Silicon carbide smelting process based on spent material charging of closed negative-pressure downward-jumping type smelting furnace

Abstract

The invention belongs to the technical field of silicon carbide material production, and discloses a silicon carbide smelting process based on spent material charging in a closed negative-pressure jump-down smelting furnace, which comprises the following steps: step 1, after smelting waste spent materials are crushed by a jaw crusher, screening is carried out by a vibrating screen with the aperture of 5mm to obtain spent material particles with the particle size of not more than 5mm; step 2, doping a sawdust swelling agent into the spent material particles, wherein the doping amount is 3-5% of the total weight of the spent material; and 3, supplementing anthracite and quartz sand into the mixture, and adjusting the content of fixed carbon to 15-20% and the content of silicon dioxide to 60-65%. By forming the high-activity regenerated mixture, the porosity and air permeability of the material are reconstructed through the design, residual carbon and silicon elements efficiently participate in a combination reaction in a core reaction area, negative pressure fluctuation caused by gas retardation is synchronously eliminated, the resource recycling rate is fundamentally increased, and new material consumption and solid waste emission are remarkably reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicon carbide material production, and specifically relates to a silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace. Background Art

[0002] Silicon carbide smelting mainly adopts the high-temperature synthesis process of resistance furnace. Traditional smelting furnace types (such as open or semi-closed furnaces) use graphite electrodes to heat the mixture of quartz sand and anthracite to react and generate silicon carbide crystals. During the smelting process, the materials in the furnace are laid out in layers, with coke or graphite laid on the bottom as a conductive layer, and the upper part covered with a layer of reaction materials. In order to control the atmosphere and temperature in the furnace, some technologies use negative pressure operation to reduce the mixing of impurity gases, and achieve continuous production through a fixed furnace loading structure. The spent material generated after smelting (the main component is a mixture of unreacted coal and quartz sand) is usually treated as waste and piled up, accounting for about 2%-5%. In the existing technology, spent materials are only used for limited use in the thermal insulation layer at the bottom of the furnace or as auxiliary laying on the periphery of new materials, and do not participate in the reaction process in the core reaction zone.

[0003] The traditional process has the following main problems: low resource utilization: the spent material has a dense structure and reduced activity after high-temperature sintering. Directly loading it into the furnace will hinder the discharge of gases (such as carbon monoxide), resulting in pressure fluctuations and uneven reactions in the furnace. The existing technology does not solve the problem of physical property adaptation of spent materials, and they are forced to be discarded, resulting in the waste of thousands of tons of effective raw materials every year.

[0004] Energy consumption and pollution issues: Open furnaces cannot be completely sealed during smelting, and harmful gases (such as CO) escape, requiring an additional exhaust gas treatment system. At the same time, the flat-layer material distribution method leads to low heat transfer efficiency in the furnace, and the unit power consumption of the product is as high as 5900kWh / ton. In addition, the consumption of new materials (anthracite, quartz sand) remains high.

[0005] Insufficient process compatibility: Although the leap-type smelting furnace enhances mixing efficiency through material drop, the existing furnace loading process does not fully utilize its structural advantages. If the spent material is directly added to the reaction zone, the dense structure will hinder the airflow channel and affect the negative pressure stability. If it is only used in the non-reaction zone, the residual carbon and silicon elements in it cannot be recovered, and the technical and economic benefits are difficult to achieve. Summary of the Invention

[0006] The object of the present invention is to provide a silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace, so as to solve the problems raised in the above background technology.

[0007] In order to achieve the above object, the present invention provides the following technical solution: a silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace, comprising the following steps:

[0008] Step 1: crush the smelting waste by jaw crusher, and then sieve it through a 5mm aperture vibration screen to obtain waste particles with a particle size not exceeding 5mm;

[0009] Step 2: Add sawdust bulking agent to the waste material particles, the amount of which is 3% to 5% of the total weight of the waste material;

[0010] Step 3: Add anthracite and quartz sand to the mixture to adjust the fixed carbon content to 15% to 20% and the silica content to 60% to 65%;

[0011] Step 4: Spread the mixture and air-dry it until the moisture content is less than 2% to form a recycled mixture;

[0012] Step 5: Lay a waste PO film insulation layer on the bottom of the jump smelting furnace, and cover it with a 20 cm thick quartz sand layer;

[0013] Step 6: Fill the recycled mixture on top of the quartz sand layer to a thickness of 110 cm, and lay a 30 cm thick layer of wood and a 20 cm thick layer of spent material-anthracite mixture on top;

[0014] Step 7: Use low-quality graphite to build a furnace core with a size of 100 cm by 80 cm. Fill the outer surface of the furnace core with an anthracite-quartz sand mixture.

[0015] Step 8: Fill the upper part of the core reaction zone with recycled mixed material to a thickness of 60 cm, and add 30 shovels of sawdust with each batch of material;

[0016] Step 9: Start the fully enclosed negative pressure system and dynamically control the pressure in the furnace to minus 50 Pa to minus 100 Pa;

[0017] Step 10: Use a step-by-step voltage boost mode to transmit power and stabilize the core area temperature at 2,200 to 2,400 degrees Celsius.

[0018] By efficiently recycling smelting waste as the primary raw material, resource recycling is achieved, significantly reducing raw material consumption and production costs. A closed negative pressure system precisely controls environmental conditions, effectively preventing the leakage of harmful gases, optimizing the stability of the reaction process, and ensuring the efficiency and consistency of the silicon carbide production reaction. The addition of a specific bulking agent adjusts the raw material composition, enhancing the permeability of the mixture, promoting uniform diffusion at high temperatures, and reducing impurity generation, thereby improving product purity and mechanical properties. The system's temperature control and furnace layer design work synergistically to reduce heat loss, improve energy efficiency, and minimize environmental impact.

[0019] As a further technical solution of the present invention, the aperture of the vibrating screen in step one is five millimeters.

[0020] As a further technical solution of the present invention, the moisture content of the sawdust bulking agent in step 2 does not exceed 5%.

[0021] As a further technical solution of the present invention, the fixed carbon content of the low-quality graphite in step seven is greater than or equal to eighty-five percent.

[0022] As a further technical solution of the present invention, the sawdust in step eight is embedded in the recycled mixture in the form of dispersed clusters.

[0023] As a further technical solution of the present invention, the step nine monitors data in real time through an air pressure sensor and links the induced draft fan to close the loop and adjust the negative pressure value.

[0024] As a further technical solution of the present invention, the ten-step boost mode specifically includes:

[0025] Stage 1: Raise the temperature to 1,800 degrees Celsius at 20% power and maintain the temperature for 30 minutes;

[0026] Stage 2: Raise the temperature to 2,200 degrees Celsius at 60% power and maintain the temperature for 60 minutes;

[0027] Phase 3: Maintain target temperature at 100% power.

[0028] As a further technical solution of the present invention, the silicon dioxide purity of the quartz sand in step five is greater than or equal to ninety-eight percent.

[0029] As a further technical solution of the present invention, the leap-type smelting furnace is a fully sealed structure, and a circulating cooling water channel is built into the furnace wall.

[0030] The beneficial effects of the present invention are as follows:

[0031] (1) The present invention breaks through the technical bottleneck of the dense structure of traditional waste materials by regenerating waste material particles and modifying them with a fluffing agent, forming a highly active recycled mixture. This design reconstructs the porosity and permeability of the material, allowing the residual carbon and silicon elements to efficiently participate in the chemical reaction in the core reaction zone, and simultaneously eliminates the negative pressure fluctuations caused by gas blockage, fundamentally improving the resource recycling rate and significantly reducing the consumption of new materials and solid waste emissions.

[0032] (2) The present invention uses a fully enclosed negative pressure system in conjunction with a dynamic air pressure control mechanism to accurately maintain the reducing atmosphere concentration and gas migration path, effectively blocking the escape of harmful gases and the penetration of external oxidizing media, eliminating the burden of exhaust gas treatment and reducing the risk of environmental pollution. Combined with a step-by-step pressure input mode, the present invention optimizes the solid-gas reaction kinetics process, suppresses local overheating and ineffective energy consumption, and achieves a substantial reduction in the comprehensive energy consumption per unit product.

[0033] (3) The present invention is based on the structural characteristics of the leap furnace body, and innovates the layered loading and furnace core design, giving full play to the advantages of material drop mixing. The dispersed sawdust clusters and gradient paving work together to construct a stable thermal field and airflow channel, solving the contradiction between the waste material blocking the airflow and the low heat transfer efficiency in the traditional process. The circulating cooling system ensures the stable geometric accuracy of the equipment, and ensures the directional growth of high-purity silicon carbide crystals while recovering the residual elements of the waste material, thus achieving a breakthrough in technology and economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flowchart of the waste material pretreatment process of the present invention;

[0035] Figure 2 This is a schematic diagram of the furnace layering of the present invention;

[0036] Figure 3 This is a logic control diagram for process parameter regulation of the present invention;

[0037] Figure 4 This is a data experiment diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0039] like Figures 1 to 4 As shown, in an embodiment of the present invention, a silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace comprises the following steps:

[0040] Step 1: crush the smelting waste by jaw crusher, and then sieve it through a 5mm aperture vibration screen to obtain waste particles with a particle size not exceeding 5mm;

[0041] Step 2: Add sawdust bulking agent to the waste material particles, the amount of which is 3% to 5% of the total weight of the waste material;

[0042] Step 3: Add anthracite and quartz sand to the mixture to adjust the fixed carbon content to 15% to 20% and the silica content to 60% to 65%;

[0043] Step 4: Spread the mixture and air-dry it until the moisture content is less than 2% to form a recycled mixture;

[0044] Step 5: Lay a waste PO film insulation layer on the bottom of the jump smelting furnace, and cover it with a 20 cm thick quartz sand layer;

[0045] Step 6: Fill the recycled mixture on top of the quartz sand layer to a thickness of 110 cm, and lay a 30 cm thick layer of wood and a 20 cm thick layer of spent material-anthracite mixture on top;

[0046] Step 7: Use low-quality graphite to build a furnace core with a size of 100 cm by 80 cm. Fill the outer surface of the furnace core with an anthracite-quartz sand mixture.

[0047] Step 8: Fill the upper part of the core reaction zone with recycled mixed material to a thickness of 60 cm, and add 30 shovels of sawdust with each batch of material;

[0048] Step 9: Start the fully enclosed negative pressure system and dynamically control the pressure in the furnace to minus 50 Pa to minus 100 Pa;

[0049] Step 10: Use a step-by-step voltage boost mode to transmit power and stabilize the core area temperature at 2,200 to 2,400 degrees Celsius.

[0050] By efficiently recycling smelting waste as the primary raw material, resource recycling is achieved, significantly reducing raw material consumption and production costs. A closed negative pressure system precisely controls environmental conditions, effectively preventing the leakage of harmful gases, optimizing the stability of the reaction process, and ensuring the efficiency and consistency of the silicon carbide production reaction. The addition of a specific bulking agent adjusts the raw material composition, enhancing the permeability of the mixture, promoting uniform diffusion at high temperatures, and reducing impurity generation, thereby improving product purity and mechanical properties. The system's temperature control and furnace layer design work synergistically to reduce heat loss, improve energy efficiency, and minimize environmental impact.

[0051] Among them, the aperture of the vibrating screen in step one is five millimeters.

[0052] The screened waste material particles can achieve precise particle size control to ensure full contact between the material reaction interface, avoid large particle blockage or fine powder encapsulation, thereby optimizing the reaction kinetics efficiency and simultaneously ensuring the homogeneity and air permeability of the recycled mixture, creating basic conditions for gas-solid mass transfer in the high-temperature smelting stage, and significantly improving the purity of silicon carbide crystals and product performance.

[0053] Wherein, the moisture content of the sawdust bulking agent in step 2 does not exceed 5%.

[0054] This control ensures that the bulking agent expands instantaneously at high temperatures to form a stable pore structure, preventing the air pressure disturbance caused by water vaporization from destroying the closed negative pressure environment. At the same time, it inhibits the gasification reaction between water vapor and carbonaceous raw materials to consume the effective carbon source, ensuring the precise ratio of carbon and silicon elements to react. By eliminating the interference of free water, the purity of the reaction atmosphere in the core area is maintained, and the integrity of silicon carbide crystal growth is effectively improved.

[0055] Wherein, the fixed carbon content of the low-quality graphite in step seven is greater than or equal to 85%.

[0056] This control ensures that the furnace core has high electrical conductivity and heat-resistant skeleton characteristics, can fully withstand ultra-high temperature thermal shock without breaking, and continuously and stably transmits energy to the core reaction area. At the same time, it provides sufficient activated carbon source to participate in the carbon-silicon replacement reaction, suppresses the under-reduction problem caused by insufficient carbon, and maintains the purity and fluidity of the melt by avoiding the gasification of low fixed carbon impurities to form bubbles or ash, ultimately ensuring the complete and uniform directional growth of silicon carbide crystals.

[0057] The sawdust in step eight is embedded in the recycled mixture in the form of dispersed clusters.

[0058] The dispersed layout of sawdust forms a gradient decomposition channel network, which promotes the simultaneous production of controllable volatiles when organic matter is heated at high temperature, guides the reaction interface to form a uniform microporous structure, enhances the directional diffusion ability of gaseous reactants, and optimizes the progressive supply efficiency of carbonaceous reducing agents. This structural design weakens the instantaneous carbon concentration fluctuations in the high-temperature zone, inhibits local over-reduction or carbon deposition, ensures the continuous and stable growth of silicon carbide crystals in a solid-gas balance environment, and simultaneously improves energy utilization.

[0059] Among them, step nine monitors the data in real time through the air pressure sensor, and links the induced draft fan to close the loop to adjust the negative pressure value.

[0060] Real-time closed-loop control accurately maintains the stability of the reducing gas environment, blocks the penetration of external oxidizing media and optimizes the directional migration of reaction gases. This dynamic balance mechanism effectively suppresses abnormal condensation of silicon vapor and the occurrence of side reactions, ensuring that the carbon and silicon elements are fully combined under thermodynamic equilibrium conditions. By accurately eliminating interference from gas pressure fluctuations, it ensures the continuous stability of the crystal growth interface, significantly improves the integrity of the silicon carbide crystal form and the product conversion rate, and simultaneously reduces non-productive energy losses.

[0061] The ten-step boost mode specifically includes:

[0062] Stage 1: Raise the temperature to 1,800 degrees Celsius at 20% power and maintain the temperature for 30 minutes;

[0063] Stage 2: Raise the temperature to 2,200 degrees Celsius at 60% power and maintain the temperature for 60 minutes;

[0064] Phase 3: Maintain target temperature at 100% power.

[0065] Through the energy gradient input design, the smooth evolution of the material structure is first achieved to avoid the concentrated release of volatiles leading to the risk of explosion. Secondly, an orderly rupture mechanism of solid-state silicon-oxygen bonds is established to drive the deep penetration of carbon-silicon heterogeneous reactions, and ultimately achieve coordinated control of crystal nucleation and growth rates, effectively suppressing melt overheating expansion and secondary crystal defects, while reducing thermal shock losses and ensuring the integrity of the directional arrangement of high-purity silicon carbide crystals.

[0066] In step five, the silica purity of the quartz sand is greater than or equal to 98%.

[0067] The high-purity quartz sand builds a stable chemical inert barrier, effectively blocks the risk of melt leakage and furnace bottom metal corrosion, and at the same time guarantees the uniformity of heat transfer in a high-temperature environment, avoids impurities causing local hot spots or thermal shock burst, and the consistent composition provides a reliable supporting framework for the reaction zone, inhibits the interference of amorphous substances caused by side reactions, and finally ensures the uniform growth of silicon carbide crystals in a low-pollution environment and maintains the structural integrity.

[0068] The jump smelting furnace is a fully sealed structure, and the circulating cooling water channel is built into the furnace wall.

[0069] The design forms a rigid thermal boundary isolation system, and the cooling water channel continuously leads out the heat storage of the furnace wall to inhibit high-temperature creep deformation, guarantee the reliability of the whole cycle sealing, and at the same time block the disturbance of external moisture penetration to the reducing atmosphere, stabilize the silicon vapor migration path. The synergistic effect of physical isolation and heat conduction not only avoids the risk of overheating failure of the furnace body, but also ensures the uniform distribution of the furnace core thermal field, provides a reaction space with stable geometric precision for crystal directional growth, and significantly prolongs the service life of the equipment.

[0070] Embodiment:

[0071] It includes spent material pretreatment, gradient charging, and dynamic control.

[0072] Spent material pretreatment includes crushing and screening:

[0073] Take 10 tons of smelting spent material (fixed carbon content 12%, silicon dioxide 58%) and crush it with a jaw crusher;

[0074] Pass through a 5mm aperture vibrating screen to obtain 8.7 tons of particles with a particle size of ≤5mm;

[0075] Add a bulking agent:

[0076] Add pine sawdust (moisture content 3%) to the metering belt at a ratio of 4% (348kg);

[0077] Add raw materials:

[0078] Add 1.2 tons of anthracite (fixed carbon content 78%) and 1.8 tons of quartz sand (silicon dioxide purity 99%);

[0079] Mix uniformly in a double-shaft mixer, the fixed carbon content reaches 18%, and the silicon dioxide content is 63%;

[0080] Drying treatment:

[0081] Spread on a drying bed for 10948 hours, the moisture content is reduced to 1.8%, and 11.8 tons of regenerated mixture are prepared.

[0082] Gradient furnace loading: including bottom layer laying:

[0083] The furnace bottom is paved with 0.5mm thick waste PO film;

[0084] Covering with quartz sand layer (purity 99%, thickness 20cm±0.5cm);

[0085] Lower reaction zone:

[0086] Fill the recycled mixture to a thickness of 110cm;

[0087] The top is laid with a 30cm thick layer of pine wood and a 20cm layer of spent material-anthracite 207 (ratio 1:1);

[0088] Core reaction area:

[0089] The furnace core (dimensions 100 cm × 80 cm × 60 cm) was constructed using low-quality graphite (86% fixed carbon);

[0090] The outer periphery of the furnace core is filled with anthracite-quartz sand mixture 204 (ratio 6:4);

[0091] Upper spent material area:

[0092] Fill the recycled mixture to a thickness of 60cm;

[0093] 30 shovels of pine sawdust (controlled at 20 kg) were manually added to each batch of material (controlled at 1.2 tons) to form dispersed clusters with a diameter of 3-5 cm.

[0094] Dynamic regulation: including negative pressure control:

[0095] Start the induced draft fan and monitor the air pressure sensor in real time;

[0096] The negative pressure regulating module dynamically maintains the negative pressure in the furnace at 80Pa±5Pa;

[0097] Step heating:

[0098] The first stage (0-2h): 20% power to raise the temperature to 1800℃, keep the temperature constant for 30min;

[0099] The second stage (2-5h): 60% power to 2200℃, keep the temperature constant for 60min;

[0100] The third stage (5-10h): 100% power is increased to 2350℃±50℃ and maintained.

[0101] This embodiment achieves efficient activation and gradient release of residual carbon and silicon elements by systematically regenerating the physical properties of waste materials. The bulking agent accurately penetrates and reshapes the waste material stacking structure, forming a stable breathable channel to eliminate the risk of gas blockage, so that the recycled mixture has the activity of original materials in the core reaction area. The layered furnace design is differentiated according to the reaction characteristics of the materials. The bottom insulation layer blocks the ineffective dissipation of heat energy. The middle wood layer constructs a slow-release carbon source transition zone, and dispersed sawdust clusters form an in-situ pore-forming core, which synergistically improves the efficiency of the directional migration of reducing gas. The negative pressure dynamic control module balances the atmosphere concentration in real time, blocks the external oxidizing medium while ensuring the orderly extraction of by-products. The stepped energy input matches the kinetic process of each phase transformation. The stable volatile matter is slowly released in the early stage to avoid explosion, promotes the deep breakage of silicon-oxygen bonds in the middle stage, and ensures the integrity of the crystal directional arrangement in the later stage.

[0102] By recycling spent material particles and modifying them with a bulking agent, the technical bottleneck of the dense structure of traditional waste materials is broken through, forming a highly active recycled mixture. This design reconstructs the porosity and permeability of the material, allowing the remaining carbon and silicon elements to efficiently participate in the chemical reaction in the core reaction area, while simultaneously eliminating the negative pressure fluctuations caused by gas blockage, fundamentally improving the resource recycling rate and significantly reducing new material consumption and solid waste emissions.

[0103] Through the fully enclosed negative pressure system and the coordinated dynamic air pressure control mechanism, the reducing atmosphere concentration and gas migration path are accurately maintained, effectively blocking the escape of harmful gases and the penetration of external oxidizing media, eliminating the burden of exhaust gas treatment and reducing the risk of environmental pollution. Combined with the step-by-step pressure input mode, the solid-gas reaction kinetics process is optimized, local overheating and ineffective energy consumption are suppressed, and a substantial reduction in the comprehensive energy consumption per unit product is achieved.

[0104] Based on the structural characteristics of the leap-type furnace, innovative layered loading and furnace core design are adopted to fully utilize the advantages of material drop mixing. Dispersed sawdust clusters and gradient paving work together to construct a stable thermal field and airflow channel, solving the contradiction between spent materials hindering airflow and low heat transfer efficiency in traditional processes. The circulating cooling system ensures the stable geometric accuracy of the equipment, while recovering the residual elements of the spent materials and ensuring the directional growth of high-purity silicon carbide crystals, achieving a breakthrough in technology and economy.

[0105] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A closed negative pressure down-jump smelting furnace based on spent material charging for silicon carbide smelting process, characterized by: The following steps are involved: Step 1: crush the smelting waste by jaw crusher, and then pass it through a 5mm aperture vibration screen to obtain waste particles with a particle size not exceeding 5mm; Step 2: Add sawdust bulking agent to the waste material particles, the amount of which is 3% to 5% of the total weight of the waste material; Step 3: Add anthracite and quartz sand to the mixture to adjust the fixed carbon content to 15% to 20% and the silica content to 60% to 65%; Step 4: Spread the mixture and air-dry it until the moisture content is less than 2% to form a recycled mixture; Step 5: Lay a waste PO film insulation layer on the bottom of the jump smelting furnace, and cover it with a 20 cm thick quartz sand layer; Step 6: Fill the recycled mixture on top of the quartz sand layer to a thickness of 110 cm, and lay a 30 cm thick layer of wood and a 20 cm thick layer of spent material-anthracite mixture on top; Step 7: Use low-quality graphite to build a furnace core with a size of 100 cm by 80 cm. Fill the outer surface of the furnace core with an anthracite-quartz sand mixture. Step 8: Fill the upper part of the core reaction zone with recycled mixed material to a thickness of 60 cm, and add 30 shovels of sawdust with each batch of material; Step 9: Start the fully enclosed negative pressure system and dynamically control the pressure in the furnace to minus 50 Pa to minus 100 Pa; Step 10: Use a step-by-step voltage boost mode to transmit power and stabilize the core area temperature at 2,200 to 2,400 degrees Celsius.

2. The silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace according to claim 1 is characterized in that: The aperture of the vibrating screen in step 1 is five millimeters.

3. The silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace according to claim 1 is characterized in that: The moisture content of the sawdust bulking agent in step 2 does not exceed 5%.

4. The silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace according to claim 1 is characterized in that: The fixed carbon content of the low-quality graphite in step seven is greater than or equal to 85%.

5. The silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace according to claim 1 is characterized in that: The sawdust in step eight is embedded in the recycled mixture in the form of dispersed clusters.

6. The silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace according to claim 1 is characterized in that: In step nine, the air pressure sensor is used to monitor data in real time, and the induced draft fan is linked to adjust the negative pressure value in a closed loop.

7. The silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace according to claim 1 is characterized in that: The ten-step boost mode specifically includes: Stage 1: Raise the temperature to 1,800 degrees Celsius at 20% power and maintain the temperature for 30 minutes; Stage 2: Raise the temperature to 2,200 degrees Celsius at 60% power and maintain the temperature for 60 minutes; Phase 3: Maintain target temperature at 100% power.

8. The silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace according to claim 1 is characterized in that: The silicon dioxide purity of the quartz sand in step 5 is greater than or equal to 98%.

9. The silicon carbide smelting process based on spent material charging in a closed negative pressure down-jump smelting furnace according to claim 1 is characterized in that: The leap-type smelting furnace is a fully sealed structure, and a circulating cooling water channel is built into the furnace wall.

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