Production method for synthesizing silicon nitride through granulation combustion

Abstract

The invention discloses a production method for synthesizing silicon nitride through granulation combustion, which comprises the following steps: raw material pretreatment: selecting high-purity silicon powder and nitrogen as main raw materials, carrying out fine screening and impurity removal treatment on the silicon powder, innovating a granulation process: preparing the treated silicon powder into spherical particle groups with specific particle sizes by adopting a novel spray granulation technology, through accurate control of spray parameters and intelligent combustion synthesis, granulated silicon powder particles are placed in an advanced reaction container, nitrogen is introduced, and the reaction container is equipped with an intelligent temperature and pressure control system, so that reaction parameters can be monitored and adjusted in real time, and efficient product collection can be realized; and collecting and cooling the synthesized silicon nitride by using a cyclone separation technology. Through the steps of raw material treatment, granulation process innovation, intelligent combustion synthesis and the like, silicon nitride is produced, the purity of the raw materials and the reaction stability are improved, energy consumption is reduced, waste is treated in an environment-friendly mode, and an advanced and reliable method is provided for silicon nitride production.

Description

Technical Field

[0001] The invention relates to the technical field of silicon nitride synthesis, and in particular to a production method for synthesizing silicon nitride by granulation combustion. Background Art

[0002] In the modern industrial field, silicon nitride, as an important high-performance ceramic material, has attracted much attention due to its excellent performance. It has many advantages such as high strength, high hardness, high temperature resistance, corrosion resistance, and oxidation resistance, and has broad application prospects in many fields such as machinery, electronics, chemical industry, aerospace, etc.

[0003] Traditional silicon nitride preparation methods have some shortcomings. For example, some methods have complex preparation processes and require harsh conditions such as high temperature and high pressure, which not only consumes a lot of energy, but also has strict requirements on equipment, increasing production costs. At the same time, traditional methods also need to be improved in terms of product purity and quality stability. During the production process, it is often difficult to accurately control the reaction conditions, resulting in certain fluctuations in product performance.

[0004] In addition, the traditional preparation method has high requirements for raw materials, requiring high-purity silicon powder and other raw materials, and the purification process of raw materials is also relatively complicated and expensive. During the reaction process, the collection and separation of products also face some difficulties, and problems such as low product purity and low recovery rate are prone to occur. Moreover, the impact of traditional methods on the environment cannot be ignored. If the waste gas and waste residue generated during the production process are not handled properly, it will cause pollution to the environment.

[0005] With the continuous advancement of science and technology and the needs of industrial development, people have put forward higher requirements for the preparation method of silicon nitride. On the one hand, a more efficient and energy-saving preparation method is needed to reduce production costs and improve production efficiency. On the other hand, it is necessary to be able to accurately control the reaction conditions to ensure the quality and performance of the product. At the same time, it is also necessary to pay attention to environmental protection and reduce pollution to the environment.

[0006] In this context, a production method of granulated combustion synthesis of silicon nitride came into being. This method improves the purity and quality of raw materials by fine screening and pretreatment of raw materials. The innovative granulation process makes the silicon powder particles more uniform, which is conducive to the reaction. In the intelligent combustion synthesis process, the advanced temperature and pressure control system is used, combined with multi-zone heating and microwave-assisted heating technology, to accurately control the reaction conditions and improve the synthesis efficiency and quality of silicon nitride. The efficient product collection system and strict quality inspection system ensure the purity and performance of the product. Environmental protection treatment measures effectively reduce pollution to the environment. This new production method provides a more advanced and reliable solution for the preparation of silicon nitride. Summary of the invention

[0007] The present invention provides a production method of granulated combustion synthesized silicon nitride to solve the problems mentioned in the above-mentioned prior art.

[0008] In order to achieve the above object, the present invention adopts the following technical scheme: a production method of granulation combustion synthesis silicon nitride, comprising the following steps:

[0009] Raw material pretreatment: Select high-purity silicon powder and nitrogen as the main raw materials, and finely screen and remove impurities from the silicon powder to ensure that the silicon powder particles are uniform in size and free of impurities. Ultrasonic cleaning technology is used to remove tiny impurity particles on the surface of the silicon powder. The diameter of the silicon powder particles is controlled within the range of 10-50 microns, which improves the purity of the silicon powder and lays a good foundation for subsequent reactions.

[0010] Innovative granulation process: The new spray granulation technology is used to make the treated silicon powder into spherical particles of a specific particle size. By precisely controlling the spray parameters, such as spray pressure of 0.5-1.5MPa, flow rate of 10-20L / min, and angle of 30-60 degrees, the silicon powder particles are tightly combined to form a uniform particle structure. At the same time, a specific binder is added during the granulation process, which accounts for 3%-5% of the mass of the silicon powder to enhance the strength and stability of the particles.

[0011] Intelligent combustion synthesis: The granulated silicon powder particles are placed in an advanced reaction vessel and nitrogen is introduced. The reaction vessel is equipped with an intelligent temperature and pressure control system that can monitor and adjust the reaction parameters in real time. Multi-zone heating technology is used to ensure uniform distribution of reaction temperature and improve the synthesis efficiency and quality of silicon nitride. The combustion synthesis reaction temperature is controlled in the range of 1400-1600 degrees Celsius, and the pressure is precisely adjusted according to the reaction requirements, with a pressure range of 0.1-0.5MPa. In the combustion synthesis process, microwave-assisted heating technology is introduced with a microwave power of 5-10kW to accelerate the reaction process and reduce reaction energy consumption.

[0012] Efficient product collection: After the reaction is completed, the synthesized silicon nitride is collected and cooled using cyclone separation technology. The collection device is equipped with a multi-stage filtration and purification system to effectively remove impurities and unreacted silicon powder in the product, ensuring that the collected silicon nitride product is of high purity and good quality. The product purity is not less than 98%. At the same time, vacuum packaging technology is used to package the silicon nitride product to prevent the product from moisture and oxidation.

[0013] Environmental treatment: Environmental treatment is carried out on the waste gas and waste residue generated during the production process. The waste gas is discharged in compliance with the standards after purification, and the content of harmful substances in the waste gas is lower than the specific standards. The waste residue is recycled or safely disposed of to reduce pollution to the environment.

[0014] Furthermore, the particle size of the silicon powder is controlled within the range of 10-50 microns to ensure the granulation effect and the stability of the combustion synthesis reaction. At the same time, the purity of the silicon powder is not less than 99.9% to ensure the quality of the silicon nitride product.

[0015] Furthermore, the binder in the novel spray granulation technology is an environmentally friendly binder, has good bonding performance and high temperature resistance, and does not produce harmful substances during the combustion synthesis process. The binder accounts for 3%-5% of the mass of the silicon powder.

[0016] Furthermore, the intelligent temperature and pressure control system can automatically adjust parameters according to the reaction progress to ensure that the reaction is carried out under optimal conditions. The combination of multi-zone heating technology and microwave-assisted heating technology allows the reaction temperature to be controlled within the range of 1400-1600 degrees Celsius, and the pressure is precisely adjusted according to the reaction requirements, with a pressure range of 0.1-0.5MPa.

[0017] Furthermore, the cyclone separation technology and multi-stage filtration purification system can efficiently collect silicon nitride products, improve the purity and recovery rate of the products. The product purity is not less than 98%. The vacuum packaging technology can effectively protect silicon nitride products and extend the shelf life of the products.

[0018] Furthermore, the environmental protection treatment system can effectively treat waste gas and waste residue to reduce environmental pollution. The content of harmful substances in the waste gas is lower than a specific standard, and the waste residue is recycled or safely disposed of. At the same time, by optimizing the production process, reducing energy consumption and waste emissions, green production is achieved.

[0019] Furthermore, a real-time monitoring system is set up throughout the production process to continuously monitor the key indicators of silicon powder particle size, spray granulation parameters, combustion synthesis temperature and pressure, and product collection purity, and transmit the data to the central control system so that production parameters can be adjusted in a timely manner to ensure the stability of the production process and product quality. The monitoring frequency is not less than once a minute, and the data transmission delay does not exceed 1 second.

[0020] Furthermore, the purity of nitrogen is strictly controlled, and the purity of nitrogen is not less than 99.99% to ensure the efficient combustion synthesis reaction. During the nitrogen transportation process, multi-stage filtering and drying devices are used to remove impurities and moisture in the nitrogen to ensure the stability of nitrogen quality.

[0021] Furthermore, in the design of the reaction vessel, special high temperature resistant and corrosion resistant materials are used, which can withstand the high temperature of 1400-1600 degrees Celsius and the chemical corrosion during the synthesis of silicon nitride. The inner wall of the reaction vessel is specially treated to reduce the adhesion of the product on the inner wall of the container and improve the recovery rate of the product.

[0022] Furthermore, a strict quality inspection system is established to conduct comprehensive physical and chemical property inspections on the silicon nitride products produced. Inspection items include hardness, density, thermal conductivity, and chemical composition to ensure that the products meet relevant standards and customer requirements. The inspection frequency is at least one comprehensive inspection per batch of products.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention selects high-purity silicon powder and nitrogen through raw material pretreatment, and performs fine screening, impurity removal and ultrasonic cleaning on the silicon powder, so as to control the diameter of the silicon powder particles within the range of 10-50 microns, thereby ensuring the purity of the raw materials and the uniformity of the particles, and laying the foundation for the subsequent high-quality silicon nitride synthesis.

[0025] By using spray granulation technology, precisely controlling spray parameters and adding specific binders, silicon powder is made into spherical particles of specific particle size, which improves the granulation effect and reaction stability. The binder composition is designed to be environmentally friendly and harmless, and no harmful substances will be produced during the combustion synthesis process, which meets environmental protection requirements.

[0026] During the intelligent combustion synthesis process, the reaction vessel is equipped with an intelligent temperature and pressure control system. Combined with multi-zone heating technology and microwave-assisted heating technology, the reaction temperature is controlled in the range of 1400-1600 degrees Celsius, and the pressure is precisely adjusted in the range of 0.1-0.5MPa, which improves the synthesis efficiency and quality of silicon nitride while reducing the reaction energy consumption.

[0027] In the efficient product collection process, cyclone separation technology and multi-stage filtration purification system are used to effectively remove impurities and unreacted silicon powder in the product, so that the product purity is not less than 98%, which improves the purity and recovery rate of the product. Vacuum packaging technology protects silicon nitride products and extends the shelf life of the product.

[0028] The environmental protection treatment system effectively treats waste gas and waste residue, reducing pollution to the environment. At the same time, a real-time monitoring system is set up throughout the production process to continuously monitor key indicators and transmit them to the central control system, so as to facilitate timely adjustment of production parameters and ensure the stability of the production process and product quality. Strict control of nitrogen purity and the use of silicon carbide materials for reaction vessels further improve production reliability and product quality. A strict quality inspection system is established to ensure that the products meet relevant standards and customer needs. In short, the production method of the present invention provides a strong guarantee for the efficient and environmentally friendly production of silicon nitride. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic block diagram of a production method for granulated combustion synthesized silicon nitride proposed in this patent. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise" and "counterclockwise" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, and it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0033] Reference Figure 1 :The present invention provides an advanced production method of granulated combustion synthesized silicon nitride, which achieves efficient, high-quality and environmentally friendly silicon nitride production through multiple carefully designed steps.

[0034] First, we carefully select high-purity silicon powder and nitrogen as the main raw materials. The selection of silicon powder is extremely strict to ensure that it has extremely high purity, not less than 99.9%. Such high-purity silicon powder lays a solid foundation for the subsequent synthesis of high-quality silicon nitride.

[0035] Next, the silicon powder is finely screened and impurity-removed. Advanced screening equipment is used to accurately remove silicon powder that does not meet the particle size requirements, ensuring that the silicon powder particle size is uniformly controlled within the range of 10-50 microns. Silicon powder in this size range can play the best role in subsequent granulation and combustion synthesis reactions, ensuring the stability of the reaction.

[0036] In order to further improve the purity of silicon powder, ultrasonic cleaning technology is used to remove tiny impurity particles on the surface of silicon powder. The high-frequency vibration of ultrasound can effectively separate the tiny impurities attached to the surface of silicon powder, greatly improving the purity of silicon powder and creating good conditions for subsequent reactions.

[0037] The present invention adopts a new type of spray granulation technology, which can make the treated silicon powder into spherical particles of a specific particle size. In the spray granulation process, the quality of the particles can be strictly controlled by accurately controlling the spray parameters. The spray pressure is set between 0.5-1.5MPa to ensure that the silicon powder can be sprayed out and formed into particles at a suitable speed. The flow rate is controlled at 10-20 liters / minute to ensure a stable supply of silicon powder. The spray angle is adjusted to 30-60 degrees, so that the silicon powder can be evenly distributed in the space to form a uniform particle structure.

[0038] At the same time, a specific binder is added during the granulation process. This binder is an environmentally friendly binder with good bonding performance and high temperature resistance. During the combustion synthesis process, no harmful substances are produced, ensuring the environmental protection of the production process. The binder accounts for 3%-5% of the mass of the silicon powder. This ratio has been carefully optimized to ensure the strength and stability of the silicon powder particles without adversely affecting the reaction.

[0039] The granulated silicon powder particles are placed in an advanced reaction vessel. This reaction vessel is carefully designed and equipped with an intelligent temperature and pressure control system. The system can monitor the temperature and pressure during the reaction in real time and automatically adjust the parameters according to the progress of the reaction to ensure that the reaction is carried out under optimal conditions.

[0040] Multi-zone heating technology is used to make the temperature in the reaction vessel evenly distributed. This technology can avoid local temperatures that are too high or too low, and improve the synthesis efficiency and quality of silicon nitride. The combustion synthesis reaction temperature is strictly controlled in the range of 1400-1600 degrees Celsius. This temperature range is the optimal reaction temperature range verified by a large number of experiments. The pressure is precisely adjusted according to the reaction requirements, and the pressure range is 0.1-0.5MPa. In the combustion synthesis process, microwave-assisted heating technology is introduced, and the microwave power is 5-10kW. Microwave-assisted heating can accelerate the reaction process, reduce the reaction time, and at the same time reduce the reaction energy consumption and improve production efficiency.

[0041] After the reaction is completed, the synthesized silicon nitride is collected and cooled using cyclone separation technology. The cyclone separation technology can quickly separate the silicon nitride particles from the reaction products and cool them, avoiding overheating and oxidation of the products.

[0042] The collection device is equipped with a multi-stage filtration and purification system. These systems can effectively remove impurities and unreacted silicon powder in the product, ensuring that the collected silicon nitride product is of high purity and good quality. The product purity is not less than 98%, reaching the high standard in the industry.

[0043] At the same time, vacuum packaging technology is used to package silicon nitride products. Vacuum packaging can effectively prevent the product from moisture and oxidation, extend the shelf life of the product, and ensure the stability of product quality during storage and transportation.

[0044] The present invention pays great attention to environmental protection, and the waste gas and waste residue generated in the production process are treated in an environmentally friendly manner. The waste gas is discharged in compliance with the standards after purification, and the content of harmful substances in the waste gas is lower than the specific standard. The use of advanced waste gas purification equipment can effectively remove harmful substances in the waste gas and reduce pollution to the environment.

[0045] Waste residues are recycled or safely disposed of. For recyclable waste residues, they are classified and reprocessed to achieve resource recycling. For non-recyclable waste residues, safe disposal methods are used to ensure that they will not cause harm to the environment.

[0046] At the same time, we optimize the production process, reduce energy consumption and waste emissions, and achieve green production. Throughout the production process, we continuously optimize the process parameters of each link, improve energy efficiency, reduce waste generation, and contribute to environmental protection.

[0047] A real-time monitoring system is set up throughout the production process to continuously monitor key indicators such as the size of silicon powder particles, spray granulation parameters, combustion synthesis temperature and pressure, and product collection purity. The monitoring frequency is no less than once a minute to ensure that any abnormal situation in the production process can be discovered in time. The data transmission delay does not exceed 1 second, ensuring that the central control system can obtain the latest monitoring data in a timely manner and make corresponding adjustments.

[0048] The purity of nitrogen is strictly controlled, and the purity of nitrogen is not less than 99.99%. During the nitrogen transportation process, multi-stage filtering and drying devices are used to remove impurities and moisture in nitrogen to ensure the stability of nitrogen quality. High-purity nitrogen can ensure the efficient combustion synthesis reaction and improve the quality of silicon nitride.

[0049] The reaction vessel is designed with special high temperature and corrosion resistant materials that can withstand high temperatures of 1400-1600 degrees Celsius and chemical corrosion during the synthesis of silicon nitride. The inner wall of the reaction vessel is specially treated to reduce the adhesion of the product on the inner wall of the container and improve the recovery rate of the product.

[0050] We have established a strict quality inspection system to conduct comprehensive physical and chemical property tests on the silicon nitride products we produce. The inspection items include hardness, density, thermal conductivity, chemical composition, etc. to ensure that the products meet relevant standards and customer needs. The inspection frequency is at least one comprehensive inspection per batch of products to ensure the stability and reliability of product quality.

[0051] Embodiment 1:

[0052] Silicon powder with a purity of 99.95% is selected as the raw material, and the silicon powder is finely screened using professional screening equipment to remove larger and smaller particles to ensure that the diameter of the silicon powder particles is within the range of 20-40 microns. Then, ultrasonic cleaning technology is used to clean the silicon powder at a specific frequency to remove tiny impurity particles on the surface.

[0053] In the granulation process, a new type of spray granulation equipment is used, and the spray pressure is set to 1MPa, the flow rate is 15 liters / minute, and the angle is 45 degrees to make the treated silicon powder into spherical particles. At the same time, a binder consisting of 35% esterified starch, 25% sodium carboxymethyl cellulose, 25% guar gum and 15% silicone defoamer is added, and the binder accounts for 4% of the mass of the silicon powder.

[0054] The granulated silicon powder particles are placed in a reaction vessel made of silicon carbide material, and the inner wall is specially treated to prevent adhesion. Nitrogen with a purity of 99.99% is introduced, and the intelligent temperature and pressure control system is started. Multi-zone heating is set to stabilize the temperature at around 1500 degrees Celsius, and the pressure is adjusted to 0.3MPa. At the same time, microwave assisted heating is turned on, and the microwave power is set to 8kW.

[0055] After the reaction is completed, the product is collected using cyclone separation technology and multi-stage filtration purification system, and the product purity reaches 98.5%. Finally, the product is packaged using vacuum packaging technology. During the production process, the real-time monitoring system monitors various key indicators once a minute, and the data is transmitted to the central control system. Each batch of products undergoes comprehensive physical and chemical performance testing.

[0056] Embodiment 2:

[0057] Silicon powder with a purity of 99.9% is selected and strictly screened and treated to keep the particle diameter of the silicon powder at 15-45 microns. After ultrasonic cleaning to remove impurities, granulation is carried out.

[0058] During the spray granulation, the spray pressure was set to 0.8 MPa, the flow rate was 18 L / min, the angle was 50 degrees, and a binder accounting for 3.5% of the mass of the silicon powder was added. The binder composition was the same as that in Example 1.

[0059] The granulated silicon powder is placed in a reaction vessel, which is also made of silicon carbide with a specially treated inner wall. High-purity nitrogen (99.995%) is introduced, and the intelligent control system controls the reaction temperature at 1450 degrees Celsius, the pressure at 0.25 MPa, and the microwave-assisted heating power at 7 kW.

[0060] The product is collected using cyclone separation technology and a multi-stage filtration purification system, with a product purity of 98.2%. It is vacuum packaged and the waste gas and waste residue are treated by an environmental protection treatment system. The real-time monitoring system works continuously, and each batch of products is tested for hardness, density, thermal conductivity and chemical composition.

[0061] Embodiment three:

[0062] Silicon powder with a purity of 99.92% is selected for fine screening and impurity removal, and the particle diameter of the silicon powder is controlled at 25-45 microns. After ultrasonic cleaning, granulation is carried out.

[0063] During the granulation process, the spray pressure was set to 1.2 MPa, the flow rate was 12 liters / minute, the angle was 40 degrees, and a binder accounting for 4.5% of the mass of the silicon powder was added.

[0064] The silicon powder particles are placed in a reaction vessel made of silicon carbide with a specially treated inner wall. Nitrogen with a purity of 99.992% is introduced, and the intelligent control system sets the temperature to 1550 degrees Celsius, the pressure to 0.4MPa, and the microwave-assisted heating power to 9kW.

[0065] The purity of the product after collection is 98.8%, and the product is vacuum packaged. Environmentally friendly treatment of waste gas and waste residue, real-time monitoring system and strict quality inspection system ensure product quality. Each batch of products is fully tested.

[0066] The following is a comparison table designed for the three embodiments:

[0067]

[0068]

[0069] All three embodiments use high-purity silicon powder with a purity of 99.9% or above, ensuring a high-quality starting point for silicon nitride products. Different particle diameter ranges affect the granulation effect and subsequent reactions to a certain extent, but they are all within a reasonable range, ensuring the stability of the reaction.

[0070] The spray pressure, flow rate and angle are different in the three embodiments, but they can all make the silicon powder particles closely combined to form a uniform structure. The difference in the proportion of the binder has no significant effect on the strength and stability of the particles, and all can meet the production requirements.

[0071] The reaction temperature, pressure and microwave power have their own characteristics in the three embodiments. The changes in temperature and pressure have a certain impact on the synthesis efficiency and quality of silicon nitride, but they are all controlled within a suitable range to ensure the smooth progress of the reaction. The degree of acceleration of the reaction process by different microwave powers is slightly different, but they all play a role in reducing the reaction energy consumption.

[0072] The purity of the products of the three embodiments is not less than 98%, and although the specific values ​​are different, they all reach a relatively high standard, which shows that different combinations of process parameters can produce high-quality silicon nitride products.

[0073] The purity of nitrogen is no less than 99.99%, ensuring the efficient combustion synthesis reaction. The monitoring frequency is once a minute, ensuring the stability of the production process and the controllability of product quality.

[0074] In general, although there are some differences in specific process parameters in the three embodiments, they can all produce high-quality and high-purity silicon nitride products through the granulation combustion synthesis silicon nitride production method of the present invention. Different parameter combinations provide multiple options for actual production, which can be adjusted and optimized according to specific production requirements and conditions.

[0075] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can replace or change the technical solution and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for producing silicon nitride by granulation combustion synthesis, characterized in that: The following steps are involved: Raw material pretreatment: high-purity silicon powder and nitrogen are selected as the main raw materials, and the silicon powder is finely screened and impurity-removed. The silicon powder particles are uniform in size and free of impurities. Ultrasonic cleaning technology is used to remove tiny impurity particles on the surface of the silicon powder. The diameter of the silicon powder particles is controlled within the range of 10-50 microns; Granulation process: Spray granulation technology is used to make the treated silicon powder into spherical particles of a specific particle size. The spray parameters are precisely controlled, including spray pressure of 0.5-1.5MPa, flow rate of 10-20L / min, and angle of 30-60 degrees. A binder is added during the granulation process, and the binder accounts for 3%-5% of the mass of the silicon powder. Intelligent combustion synthesis: The granulated silicon powder particles are placed in an advanced reaction vessel and nitrogen is introduced. The reaction vessel is equipped with an intelligent temperature and pressure control system and adopts multi-zone heating technology. The combustion synthesis reaction temperature is controlled in the range of 1400-1600 degrees Celsius. The pressure is adjusted according to the reaction requirements, and the pressure range is 0.1-0.5MPa. In the combustion synthesis process, microwave-assisted heating technology is introduced, and the microwave power is 5-10kW; Efficient product collection: After the reaction is completed, the synthesized silicon nitride is collected and cooled using cyclone separation technology. The collection device is equipped with a multi-stage filtration and purification system to remove impurities and unreacted silicon powder in the product. The product purity is not less than 98%, and the silicon nitride product is packaged using vacuum packaging technology; Environmental protection treatment: The waste gas and waste residue generated in the production process are treated in an environmentally friendly manner, and the waste gas is discharged after purification.

2. The method for producing silicon nitride by granulation combustion synthesis according to claim 1, characterized in that: The particle size of the silicon powder is controlled within the range of 10-50 microns, and the purity of the silicon powder is not less than 99.9%.

3. The method for producing silicon nitride by granulation combustion synthesis according to claim 1, characterized in that: The binder in the spray granulation technology is composed of the following materials in the following mass ratio: 30%-40% esterified starch, 20%-30% sodium carboxymethyl cellulose, 20%-30% guar gum or gum arabic, 5%-10% organic silicon defoamer, no harmful substances are generated in the combustion synthesis process, and the binder accounts for 3%-5% of the mass of silicon powder.

4. The method for producing silicon nitride by granulation combustion synthesis according to claim 1, characterized in that: The intelligent temperature and pressure control system can automatically adjust parameters according to the reaction progress. The combination of multi-zone heating technology and microwave-assisted heating technology can control the reaction temperature within the range of 1400-1600 degrees Celsius, and the pressure is accurately adjusted according to the reaction requirements, with a pressure range of 0.1-0.5MPa.

5. The method for producing silicon nitride by granulation combustion synthesis according to claim 1, characterized in that: The cyclone separation technology and multi-stage filtration purification system collect silicon nitride products, improve the purity and recovery rate of the products, and the product purity is not less than 98%. The vacuum packaging technology protects the silicon nitride products and extends the shelf life of the products.

6. The method for producing silicon nitride by granulation combustion synthesis according to claim 1, characterized in that: The environmental protection treatment system effectively treats waste gas and waste residue to reduce pollution to the environment, and the waste residue is recycled or safely disposed of.

7. The method for producing silicon nitride by granulation combustion synthesis according to claim 1, characterized in that: A real-time monitoring system is set up throughout the entire production process to continuously monitor the key indicators of silicon powder particle size, spray granulation parameters, combustion synthesis temperature and pressure, and purity of product collection. The data is transmitted to the central control system for adjusting production parameters. The monitoring frequency is not less than once a minute, and the data transmission delay does not exceed 1 second.

8. The method for producing silicon nitride by granulation combustion synthesis according to claim 1, characterized in that: The purity of nitrogen is strictly controlled, and the purity of nitrogen is not less than 99.99%. During the nitrogen transportation process, multi-stage filtering and drying devices are used to remove impurities and moisture in the nitrogen.

9. The method for producing silicon nitride by granulation combustion synthesis according to claim 1, characterized in that: The reaction vessel is designed with silicon carbide material, which can withstand high temperatures of 1400-1600 degrees Celsius and chemical corrosion during the synthesis of silicon nitride. The inner wall of the reaction vessel is specially treated to reduce the adhesion of the product on the inner wall of the container and improve the recovery rate of the product.

10. The method for producing silicon nitride by granulation combustion synthesis according to claim 1, characterized in that: A strict quality inspection system is established to conduct comprehensive physical and chemical property tests on the silicon nitride products produced. The inspection items include hardness, density, thermal conductivity, and chemical composition. The inspection frequency is at least one comprehensive inspection for each batch of products.

Images