed state, while ensuring the integrity of the sintering path, thereby improving sintering quality and efficiency.

[0048] In this embodiment, the material passes through the discharge pipe 41 in a downward inclined direction.

[0049] In the above text, the downward tilt direction refers to the trajectory of the material under the action of gravity, which forms an angle with the horizontal plane.

[0050] Specifically, the bottom of the sintering furnace 11 is provided with a discharge guide plate 13. Both the discharge guide plate 13 and the discharge pipe 41 are inclined. The discharge guide plate 13 guides the sintered material to slide into the discharge pipe 41 by its own weight. The discharge pipe 41 guides the material to pass through in a downward inclined direction by its own weight. The discharge guide plate 13 refers to the inclined flow guiding structure set at the bottom of the sintering furnace 11. This structure guides the material to slide in a specific direction, avoiding material accumulation in the discharge port area. The inclined arrangement of the discharge pipe 41 means that the entire channel is arranged in a downward inclined structure, and the inclination direction of the discharge pipe 41 forms a continuous path with the flow guiding direction of the discharge guide plate 13. This structure uses gravity to maintain the continuous flow of material and prevents local temperature unevenness caused by stagnation during the cooling process.

[0051] By setting the discharge direction to be inclined downward through the above technical solution, the material transmission path forms a continuous gravity-driven system, which eliminates power consumption and improves the overall operating efficiency of the sintering system.

[0052] In this embodiment, when the material passes through the discharge pipe 41, it is first cooled by direct air blowing, and then cooled by heat exchange through a cooling medium.

[0053] In the above text, direct airflow refers to a cooling method that uses forced convection to impact the surface of high-temperature materials with airflow. Cooling medium heat exchange refers to a cooling method that uses a low-temperature medium to absorb heat from materials through indirect contact.

[0054] Specifically, the aforementioned discharge cooling device 4 further includes an air-cooling device (not shown in the figure) and a water-cooling device 42 for creating a low-temperature environment within the discharge pipe 41. The discharge pipe 41 includes an air-cooling section and a water-cooling section connected vertically. The air-cooling section is provided with a second air inlet 411 for receiving gas and a second exhaust outlet 412 for discharging gas. The air-cooling device is connected to the second air inlet 411 and is used to blow cold air into the air-cooling section. The water-cooling device 42 is located outside the water-cooling section and is used for heat exchange with the water-cooling section. The air-cooling section refers to a channel for preliminary cooling of high-temperature materials through gas flow, and the air-cooling device is an air supply device. The second air inlet 411 is an interface for supplying gas to the air-cooling section and is used to apply a controllable airflow to the surface of the material. The water-cooled section refers to the channel through which materials are cooled in a secondary manner by a cooling medium. The water-cooled equipment 42 includes a water-cooled channel, which is a closed pipeline used to circulate the cooling medium. Specifically, it can be implemented by using a jacket or coil surrounding the side wall of the water-cooled section, and the heat is carried away by the circulating liquid medium.

[0055] By combining air cooling and water cooling modes, the above technical solution reduces thermal stress concentration through phased heat dissipation.

[0056] This embodiment also includes the following steps: S4. Cooling and dust removal: The dust-laden gas discharged from the sintering furnace 11 and / or the discharge pipe 41 is cooled and dust removed to obtain clean gas. The clean gas is sent into the sintering furnace 11 to blow the sintered material and / or the clean gas is sent into the discharge pipe 41 to cool the sintered material.

[0057] In the above text, cooling and dust removal refers to the cooling and filtration of high-temperature gas containing solid particles. This process avoids thermal damage to equipment caused by direct dust removal of high-temperature, dust-laden gas. Clean gas ensures that it will not cause secondary pollution to the sintering materials during recycling.

[0058] Specifically, the gas is cooled and dusted using a dust removal device 6 and an exhaust cooling device 7. The dust removal device 6 is connected to the first exhaust port 113 of the sintering furnace 11 via the exhaust cooling device 7, and is used to separate dust from the dust-laden gas discharged from the sintering furnace 11. The second exhaust port 412 of the air-cooled section is connected to the exhaust cooling device 7. The dust removal device 6 is a device that achieves gas-solid separation, trapping dust particles in the gas through filtration or centrifugation. The exhaust cooling device 7 is a device that cools the high-temperature dust-laden gas, reducing the gas temperature to a suitable range for dust removal and preventing damage to subsequent equipment due to high temperatures.

[0059] Through the above technical solution, the waste gas generated during the sintering and cooling processes can be cooled and dust removed, allowing the waste gas to be recycled and reused without polluting the environment.

[0060] In this embodiment, the material to be sintered is manganese, and the gas is air.

[0061] In the above text, manganese materials refer to powdered compounds or alloy materials with manganese as the main component. Air provides the necessary oxygen source for the oxidation reaction of manganese materials at high temperature, while maintaining the dispersion of materials through airflow.

[0062] Specifically, the manganese material is a mixture of elemental manganese and manganese tetroxide. The main purpose of the mixture is to prevent violent reactions inside the furnace, which could lead to severe deflagration and ultimately an explosion.

[0063] By applying the above sintering method to the sintering of manganese materials through the above technical solution, on the one hand, air provides downward resistance for manganese materials, and on the other hand, air provides a reaction atmosphere for manganese materials, achieving two goals at once.

[0064] In this embodiment, the sintering apparatus includes a plurality of burners 12, which are evenly distributed on the side wall of the sintering furnace 11 along a spiral direction centered on the vertical axis of the sintering furnace 11.

[0065] In the above description, multiple burners 12 are evenly distributed spirally along the side wall of the sintering furnace 11. The burners are arranged in a spiral pattern in the circumferential direction, with each burner staggered at a certain angle relative to the layer above, and distributed at fixed intervals in the height direction. The burners at the same height layer have equal angular intervals, forming a three-dimensional interlaced heating network.

[0066] Through the above technical solution, the spirally distributed burners 12 spray flames into the sintering furnace 11 from different heights and angles, forming a three-dimensional heating field, which can heat the materials more evenly.

[0067] In this embodiment, the sintering furnace 11 is further provided with a vent 115 for discharging gas and an explosion-proof port 116 for depressurization. The vent 115 and the explosion-proof port 116 are both provided on the side wall of the sintering furnace 11. A filter screen is connected to the vent 115 and an explosion-proof valve is connected to the explosion-proof port 116.

[0068] In the above text, the vent 115 is used to discharge the waste gas generated during the sintering process and maintain stable pressure inside the furnace. The vent 115 is located below the feeding port 112. The vent 115 is designed with a filter screen (with positive pressure inside the cavity) to prevent backflow of exhaust gas during feeding, which would cause material waste. An air blowing device can be added as needed to more evenly feed the material into the furnace. The explosion-proof port 116 refers to the pressure relief channel set on the side wall of the sintering furnace 11. When the pressure inside the sintering furnace 11 exceeds the preset value, the explosion-proof valve automatically opens.

[0069] Through the above technical solution, precise control of the gas emission flow and pressure dynamic balance in the sintering furnace 11 is achieved, avoiding pressure overload in the sintering furnace 11.

[0070] In this embodiment, the exhaust cooling device 7 is a jacketed air-cooled pipe.

[0071] In the above text, the jacketed air-cooled pipe absorbs the heat of the gas through the cooling air in the jacket, achieving non-contact cooling and avoiding gas contamination.

[0072] Specifically, the high-temperature dust-laden gas discharged from the sintering furnace 11 passes through the pipes in the inner shell of the jacketed air-cooling pipe. The cooling air circulates in the space between the outer and inner shells of the jacketed air-cooling pipe, expanding the heat exchange area and improving the heat transfer efficiency between the high-temperature gas and the cooling air. At the same time, the airtightness of the gas flow path is maintained to prevent dust leakage.

[0073] Through the above technical solution, the jacketed air-cooled pipe can reliably cool the discharged high-temperature gas, so that the temperature of the cooled gas meets the requirements of the dust removal device 6.

[0074] Example 1 Materials: 55% manganese powder + 45% manganese tetroxide, x% is 55%; Gas: Air (oxygen content 21%), airflow rate 8 m³ / h Sintering furnace temperature: 300℃ (initial) → After self-propagation, the temperature is controlled at 900℃±50℃ (manganese combustion exothermic heat + external heating). Airflow velocity: 1.5 m / s (updraft) Material flow rate (b): 10 kg / h; Airflow rate (a) and material flow rate (b): a≈1.45bx% (satisfying a≥1.3bx%) Experimental procedure: Air is introduced into the sintering furnace to form an upward airflow of 1.5 m / s, and the initial furnace temperature is 300℃.

[0075] Add manganese powder with a mass fraction of 55% + 45% manganese tetroxide at a flow rate of 10 kg / h, with an airflow rate of 8 m³ / h (a≈1.45bx%).

[0076] The material slowly descends under the action of airflow (the falling speed is reduced to 30% of free fall) and self-combusts in the furnace (releasing heat to 900℃±50℃).

[0077] The sintered product enters the discharge pipe, is first cooled to 200°C by blowing air, and then cooled to room temperature by water.

[0078] The obtained material is manganese tetroxide, with a tap density of 2.96 g / cm³, and the phase is 100% manganese tetroxide.

[0079] Comparative Example 1: Materials: 55% manganese powder + 45% manganese tetroxide, x% is 55%; Gas: Air (oxygen content 21%), airflow rate 6 m³ / h Sintering furnace temperature: 300℃ (initial) → After self-propagation, the temperature is controlled at 900℃±50℃ (manganese combustion exothermic heat + external heating). Airflow velocity: 1.5 m / s (updraft) Material flow rate (b): 10 kg / h Airflow (a) and material flow (b): a≈1.09bx% (a < 1.3bx%) Experimental procedure: Air is introduced into the sintering furnace to form an upward airflow of 1.5 m / s, and the initial furnace temperature is 300℃.

[0080] Add manganese powder with a mass fraction of 55% + 45% manganese tetroxide at a flow rate of 10 kg / h, with an airflow rate of 6 m³ / h (a≈1.09bx%).

[0081] The material slowly descends under the action of airflow (the falling speed is reduced to 30% of free fall) and self-combusts in the furnace (releasing heat to 900℃±50℃).

[0082] The sintered product enters the discharge pipe, is first cooled to 200°C by blowing air, and then cooled to room temperature by water.

[0083] The resulting material is a mixture of manganese tetroxide, metallic manganese, and manganese oxide. The metallic manganese was not completely burned, and both metallic manganese and manganese oxide were present in the phase.

[0084] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A sintering method, characterized in that, Includes the following steps: S1. Heating and gas supply: Heating the sintering furnace and introducing gas into it to bring the furnace to a preset temperature and create an upward airflow. S2, Sintering: The material to be sintered is added to the sintering furnace. The material passes through the sintering furnace by its own weight and is kept in a dispersed state and a slow downward state under the blowing action of the airflow. The material is sintered when it passes through the sintering furnace. S3. Cooling: After sintering, the material leaves the sintering furnace by its own weight and enters the discharge pipe. The material is cooled as it passes through the discharge pipe.

2. The sintering method according to claim 1, characterized in that, The preset temperature is 300℃-1300℃.

3. The sintering method according to claim 1, characterized in that, Gas enters the sintering furnace horizontally from different positions in the circumferential and vertical directions, and the gas flow passes through the sintering furnace in a spiral upward direction.

4. The sintering method according to claim 3, characterized in that, The material to be sintered enters the sintering furnace from different positions around the circumference of the furnace in an inclined downward direction, and the material passes through the sintering furnace in a spiral downward direction.

5. The sintering method according to claim 1, characterized in that, The air flow rate when gas is introduced into the sintering furnace is a, the mass flow rate when the material to be sintered is added to the sintering furnace is b, the percentage of metallic manganese in the material to be sintered is x%, a≥1.3bx%, where x% is 45%-90%.

6. The sintering method according to claim 5, characterized in that, The velocity of the rising airflow is 1 m / s - 2 m / s.

7. The sintering method according to claim 1, characterized in that, The material passes through the discharge pipe in a downward-sloping direction.

8. The sintering method according to claim 1, characterized in that, When the material passes through the discharge pipe, it is first cooled by direct air blowing, and then cooled by heat exchange through a cooling medium.

9. The sintering method according to claim 1, characterized in that, It also includes the following steps: S4. Cooling and dust removal: The dust-laden gas discharged from the sintering furnace and / or discharge pipe is cooled and dust removed to obtain clean gas. The clean gas is sent into the sintering furnace to blow the sintered material and / or the clean gas is sent into the discharge pipe to cool the sintered material.

10. The sintering method according to claim 1, characterized in that, The material to be sintered is manganese, and the gas is air.

Images