Low-carbon smelting process and system of industrial silicon submerged arc furnace

Abstract

The invention discloses a low-carbon smelting system of an industrial silicon submerged arc furnace. The low-carbon smelting system comprises a first conveying unit, a selection unit, a component detection unit, a second conveying unit, a first preheating unit, a third conveying unit and a plurality of second preheating units. The fine selection unit is used for feeding through the first conveying unit, fine selection raw materials of the fine selection unit are conveyed to the first preheating unit through the second conveying unit, and the raw materials preheated by the first preheating unit are conveyed into the second preheating unit through the third conveying unit for secondary preheating and then conveyed into the industrial silicon furnace; the invention further discloses a low-carbon smelting process of the industrial silicon submerged arc furnace. Raw material screening and accurate raw material proportioning are adopted, the quality of the materials is guaranteed from the source, the raw materials are preheated and dried through pouring waste heat before entering the furnace, larger-amplitude heating is conducted before entering the furnace, the state and quality of the raw materials after entering the furnace are guaranteed, then continuous feeding is conducted according to the material surface in the furnace, and stable and uniform feeding is conducted; and the power factor of the electrode is ensured, so that the purpose of low-carbon production is achieved.

Description

Technical Field

[0001] This invention relates to the field of industrial silicon production technology, and in particular to a low-carbon smelting process and system for an industrial silicon submerged arc furnace. Background Technology

[0002] Industrial silicon is an indispensable basic raw material for many modern industries. Its core value lies in its extremely high chemical purity silicon content (typically 98%-99.5%). Through different downstream processing paths, it has given rise to material systems supporting multiple key industries. It can be used as an alloying additive to improve mechanical properties and casting performance; it can also be used as a core starting material for synthesizing organosilicon monomers. Organosilicon materials combine the high and low temperature resistance and aging resistance of inorganic materials with the flexibility of organic materials, making them extremely widely used. Its strategic value lies in the application of solar-grade polycrystalline silicon and electronic-grade polycrystalline silicon, which have extremely high added value.

[0003] Industrial silicon production is a typical energy-intensive industry, requiring approximately 11,000-13,000 kWh of electricity to produce one ton of industrial silicon. The smelting process generates smoke and waste gas, necessitating the use of efficient dust removal and flue gas purification systems. Therefore, reducing energy consumption and utilizing waste heat have always been key development directions for production enterprises. Since furnace design is relatively mature and cannot be easily changed, conventional development can only focus on the upstream production grading system. In industrial silicon production, the main factor is the stable operation of the electrodes, with a focus on optimizing core parameters such as electrode position, current and voltage, furnace charge ratio, and feeding speed. Optimizing and ensuring precise system control plays a crucial role in low-carbon smelting. To address these issues, we propose a low-carbon smelting process and system for an industrial silicon submerged arc furnace. Summary of the Invention

[0004] This application provides a low-carbon smelting process and system for an industrial silicon submerged arc furnace, which solves the problem of ensuring that the raw materials have a positive impact on the electrodes during the smelting process in industrial silicon production, and reducing the problem of raw material issues that reduce the electrode power factor.

[0005] This application provides a low-carbon smelting system for an industrial silicon submerged arc furnace, including a first conveying unit, a refining unit, a component detection unit, a second conveying unit, a first preheating unit, a third conveying unit, and multiple second preheating units; The selection unit is fed through the first conveying unit, and the selected raw materials of the selection unit are sent to the first preheating unit through the second conveying unit. The raw materials preheated by the first preheating unit are sent to the second preheating unit through the third conveying unit for secondary preheating before being sent to the industrial silicon furnace. The first preheating unit includes a heating chamber, with hot gas connecting pipes at both ends of the heating chamber. The hot gas connecting pipes are connected to the casting flue gas system of the industrial silicon furnace. A preheating barrel is installed through the heating chamber. The second conveying unit corresponds to the preheating barrel. A guide plate is installed inside the preheating barrel. A dust removal chamber is installed at the bottom of the heating chamber. The second preheating unit includes a preheating tube extending into the industrial silicon furnace, a thermocouple being installed inside the preheating tube, and a feeding assembly being installed at one end of the preheating tube located inside the industrial silicon furnace.

[0006] Preferably, the selection unit includes a screening box, in which a screening cage is inclinedly arranged. The raw material from the first conveying unit is fed into the screening cage through a feeding hopper. A collection hopper corresponding to the second conveying unit is provided at the bottom of the screening box, and a discharge hopper for discharging non-conforming materials is provided at the tail of the screening box.

[0007] Preferably, the second conveying unit includes a feeding conveyor belt disposed below the collecting hopper. The raw materials on the feeding conveyor belt are conveyed to the feeding belt via a weighing conveyor belt. The raw materials on the feeding belt are conveyed to the first preheating unit via a bucket elevator. The component detection unit is located on the feeding conveyor belt. The feeding conveyor belt includes a bracket fixed on the feeding conveyor belt and a neutron detector mounted on the bracket.

[0008] Preferably, the third conveying unit includes a collection box for collecting the raw materials of the preheating barrel. The raw materials in the collection box are connected to a temporary storage hopper via a conveying auger. A rotary distributor is provided at the bottom of the temporary storage hopper. The rotary distributor is connected to the second preheating unit via a discharge pipe.

[0009] Preferably, the feeding pipe is connected to the preheating pipe via a buffer hopper.

[0010] Preferably, the feeding assembly includes a sealing gate at one end of the preheating pipe, and multiple connecting posts are fixed on one side of the preheating pipe. The multiple connecting posts extend into the preheating pipe, and a limit ring is installed on the multiple connecting posts. A connecting rod is installed on the limit ring and extends out of the preheating pipe. The connecting rod is connected to a cylinder installed on the outside. A limit block is provided inside the preheating pipe to prevent the limit ring from falling off.

[0011] Preferably, the ash removal chamber includes an ash storage hopper disposed at the bottom of the heating chamber, and the ash storage hopper is provided with a discharge valve.

[0012] Preferably, there are ten second preheating units.

[0013] This application, based on the aforementioned low-carbon smelting system of an industrial silicon submerged arc furnace, further includes a low-carbon smelting process for the industrial silicon submerged arc furnace, comprising the following steps: S1, Material preparation: Wash the qualified silica fragments with water, dry them in the drying shed, and send the silica and carbonaceous reducing agent to the batching warehouse. S2, silica and carbonaceous reducing agent are delivered to the first conveying unit through the plant distribution system, and then refined in the refining unit; S3, the selected silica and carbonaceous reducing agent are sent to the first preheating unit and preheated to 100-150℃; S4, the preheated silica and carbonaceous reducing agent are sent to multiple second preheating units through the third conveying unit for preheating before being unloaded; S5, based on the material level deficiency around the three-phase electrodes in the furnace, controls the feeding of the corresponding second preheating unit to replenish the material level.

[0014] Preferably, the material level is located 300-400mm above the furnace shell.

[0015] As can be seen from the above technical solutions, this application provides a low-carbon smelting process and system for an industrial silicon submerged arc furnace. This application achieves optimal process coordination and low-carbon smelting by jointly controlling the feed and material level. Specifically, in the initial stage, the raw materials are selected in a fine-graining unit. Qualified silica and carbonaceous reducing agent are then batched in a certain proportion in a second conveying unit. After batching, the mixture is sent to the first preheating unit where the silica and carbonaceous reducing agent mixture is preheated using cast flue gas. This process is both a preheating process and a deep treatment process before entering the furnace, heating the initial temperature of the raw materials to 100-150℃. This process removes all moisture from the raw materials, significantly reducing their water content. The flue gas generated during this process is treated by a casting flue gas system. The dehydrated raw materials are then sent to the second preheating unit via the third conveying unit. A portion of the second preheating unit extends into the furnace body, utilizing the temperature inside the furnace to preheat the raw materials to be fed in a secondary process. During this preheating process, the raw materials are preheated to 400-600℃. This process requires the same isolation measures as the furnace body to prevent the oxidation of the carbonaceous reducing agent. Then, based on the collapse at the electrodes inside the furnace, materials are replenished in real time to ensure that the material surface is always at the optimal height of 300-400mm above the furnace shell.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. By setting up the selection unit, the quality of the raw materials before entering the furnace is guaranteed, ensuring that the composition and particle size are within the required range, which can guarantee the resistance of the raw materials after entering the furnace and guarantee the electrode power factor. 2. By setting up the first preheating unit, the flue gas generated during casting is recovered and the raw materials are preheated. This removes the residual moisture in the raw materials, significantly reduces the moisture content of the raw materials, and thus reduces energy consumption in smelting. 3. By setting up the third preheating unit, the heat inside the furnace is used to significantly raise the temperature of the raw materials before they are put into the furnace. After they are put into the furnace, they are quickly heated to the furnace temperature, further reducing power consumption and achieving the goal of low-carbon production.

[0017] In summary, this application employs high-quality raw material screening and precise raw material ratios to ensure material quality at the source. Before entering the furnace, the raw materials are preheated and dried using residual heat from casting, and then heated even more significantly before entering the furnace to ensure the state and quality of the raw materials after entering the furnace. Subsequently, continuous, stable, and uniform feeding is carried out according to the material level in the furnace to ensure the power factor of the electrodes, thereby achieving the goal of low-carbon production. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the implementation examples will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a low-carbon smelting system for an industrial silicon submerged arc furnace proposed in this invention. Figure 2 This is a second-view structural schematic diagram of a low-carbon smelting system for an industrial silicon submerged arc furnace proposed in this invention. Figure 3 This is a schematic diagram of a selected unit structure of a low-carbon smelting system for an industrial silicon submerged arc furnace proposed in this invention. Figure 4 This is a schematic diagram of the first preheating unit structure of a low-carbon smelting system for an industrial silicon submerged arc furnace proposed in this invention. Figure 5 This is a schematic diagram of the second preheating unit structure of a low-carbon smelting system for an industrial silicon submerged arc furnace proposed in this invention. Figure 6 This is a schematic diagram of the feeding component structure of a low-carbon smelting system for an industrial silicon submerged arc furnace proposed in this invention. Figure 7 This is a schematic diagram of the thermocouple installation structure of a low-carbon smelting system for an industrial silicon submerged arc furnace proposed in this invention. Figure 8 This is a schematic diagram of the limit block installation structure of a low-carbon smelting system for an industrial silicon submerged arc furnace proposed in this invention. Figure 9 This is a table showing the monthly production unit consumption data for a low-carbon smelting process using an industrial silicon submerged arc furnace proposed in this invention.

[0020] In the diagram: 1 First conveying unit, 2 Fine selection unit, 21 Feeding hopper, 22 Screening box, 23 Screening cage, 24 Collection hopper, 25 Discharge hopper, 3 Component detection unit, 31 Support, 32 Neutron detector, 4 Second conveying unit, 41 Discharge conveyor belt, 42 Weighing conveyor belt, 43 Feeding belt, 44 Bucket elevator, 45 Feed hopper, 5 First preheating unit, 51 Preheating barrel, 511 Guide plate, 52 Heating chamber, 53 Ash storage hopper, 54 Discharge valve, 55 Hot air connection pipe, 6 Third conveying unit, 61 Collection box, 62 Conveying auger, 63 Temporary storage hopper, 64 Rotary distributor, 65 Discharge pipe, 7 Second preheating unit, 71 Buffer hopper, 72 Discharge assembly, 721 Cylinder, 722 Connecting rod, 723 Limiting ring, 724 Connecting column, 725 Sealing door, 73 Preheating pipe, 731 Limiting block, 8 Thermocouple. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0022] See Figure 1-8 This application discloses a low-carbon smelting system for an industrial silicon submerged arc furnace. By controlling the raw materials, the combination, and the feeding temperature, the system achieves the goal of low-carbon production. Specifically, it includes a first conveying unit 1, a fine selection unit 2, a component detection unit 3, a second conveying unit 4, a first preheating unit 5, a third conveying unit 6, and multiple second preheating units 7 to complete the raw material distribution in industrial silicon production, thereby ensuring production. Specifically, this application has ten second preheating units 7, which are evenly distributed on the industrial silicon furnace for uniform feeding of the industrial silicon furnace. The selection unit 2 is fed through the first conveying unit 1. The first conveying unit 1 of this application can be a belt conveyor, bucket elevator, scraper conveyor, etc., as long as it can stably provide material transportation. The attached figure of this application shows the bucket elevator of the original factory area, which is not specifically limited here. The selected raw materials of the selection unit 2 are sent to the first preheating unit 5 through the second conveying unit 4. After selection, the raw materials are batched in a certain proportion through the second conveying unit 4. The specific batching ratio is determined in the laboratory according to the specific situation of silica and carbonaceous reducing agent. The specific ratio is not an innovation of this application and will not be described in detail here. The raw materials are batched and conveyed on the second conveying unit 4 and sent to the first preheating unit 5. The raw materials preheated in the first preheating unit 5 are sent to the second preheating unit 7 through the third conveying unit 6 for secondary preheating and then sent to the industrial silicon furnace. After the raw materials are batched, they are fed according to the furnace conditions after two preheatings. The purposes of the first preheating and the second preheating are different, as detailed below. The first preheating unit 5 includes a heating chamber 52, which is a closed chamber with insulation material on the outside and refractory material on the inside. The chamber is used to introduce flue gas with relatively low temperatures during the production stage. Specifically, hot gas connecting pipes 55 are installed at both ends of the heating chamber 52, one for inlet and one for outlet, ensuring temperature stability within the heating chamber 52. The hot gas connecting pipes 55 are connected to the casting flue gas system of the industrial silicon furnace. In addition to utilizing casting flue gas, the hot gas connecting pipes 55 of this application can also utilize flue gas from the waste heat recovery system that has entered the dust removal system, allowing it to enter this application first. After entering the dust removal system, the setup of this application will not affect the original waste heat recovery in the original system, that is, it will not affect the original waste heat recovery revenue. A preheating barrel 51 is installed through the heating chamber 52. The preheating barrel 51 is heated in the heating chamber 52. The raw material is preheated for the first time in the preheating barrel 51. This application divides the preheating process into two stages, which has three aspects of significance. First, it utilizes the relatively low calorific value after preheating and casting, but with a large amount of waste heat, for secondary utilization. Second, it utilizes this preheating process because the moisture content in the raw material is difficult to determine, especially for silica, to ensure its quality after entering the plant. The quantity will be washed with water to remove mud and sand. Although it is dried in the drying chamber, it still contains some moisture. It can dry the raw materials. Thirdly, the flue gas after the first preheating will enter the dust removal system for treatment. This application can directly use the dust removal system to directly recover and reuse the flue gas generated during the drying process. It is set up in the system, which can save pipeline and layout costs. The flue gas treatment system of the preheating barrel 51 is not marked in this application. Specifically, a dust collection hood from the dust removal system can be placed over the feed inlet of the preheating barrel 51. The second conveying unit 4 corresponds to the preheating barrel 51. The second conveying unit 4 will transport the raw materials. The material is fed into the preheating barrel 51, which is equipped with a guide plate 511. The preheating barrel 51 is placed horizontally. The conveying speed of the material is adjusted by the guide plate 511 and the rotation speed of the preheating barrel 51, thereby controlling the residence time in the preheating barrel 51 and achieving the purpose of temperature control. Furthermore, a dust removal chamber is provided at the bottom of the heating chamber 52. Since there is still some dust in the flue gas, it settles in the dust removal chamber at the bottom and is cleaned regularly. The dust removal chamber includes an ash hopper 53 at the bottom of the heating chamber 52. A discharge valve 54 is provided on the ash hopper 53. The discharge valve 54 is opened regularly to discharge ash. The second preheating unit 7 includes a preheating tube 73 extending into the industrial silicon furnace. The preheating tube 73 is made of refractory material, specifically silicon carbide refractory tube or metal-ceramic composite tube. Since raw materials are continuously added into the preheating tube 73, its temperature only needs to withstand a high temperature of 1000℃. A thermocouple 8 is installed inside the preheating tube 73. The thermocouple 8 is a high-temperature resistant K-type thermocouple that extends along one end of the preheating tube 73 into the interior of the preheating tube 73 to detect the internal temperature and prevent it from becoming too high. It also detects the temperature of the raw materials. A feeding assembly 72 is installed at one end of the preheating tube 73 inside the industrial silicon furnace to control the opening and closing of the preheating tube 73 and control the feeding.

[0023] In this application, the selection unit 2 includes a screening box 22, which mainly collects raw materials that meet the particle size requirements and performs screening. Specifically, a screening cage 23 is inclinedly arranged inside the screening box 22. The aperture of the screening cage 23 is 20cm, which is used to screen carbonaceous reducing agent and silica with a particle size of less than 20mm. In this application, the carbonaceous reducing agent and silica use the same particle size configuration to ensure the overall resistance inside the furnace and facilitate deep electrode insertion. The raw materials from the first conveying unit 1 are sent to the screening cage 23 through the feeding hopper 21. The bottom of the screening box 22 is provided with a collection hopper 24 corresponding to the second conveying unit 4. The second conveying unit 4 is 10-15cm away from the collection hopper 24. The raw materials in the collection hopper 24 accumulate on the conveyor belt. The discharge amount of the raw materials is controlled by adjusting the speed of the conveyor belt. The tail of the screening box 22 is provided with a discharge hopper 25 for discharging non-compliant materials. This part of the raw materials is sent to the warehouse for re-crushing via the discharge hopper 25 and the conveyor belt. In this application, the selection unit 2 can accurately control the particle size of the raw materials, thereby ensuring their performance after entering the furnace.

[0024] In this application, the second conveying unit 4 includes a feeding conveyor belt 41 disposed below the collection hopper 24. The feeding conveyor belt 41 is controlled by a variable frequency motor. The feeding amount is controlled by controlling the speed of the feeding conveyor belt 41. Specifically, the raw materials on the feeding conveyor belt 41 are sent to the feeding belt 43 via the weighing conveyor belt 42. The weighing conveyor belt 42 achieves stable and controllable raw material conveying, and then the raw materials are sent out by the feeding belt 43. Further, the raw materials on the feeding belt 43 are sent to the first preheating unit 5 via the bucket elevator 44. When the vertical drop of the first preheating unit 5 is large, the bucket elevator 44 can be used to deliver the raw materials. A feeding hopper is provided at the junction of the feeding belt 43 and the bucket elevator 44 to avoid spillage during conveying. Since the mixing process has not yet been carried out, spillage is often caused by a single raw material. Therefore, spillage will affect the mixing ratio, so protective measures are required at this point. Furthermore, the component detection unit 3 is located on the feeding conveyor belt 41. The feeding conveyor belt 41 includes a bracket 31 fixed on the feeding conveyor belt 41 and a neutron detector 32 installed on the bracket 31. The neutron detector 32 can analyze the specific components more specifically. When an abnormality in the components occurs, the machine can be stopped and an alarm can be set off, or the raw material segment can be controlled to fall onto the weighing conveyor belt 42. The weighing conveyor belt 42 will then start in reverse to discharge the raw material segment.

[0025] In this application, the third conveying unit 6 includes a collection box 61 for collecting raw materials from the preheating barrel 51. The collection box 61 collects the raw materials that have been preheated for the first time from the preheating barrel 51 to prevent them from scattering. During preheating, the raw materials are also mixed. Since the raw materials have a certain initial temperature, the raw materials in the collection box 61 are connected to a temporary storage hopper 63 via a conveying auger 62 and conveyed by the auger 62. The connection between the auger and the motor is cooled by circulating water, so there is no impact. A rotary distributor is installed at the bottom of the temporary storage hopper 63. 64. The rotary distributor 64 is used to distribute raw materials to each of the lower second preheating units 7. Specifically, the rotary distributor 64 is connected to the second preheating unit 7 through the feed pipe 65. In this application, the feed pipe 65 is connected to the preheating pipe 73 through the buffer hopper 71. This setting is used to adjust the angle of the preheating pipe 73 so that the axis of the preheating pipe 73 is deflected by a certain angle with the axis of the buffer hopper 71, thereby facilitating the installation of other components inside the preheating pipe 73. At the same time, it also creates an angle for the preheating pipe 73 located in the furnace, increasing the distance from the bottom.

[0026] In this application, the unloading assembly 72 includes a sealing gate 725 disposed at one end of the preheating tube 73. The sealing gate 725 is made of the same material as the preheating tube 73. The sealing gate 725 is used to block the tail end of the preheating tube 73. Multiple connecting posts 724 are fixed to one side of the sealing gate 725 on the preheating tube 73. All connecting posts 724 extend into the preheating tube 73, and a limiting ring 723 is commonly installed on each of the multiple connecting posts 724. The connecting posts 724 slide within the preheating tube 73 via the limiting ring 723, thereby limiting the movement of the sealing gate 725. The sliding limit ring 723 controls the opening and closing of the sealing door 725 to achieve the purpose of opening and closing for material feeding. Furthermore, a connecting rod 722 is installed on the limit ring 723. The connecting rod 722 extends to the outside of the preheating tube 73 and is connected to a cylinder 721 installed on the outside. The position of the connecting rod 722 is controlled by the cylinder 721 to control the sealing door 725. In addition, a limit block 731 is provided inside the preheating tube 73 to prevent the limit ring 723 from falling off, so as to prevent the above structure from falling into the furnace after the connection breaks, thus achieving the purpose of protection.

[0027] This application also includes a low-carbon smelting process for an industrial silicon submerged arc furnace based on a low-carbon smelting system, comprising the following steps: S1, Material preparation: The qualified silica fragments are washed with water to remove surface dirt and fine powder, improving the quality of the raw materials entering the furnace. The raw materials are dried in the drying shed. Specifically, raw materials that are not used for a short period of time need to be stored and dried in the drying shed after cleaning. If they are not used for a short period of time, they can be dried by air drying. Silica and carbonaceous reducing agent are sent to the batching warehouse. In the batching warehouse, a high-rise conveyor belt is used to stack and transport the materials. S2, silica and carbonaceous reducing agent are delivered to the first conveying unit 1 through the plant distribution system. Specifically, each batching warehouse is equipped with two 5t grab loader trucks, which deliver the raw materials to the first conveying unit 1 via conveyor belt. The raw materials are then selected by the selection unit 2 to ensure the control of the particle size of the raw materials and to guarantee the quality of the furnace. S3, the selected silica and carbonaceous reducing agent are sent to the first preheating unit 5, and the waste heat entering the dust removal unit at the end is used for heating. This allows the waste heat at the very end of the production system to be reused, thereby reducing the total power consumption in the production system. Since the heat at this stage is around 200°C, the raw materials are preheated to 100-150°C at this stage for dehydration and initial preheating. S4, the preheated silica and carbonaceous reducing agent are sent to multiple second preheating units 7 through the third conveying unit 6. The multiple second preheating units 7 are distributed on the industrial silicon furnace. The materials are fed evenly. The whole process is continuous production with batch feeding and intermittent silicon discharge. The raw materials entering the second preheating unit 7 are preheated and waiting to be fed. During this stage, they can be heated to 400-600℃. After feeding, they can be quickly heated to the furnace temperature, thereby reducing power consumption. They are quickly heated, melted, and undergo a reduction reaction. During the smelting process, the resistance and permeability of the furnace charge can be guaranteed. S5, the specific feeding is determined by the thickness of the furnace charge. The feeding is controlled based on the level of the charge around the three-phase electrodes inside the furnace. In this application, the charge level is 300-400mm above the furnace shell. When it falls below this setting, the corresponding second preheating unit 7 is promptly controlled to replenish the charge level, ensuring proper charge level maintenance, reducing "sparking" on the charge level, guaranteeing electrode depth, expanding the high-temperature zone, improving reduction efficiency, and reducing heat loss from the upper charge layer and fugitive CO emissions. This application has minimal impact on the original system and does not affect the recovery of waste heat recovery systems within the original system. It represents a further utilization of waste heat on top of the original system, improving carbon reduction efficiency. Figure 9 As shown, energy consumption is reduced by about 3% compared to the original system. With further refinement of production, it is expected that the power consumption per ton can be reduced to less than 10,000 kWh.

[0028] As can be seen from the above technical solution, this application achieves optimal process coordination and low-carbon smelting by jointly controlling the feed and material level. Specifically, in the initial stage, the raw materials are selected in the fine-selection unit 2. Silica and carbonaceous reducing agent of qualified particle size are then mixed in a certain proportion in the second conveying unit 4. After mixing, the mixture is sent to the first preheating unit 5, where the silica and carbonaceous reducing agent mixture is preheated by the flue gas. This process is both a preheating process and a deep treatment process before entering the furnace. This process heats the initial temperature of the raw materials to 100-150℃, and can remove water from the raw materials during this process. The moisture content of the raw material is significantly reduced by removing all impurities. The flue gas generated during this process is treated by a casting flue gas system. The dehydrated raw material is then sent to the second preheating unit 7 via the third conveying unit 6. A portion of the second preheating unit 7 extends into the furnace body, where the temperature inside the furnace body is used to preheat the raw material to be fed in a second stage. During this preheating process, the raw material is preheated to 400-600°C. This process requires the same isolation method as the furnace body to prevent oxidation of the carbonaceous reducing agent. Then, based on the collapse of the electrodes inside the furnace, the material is replenished in real time to ensure that the material surface is always at the optimal height of 300-400mm above the furnace shell.

[0029] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope of this application is indicated by the claims.

[0030] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The embodiments of this application described above do not constitute a limitation on the scope of protection of this application.

Claims

1. A low-carbon smelting system for an industrial silicon submerged arc furnace, comprising a first conveying unit (1), a fine selection unit (2), a composition detection unit (3), a second conveying unit (4), a first preheating unit (5), a third conveying unit (6), and multiple second preheating units (7). Its features are: The selection unit (2) is fed through the first conveying unit (1), and the selected raw materials of the selection unit (2) are sent to the first preheating unit (5) through the second conveying unit (4). The raw materials preheated by the first preheating unit (5) are sent to the second preheating unit (7) through the third conveying unit (6) for secondary preheating and then sent to the industrial silicon furnace. The first preheating unit (5) includes a heating chamber (52), and hot gas connecting pipes (55) are provided at both ends of the heating chamber (52). The hot gas connecting pipes (55) are connected to the casting flue gas system of the industrial silicon furnace. A preheating barrel (51) is provided through the heating chamber (52). The second conveying unit (4) corresponds to the preheating barrel (51). A guide plate (511) is provided inside the preheating barrel (51). A dust removal chamber is provided at the bottom of the heating chamber (52). The second preheating unit (7) includes a preheating tube (73) extending into the industrial silicon furnace. A thermocouple (8) is installed inside the preheating tube (73). A feeding assembly (72) is installed at one end of the preheating tube (73) located inside the industrial silicon furnace.

2. The low-carbon smelting system of an industrial silicon submerged arc furnace according to claim 1, characterized in that, The selection unit (2) includes a screening box (22), and a screening cage (23) is inclinedly arranged inside the screening box (22). The raw material of the first conveying unit (1) is sent to the screening cage (23) through the feeding hopper (21). The bottom of the screening box (22) is provided with a collection hopper (24) corresponding to the second conveying unit (4). The tail of the screening box (22) is provided with a discharge hopper (25) for discharging non-compliant materials.

3. The low-carbon smelting system of an industrial silicon submerged arc furnace according to claim 2, characterized in that, The second conveying unit (4) includes a feeding conveyor belt (41) disposed below the collection hopper (24). The raw materials on the feeding conveyor belt (41) are sent to the feeding belt (43) via the weighing conveyor belt (42). The raw materials on the feeding belt (43) are sent to the first preheating unit (5) via the bucket elevator (44). The component detection unit (3) is located on the feeding conveyor belt (41). The feeding conveyor belt (41) includes a bracket (31) fixed on the feeding conveyor belt (41) and a neutron detector (32) installed on the bracket (31).

4. The low-carbon smelting system of an industrial silicon submerged arc furnace according to claim 1, characterized in that, The third conveying unit (6) includes a collection box (61) for collecting the raw materials of the preheating barrel (51). The raw materials in the collection box (61) are connected to a temporary storage hopper (63) via a conveying auger (62). A rotary distributor (64) is provided at the bottom of the temporary storage hopper (63). The rotary distributor (64) is connected to the second preheating unit (7) via a discharge pipe (65).

5. A low-carbon smelting system for an industrial silicon submerged arc furnace according to claim 4, characterized in that, The feeding pipe (65) is connected to the preheating pipe (73) through the buffer hopper (71).

6. The low-carbon smelting system of an industrial silicon submerged arc furnace according to claim 1, characterized in that, The feeding assembly (72) includes a sealing gate (725) at one end of the preheating pipe (73). The sealing gate (725) is fixed with multiple connecting posts (724) on one side of the preheating pipe (73). The multiple connecting posts (724) extend into the preheating pipe (73). A limit ring (723) is installed on the multiple connecting posts (724). A connecting rod (722) is installed on the limit ring (723). The connecting rod (722) extends outside the preheating pipe (73) and is connected to a cylinder (721) installed on the outside. A limit block (731) is provided inside the preheating pipe (73) to prevent the limit ring (723) from falling off.

7. The low-carbon smelting system of an industrial silicon submerged arc furnace according to claim 1, characterized in that, The ash removal chamber includes an ash hopper (53) located at the bottom of the heating chamber (52), and a discharge valve (54) is provided on the ash hopper (53).

8. A low-carbon smelting system for an industrial silicon submerged arc furnace according to claim 1, characterized in that, The second preheating unit (7) consists of ten units.

9. A low-carbon smelting system based on the industrial silicon submerged arc furnace described in claims 1-8, further comprising a low-carbon smelting process for the industrial silicon submerged arc furnace, characterized in that, Includes the following steps: S1, Material preparation: Wash the qualified silica fragments with water, dry them in the drying shed, and send the silica and carbonaceous reducing agent to the batching warehouse. S2, silica and carbonaceous reducing agent are delivered to the first conveying unit (1) through the plant distribution system, and then refined by the refining unit (2); S3, the selected silica and carbonaceous reducing agent are sent to the first preheating unit (5) and preheated to 100-150℃; S4, the preheated silica and carbonaceous reducing agent are sent to multiple second preheating units (7) through the third conveying unit (6) for preheating before being unloaded; S5, based on the material level deficiency around the three-phase electrodes in the furnace, control the corresponding second preheating unit (7) to feed material to replenish the material level.

10. The low-carbon smelting process of the industrial silicon submerged arc furnace according to claim 9, characterized in that, The material level is located 300-400mm above the furnace shell.

Images