Device and method for preparing silicon monoxide

Abstract

The invention discloses a device and method for preparing silicon monoxide. The device for preparing silicon monoxide comprises a smelting storage system, a raw material adding system, an electromagnetic heating system and a collecting system, and the smelting storage system is provided with a storage cavity used for containing materials; the raw material adding system is provided with a plurality of material collecting bins communicating with the discharging cavity and used for adding raw materials into the material storage cavity. The electromagnetic heating system is arranged on the outer side of the smelting storage system and used for heating materials in the storage cavity. The collecting system is internally provided with a condensation vacuum chamber communicated with the material storage cavity, and the condensation vacuum chamber is used for absorbing volatile products in the material storage cavity and desublimating and collecting the volatile products; according to the invention, the silicon monoxide can be prepared by solid-liquid reaction, continuous feeding and quick change of the collecting barrel without destroying the vacuum condition, so that the production efficiency of the silicon monoxide is improved, the limitation of the original solid-solid reaction on the granularity and mixing uniformity of the raw materials is eliminated, and the preparation cost of the silicon monoxide is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of pyrometallurgy, and in particular to a device and method for preparing silicon oxide. Background Art

[0002] Developing high-energy-density energy storage technology is an important way to promote the widespread application of intermittent and regional clean renewable energy such as solar energy and wind energy. At the same time, the rapid development and popularization of new energy vehicles also require a large number of high-energy-density and high-safety energy storage devices. Lithium-ion batteries have the characteristics of long cycle life, high energy density, low self-discharge rate and wide operating temperature range, and have been widely used in electronic products, electric vehicles, aerospace and other fields. At present, the negative electrode material of traditional commercial lithium-ion batteries is mostly graphite. Although it has the advantages of high conductivity, good stability and low price, its theoretical specific capacity is only 372mAh.g-1, and its rate performance is poor, which is difficult to meet the requirements of high-energy-density batteries. Si-based materials have the advantages of high theoretical specific capacity, suitable operating voltage and abundant reserves, and have gradually attracted attention in recent years. Among them, SiO has the ability to reversibly insert / extract lithium, and its theoretical specific capacity is as high as 2400mAh.g-1. Its volume expansion rate, rate characteristics and cycle performance are better than those of Si. At the same time, its cost is much lower than that of silicon-carbon materials. Therefore, it is an ideal negative electrode material for lithium-ion batteries in the foreseeable medium and long term.

[0003] At present, the preparation principle of silicon oxide is Si+SiO2→SiO↑, that is, fine silicon powder and silicon dioxide powder are mixed in a 1:1 molar ratio, and then heated to 1300-1400℃ by resistance under vacuum conditions to carry out solid-solid reaction in a corundum tube and collect it by condensation. For example, the Chinese patent with publication number CN216712224U provides a device for preparing silicon oxide by evaporation, which mainly includes: a cavity, an inner furnace and a graphite barrel, a cavity arranged on the outside of the equipment; a graphite rod fixing hammer is used inside the cavity to suspend and fix the inner furnace in the cavity; and a graphite barrel is arranged in the furnace. The evaporation is carried out under vacuum to improve its production efficiency; at the same time, a graphite barrel is used. Since the graphite heating element of the graphite barrel is surface heating, it can generate more uniform heat, making the temperature transition in the graphite box more uniform. It is conducive to the high-purity condensation of silicon oxide and improves production efficiency.

[0004] However, the existing silicon oxide preparation generally adopts resistance heating, which has a slow heating rate and leads to low product productivity. Secondly, due to the solid-solid reaction (i.e. the reaction between fine silicon powder and silicon dioxide powder), the reaction speed is slow, and the raw material particle size (a particle size that is too small is easy to be sucked away during the vacuum process, and a particle size that is too large will further reduce the solid-solid reaction rate, generally 300-400 mesh) and mixing uniformity are required to be high. Obviously, the current traditional production method has low productivity and high production cost. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies, to provide a device and method for preparing silicon monoxide, and to solve the technical problems of low productivity and high production cost in the prior art of preparing silicon monoxide.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: In the first aspect, the present invention provides a device for preparing silicon iodine, comprising: a smelting storage system, a raw material feeding system, an electromagnetic heating system and a collecting system, wherein the smelting storage system has a storage cavity for containing materials; the raw material feeding system has a plurality of collecting bins connected to a discharge cavity for feeding raw materials into the storage cavity; the electromagnetic heating system is arranged on the outside of the smelting storage system for heating the material inside the storage cavity; the collecting system has a condensation vacuum chamber connected to the storage cavity, and the condensation vacuum chamber is used to absorb volatile products of the storage cavity and collect the volatile products by condensation.

[0007] In some embodiments, the smelting material storage system includes a furnace body, a crucible and a heat preservation layer, wherein the crucible is arranged inside the furnace body and is used to contain the melt; and the heat preservation layer covers the outside of the crucible. An observation window and a vacuum gauge are arranged on the furnace body, wherein the observation channel of the observation window extends to the inside of the crucible and is connected to the inside of the crucible, and the monitoring end of the vacuum gauge is arranged inside the furnace body and is used to measure the vacuum degree inside the furnace body.

[0008] In some embodiments, the silo of the raw material adding system includes a silica raw material silo and a silicon silo, and the silica raw material silo and the silicon silo are used to hold silica raw material and silicon raw material, respectively; the raw material adding system also includes a first unloading pipe, a second unloading pipe, a first unloading valve, and a second unloading valve. The silica raw material silo is connected to the interior of the storage cavity through the first unloading pipe, and the first unloading pipe is equipped with a first unloading valve. The silicon silo is connected to the interior of the storage cavity through the second unloading valve, and the second unloading pipe is equipped with a second unloading valve.

[0009] In some embodiments, the electromagnetic heating system includes a medium frequency induction heating power supply, an induction coil and a graphite heater. The induction coil is arranged around the outside of the crucible and is connected to the output electrode of the medium frequency induction heating power supply to generate an alternating electromagnetic field required for heating the material; the graphite heater is located on the inner side of the induction coil and is used for the initial melting of the silicon material; the graphite heater adopts a slit structure so that the electromagnetic field can penetrate into the interior of the graphite heater, directly act on the silicon material after melting to heat it, and use the penetrated electromagnetic field to stir the silicon melt.

[0010] In some embodiments, the collection system includes a water-cooled collection barrel and a vacuum pump; the water-cooled collection barrel is connected to the storage chamber through an insulated pipe and is used for condensation collection of volatile products; the vacuum pump is connected to the water-cooled collection barrel through a vacuum tube, and is used to maintain the reaction vacuum and extract the reaction volatile products into the water-cooled collection barrel; a filter is provided in the vacuum tube.

[0011] In a second aspect, the present invention further provides a method for preparing silicon 2 oxide, comprising the device for preparing silicon 2 oxide as described in any one of the above, the method comprising: S1: Assemble the subsystems according to the corresponding assembly relationship, respectively load granular silicon material and silicon dioxide material into the two collecting bins of the raw material feeding system, and pre-place part of silicon material in the storage cavity of the smelting storage system; S2: Close the material port of the smelting storage system and start the vacuum pump to extract vacuum; S3: Turn on the electromagnetic heating system to heat the silicon material in the storage chamber; S4: After the silicon material in the storage chamber is completely melted, the silicon dioxide material is added to the storage chamber by using the raw material feeding system to achieve the reaction between the silicon melt and the solid silicon dioxide under vacuum; S5: Start the collection system to absorb the volatile products in the storage chamber and collect the condensation of the volatile products; S6: When the silicon melt in the crucible is consumed to a set amount, stop adding silicon dioxide, and add silicon material to the storage chamber. After the silicon material is melted, stop adding silicon material, and then continuously add silicon dioxide material again, and repeat this cycle.

[0012] In some embodiments, in step S1, the size of the granular silicon material is 2-20 mesh, and the size of the granular silicon dioxide is 40-100 mesh. In step S4, the silicon dioxide raw material is supplemented continuously or intermittently, and the steps of intermittent supplementation are: feed-stop-feed.

[0013] Compared with the prior art, the device and method for preparing silicon dioxide provided by the present invention, through the smelting storage system, raw material feeding system, electromagnetic heating system and collection system, the electromagnetic heating system adopts electromagnetic induction heating, the raw material feeding system can continuously feed raw materials into the storage cavity without destroying the vacuum state of the smelting storage system, the condensation vacuum chamber of the collection system can absorb the volatile gas products in the storage cavity, and collect the volatile products by condensation, so as to realize the quick replacement of the collection barrel without destroying the vacuum condition, and the raw material feeding system can be used to continuously feed raw materials to continuously produce and prepare silicon dioxide, so that the present scheme prepares silicon dioxide by solid-liquid reaction, continuous feeding and quick replacement of the collection barrel without destroying the vacuum condition, which is conducive to improving the production efficiency of silicon dioxide; By adopting solid-liquid reaction (i.e. reaction of silicon melt with relatively fine solid silicon dioxide raw material) to prepare silicon dioxide, the limitation of the original solid-solid reaction on the particle size and mixing uniformity of raw materials (silicon and silicon dioxide) is eliminated, and relatively coarse raw materials can be used without mixing, which is conducive to reducing the cost of silicon dioxide preparation; The device proposed in this scheme has a compact structure, is safe and reliable, and occupies a small area; the proposed method is highly operational and economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the overall structure of a device for preparing silicon monoxide provided in an embodiment of the present invention; Figure 2 It is a structural schematic diagram of a smelting and material storage system of a device for preparing silicon monoxide provided in an embodiment of the present invention; Figure 3 It is a flow chart of a method for preparing silicon monoxide provided in an embodiment of the present invention.

[0015] Description of reference numerals: 1. Smelting storage system; 11. Furnace body; 12. Crucible; 13. Furnace cover; 14. Crucible cover; 15. Insulation layer; 151. First asbestos layer; 152. Second asbestos layer; 153. Third asbestos layer; 16. Observation window; 17. Refractory bricks; 18. Insulating ceramics; 19. Vacuum gauge; 2. Raw material dosing system; 21. Silica raw material bin; 22. Silicon material bin; 23. First discharge valve; 24. Second discharge valve; 25. First discharge pipe; 26. Second discharge pipe; 27. Combined material pipe; 3. Thermal system; 31. Medium frequency induction heating power supply; 32. Induction coil; 33. Graphite heater; 34. Water cooling cable; 35. Insulation sleeve; 36. Coil flange; 4. Collection system; 41. Water-cooled collection barrel; 42. Vacuum pump; 43. Insulation pipe; 44. Vacuum tube; 45. Filter; 46. Flange; 47. Butterfly valve. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] In order to solve the technical problems of low productivity and high production cost in the preparation of silicon oxide, the present invention provides a device and method for preparing silicon oxide, which can prepare silicon oxide by solid-liquid reaction, continuous feeding and quick replacement of collecting barrels without destroying vacuum conditions, which is beneficial to improving the production efficiency of silicon oxide, and also eliminates the limitations of the original solid-solid reaction on the particle size and mixing uniformity of raw materials. Coarser raw materials can be used without mixing, which is beneficial to reducing the cost of silicon oxide preparation, so as to realize continuous, efficient and low-cost preparation of silicon oxide, and adapt to the rapid development of high energy density lithium-ion batteries.

[0018] It should be noted that the apparatus and method for preparing silicon oxide described in the present invention are used for but not limited to the preparation of silicon oxide, etc. For the convenience of explanation, in the present invention, only the apparatus and method for preparing silicon oxide are used in the preparation of silicon oxide as an example for explanation, and the principle of applying the apparatus and method for preparing silicon oxide to the preparation of other products is substantially the same as the principle applied to the preparation of silicon oxide, and they will not be described one by one here.

[0019] In the first aspect, the present application provides a device for preparing silicon dioxide, see Figure 1 , Figure 1 This is a structural schematic diagram of an apparatus and method for preparing silicon iodine in an embodiment of the present invention. The apparatus for preparing silicon iodine includes: a smelting storage system 1, a raw material feeding system 2, an electromagnetic heating system 3 and a collecting system 4. The smelting storage system 1 has a storage cavity for containing materials; the raw material feeding system 2 has a plurality of collecting bins connected to a discharge cavity for feeding raw materials into the storage cavity; the electromagnetic heating system 3 is arranged on the outside of the smelting storage system 1, and is used for heating the material inside the storage cavity; the collecting system 4 has a condensation vacuum chamber connected to the storage cavity, and the condensation vacuum chamber is used for absorbing volatile products of the storage cavity and collecting the volatile products by condensation.

[0020] In this scheme, the storage cavity of the smelting storage system 1 is used to hold materials, and the raw material feeding system 2 has a plurality of collecting bins, which are connected to the discharge cavity. Raw materials can be continuously fed into the storage cavity without destroying the vacuum state of the smelting storage system 1. The electromagnetic heating system 3 is used to heat the materials inside the storage cavity. After the silicon material in the storage cavity is completely melted, the raw material feeding system 2 can be used to replenish silicon dioxide material into the storage cavity to realize the reaction between silicon melt and solid silicon dioxide under vacuum. The condensation vacuum chamber of the collection system 4 can absorb the volatile gas products in the storage cavity and collect the volatile products by condensation. When all the reaction products in the storage cavity are volatilized and discharged, the raw material feeding system 2 can be used to continuously feed raw materials to continuously carry out the production and preparation of silicon dioxide.

[0021] In order to contain the raw materials, in the present embodiment, the smelting storage system 1 comprises a furnace body 11, a crucible 12 and an insulation layer 15, wherein the crucible 12 is arranged inside the furnace body 11, and a storage cavity for containing the melt is formed inside the crucible 12; specifically, the furnace body 11 and the crucible 12 are both open at the top, and the tops of the furnace body 11 and the crucible 12 are sealed with a furnace cover 13 and a crucible cover 14 respectively, and the furnace cover 13 and the crucible cover 14 are used to seal the furnace body 11 and the crucible 12 respectively, so that a sealed space is formed inside the furnace body 11 and the crucible 12, and the furnace body 11 is also used for assembling the above subsystems, so that it becomes a complete set of continuous, efficient and low-cost silicon dioxide preparation device.

[0022] In order to achieve heat insulation and heat preservation of the storage chamber, the insulation layer 15 is coated on the outside of the crucible 12. In order to further reduce heat loss, preferably, the insulation layer 15 is made of asbestos material, which includes a first asbestos layer 151, a second asbestos layer 152 and a third asbestos layer 153. The first asbestos layer 151 covers the top of the crucible cover 14, and the second asbestos layer 152 is coated on the outside and bottom of the crucible 12 to achieve heat preservation of the crucible 12 and reduce heat loss. A refractory brick 17 is also provided at the bottom of the inner cavity of the furnace body 11, and the refractory brick 17 is padded on the bottom of the crucible 12 wrapped with the insulation layer 15.

[0023] Preferably, the crucible 12 is a quartz crucible 12 or a corundum crucible 12 .

[0024] In order to observe the reaction in the furnace and perform infrared temperature measurement, an observation window 16 is provided on the furnace body 11. In fact, the observation window 16 is provided on the furnace cover 13. The observation channel of the observation window 16 extends through the crucible cover 14 to the inside of the crucible 12 and is connected to the inside of the crucible 12, so that the staff can observe the situation in the furnace through the observation window 16. In order to display the vacuum degree, a vacuum gauge 19 is also provided. The vacuum gauge 19 is installed on the furnace cover 13. The monitoring end of the vacuum gauge 19 is provided inside the furnace body 11 to measure the vacuum degree inside the furnace body 11.

[0025] In this embodiment, the raw material adding system 2 is provided with two silos, including a silica raw material silo 21 and a silicon silo 22, wherein the silica raw material silo 21 and the silicon silo 22 are respectively used to contain finer silica raw materials and coarser silicon raw materials; the raw material adding system 2 also includes a first unloading valve 23, a second unloading valve 24, a first unloading pipe 25, and a second unloading pipe 26, wherein the silica raw material silo 21 is connected to the interior of the storage cavity through the first unloading pipe 25, and the first unloading pipe 25 is provided with a first unloading valve 23, and the silicon silo 22 is connected to the interior of the storage cavity through the second unloading pipe 26, and the second unloading pipe 26 is provided with a second unloading valve 24. The first unloading pipe 25 is connected to the silica raw material bin 21 and the storage chamber, the second unloading pipe 26 is connected to the silicon material bin 22 and the storage chamber, the first unloading valve 23 and the second unloading valve 24 are respectively under the silica raw material bin 21 and the silicon material bin 22, and are respectively used to close or open the first unloading pipe 25 and the second unloading pipe 26. During implementation, the first unloading pipe 25 and the second unloading pipe 26 can be controlled by the unloading valve to replenish silica material and silicon material into the crucible 12.

[0026] Furthermore, in order to concentrate the added raw materials in the middle of the crucible 12, a combining pipe 27 is provided. The combining pipe 27 is arranged directly above the crucible 12, passes through the middle of the crucible cover 14 of the crucible 12 and is connected to the inside of the crucible 12. The top end of the combining pipe 27 is connected to the discharge ends of the first discharge pipe 25 and the second discharge pipe 26, so that the silica raw material bin 21 and the silicon material bin 22 can enter the combining pipe 27 through the first discharge pipe 25 and the second discharge pipe 26 respectively, and the materials are delivered into the crucible 12 through the combining pipe 27, and the added silica material or silicon material is concentrated in the middle of the molten pool of the crucible 12.

[0027] Preferably, the first discharge valve 23 and the second discharge valve 24 are both star-shaped discharge valves.

[0028] In order to achieve heating and stirring of the raw materials in the crucible 12, in this embodiment, the electromagnetic heating system 3 includes a medium frequency induction heating power supply 31, an induction coil 32 and a graphite heater 33. The induction coil 32 is wound around the outside of the crucible 12, between the crucible 12 and the insulation layer 15, and is connected to the output electrode of the medium frequency induction heating power supply 31 to generate an alternating electromagnetic field required for heating the material; the graphite heater 33 is located on the inner side of the induction coil 32, which is arranged on the side wall of the crucible 12, between the crucible 12 and the induction coil 32, and the graphite heater 33 is used for the initial melting of the silicon material; the graphite heater 33 adopts a slit structure so that the electromagnetic field penetrates into the graphite heater 33, directly acts on the silicon material after melting to heat it, and uses the penetrated electromagnetic field to stir the silicon melt.

[0029] Among them, the induction coil 32 is connected to the water-cooling cable 34 through the coil flange 36, and the water-cooling cable 34 is connected to the medium-frequency induction heating power supply 31; to prevent the furnace body 11 from being electrified, the water-cooling cable 34 and the furnace body 11 are isolated and insulated by an insulating sleeve 35; to prevent the heat of the slit graphite heater 33 from being carried away by the circulating cooling water in the induction coil 32, the graphite heater 33 and the induction coil 32 are separated by insulating ceramics 18.

[0030] During implementation, the medium frequency induction heating power supply 31 supplies power to the induction coil 32 and gradually increases the power, and heats the silicon material inside the crucible 12 through the induction coil 32 and the graphite heater 33, which is used for the initial melting of the silicon material and heating the silicon material after melting.

[0031] In order to realize the collection of reaction products, in this embodiment, the collection system 4 includes a water-cooled collection barrel 41 and a vacuum pump 42; the water-cooled collection barrel 41 is connected to the storage chamber through an insulation pipe 43, and is assembled on the furnace body 11 by a flange 46, for the condensation and collection of volatile products; the vacuum pump 42 is connected to the water-cooled collection barrel 41 through a vacuum pipe 44, for maintaining the reaction vacuum and extracting the reaction volatile products into the water-cooled collection barrel 41. During implementation, the vacuum pump 42 generates negative pressure inside the water-cooled collection barrel 41, extracts the reaction product (gaseous silicon dioxide) into the water-cooled collection barrel 41, and the cooling water of the water-cooled collection barrel 41 can cool the reaction product inside the water-cooled collection barrel 41, realizing the condensation and collection of the reaction product on the inner wall of the water-cooled collection barrel 41.

[0032] Preferably, the heat-insulating pipe 43 is a corundum tube, which is used as a collection channel for gaseous silicon oxide.

[0033] Furthermore, since the storage chamber in the crucible 12 is connected to the interior of the water-cooled collection barrel 41 through the insulation pipe 43, in order to prevent the insulation pipe 43 from dissipating heat and causing a large amount of gaseous silicon oxide to condense on its inner wall, the third asbestos layer 153 is coated on the outside of the insulation pipe 43 to prevent the volatile products from condensing in the insulation pipe 43 during transportation.

[0034] When the water-cooled collection barrel 41 is full of products and needs to be replaced, in order to achieve continuous production of silicon dioxide without destroying the vacuum in the furnace, a butterfly valve 47 is installed between the water-cooled collection barrel 41 and the furnace body 11, and the butterfly valve 47 is connected to the furnace body 11 through a flange 46, and is also connected to the water-cooled collection barrel 41 through the flange 46. Therefore, after the water-cooled collection barrel 41 is full of products, the butterfly valve 47 can be closed, and the water-cooled collection barrel 41 can be disassembled through the flange 46 between the butterfly valve 47 and the water-cooled collection barrel 41, and then replaced with a new water-cooled collection barrel 41. The vacuum state in the furnace will not be destroyed during the replacement process, and continuous production of silicon dioxide can be achieved.

[0035] After the gaseous silicon oxide is sucked into the water-cooled collection barrel 41, it is condensed into solid silicon oxide. In order to prevent the solid silicon oxide from being sucked into the vacuum pump 42, in this embodiment, a filter 45 is provided in the vacuum tube 44 to filter the solid silicon oxide. The filter 45 is installed at one end of the vacuum tube 44 close to the water-cooled collection barrel 41.

[0036] It should be noted that the water-cooled collection barrel 41 is a prior art, and its working principle mainly relies on the coordinated action of the motor, the pump body and the impeller. The motor provides power and is connected to the impeller in the pump body through a shaft. When the motor is started, the impeller begins to rotate. This rotational motion causes the water to flow, causing the pump body suction port to suck in cooling water, which is then transported to the water-cooled collection barrel 41 through the rotating impeller and then transported to the cooling equipment through a pipeline. The water absorbs heat in the water-cooled collection barrel 41 and becomes hot, thereby realizing the condensation and collection of the reaction products. It is then cooled in the cooling equipment and then returned to the water inlet of the water-cooled collection barrel 41 through a pipeline, completing the entire cycle.

[0037] In a second aspect, an embodiment of the present invention further provides a method for preparing silicon 2 oxide, comprising the device for preparing silicon 2 oxide provided by any one of the above embodiments, the method comprising: S1: Assemble the subsystems according to the corresponding assembly relationship, respectively load granular silicon material and silicon dioxide material into the two collecting bins of the raw material feeding system 2, and pre-place part of silicon material in the storage cavity of the smelting storage system 1.

[0038] Among them, the size of granular silicon material is 2-20 mesh, and the size of granular silicon dioxide is 40-100 mesh.

[0039] S2: closing the material port of the smelting material storage system 1 and starting the vacuum pump 42 to extract vacuum.

[0040] The vacuum pump 42 draws a vacuum degree of 10 -1 -10Pa.

[0041] S3: Turn on the electromagnetic heating system 3 to heat the silicon material in the material storage chamber.

[0042] S4: After the silicon material in the storage chamber is completely melted, the raw material adding system 2 is used to add silicon dioxide material into the storage chamber to achieve a reaction between the silicon melt and the solid silicon dioxide under vacuum.

[0043] The silicon dioxide raw material is replenished by continuous slow replenishment or intermittent replenishment. The steps of intermittent replenishment are: adding-stopping-adding. The specific feeding speed is determined according to the inner diameter of the crucible 12.

[0044] S5: Start the collection system 4 to absorb the volatile products in the storage chamber and collect the condensed products.

[0045] S6: When the silicon melt in the crucible 12 is consumed to a set amount, stop adding silicon dioxide, and add silicon material to the storage chamber. After the silicon material is melted, stop adding silicon material, and then slowly and continuously add silicon dioxide again, and repeat this cycle.

[0046] A small amount of raw materials is reserved in the crucible 12 before each cycle, and a small amount of silicon melt is retained in the crucible 12 to have a melting depth of 20-40 mm.

[0047] The present invention also provides a more specific embodiment to explain the above steps S1-S6. Step 1: Assemble the above subsystems according to the corresponding assembly relationship, load the finer silica raw material into the silica raw material bin 21, load the coarser silicon raw material into the silicon material bin 22, and pre-place part of the silicon raw material into the corundum crucible 12; Step 2: close the first discharge valve 23 corresponding to the silicon dioxide raw material bin 21, the second discharge valve 24 corresponding to the silicon material bin 22, the crucible cover 14 and the furnace cover 13, and start the vacuum pump 42 to extract the vacuum until the vacuum degree in the furnace reaches below 10Pa; Step 3: Turn on the medium frequency induction heating power supply 31 to supply power to the induction coil 32, and gradually increase the power until the silicon raw material preset in the corundum crucible 12 is completely melted; Step 4: Open the first discharge valve 23, and slowly add silicon dioxide raw material into the corundum crucible 12 through the first discharge pipe 25 and the material combining pipe 27, so as to realize the solid-liquid reaction (Si+SiO2→SiO↑) of silicon melt and solid silicon dioxide raw material under vacuum, and generate silicon dioxide gas; Step 5: Start the cooling water circulation system of the water-cooled collection barrel 41, and use the extraction function of the vacuum pump 42 to realize the condensation and collection of the reaction product (gaseous silicon dioxide) on the inner wall of the water-cooled collection barrel 41; Step 6: When the silicon melt in the corundum crucible 12 is consumed (a small portion is retained), the first discharge valve 23 is closed, the addition of silicon dioxide raw material is stopped, and the second discharge valve 24 is opened at the same time to replenish silicon raw material into the corundum crucible 12; when the silicon raw material to be replenished is completely melted and the silicon molten pool in the corundum crucible 12 returns to the original liquid level (melting depth of about 100 mm), the second discharge valve 24 is closed, and the first discharge valve 23 is reopened to slowly replenish silicon dioxide raw material into the molten pool to continue the solid-liquid reaction to produce silicon dioxide products; Step 7: When the water-cooled collection barrel 41 is almost full, close the butterfly valve 47, turn off the vacuum pump 42, and then quickly unload and replace the water-cooled collection barrel 41; after the new water-cooled collection barrel 41 is assembled, open the vacuum pump 42 to extract the air in the collection barrel, then open the butterfly valve 47 and the cooling water system of the water-cooled collection barrel 41, and collect the silicon dioxide product again. This cycle is repeated to achieve continuous, efficient and low-cost preparation of silicon dioxide.

[0048] The present invention has a smelting storage system 1, a raw material feeding system 2, an electromagnetic heating system 3 and a collecting system 4. The electromagnetic heating system 3 adopts electromagnetic induction heating. The raw material feeding system 2 can continuously feed raw materials into the storage chamber without destroying the vacuum state of the smelting storage system 1. The condensation vacuum chamber of the collecting system 4 can absorb the volatile gas products in the storage chamber, and collect the volatile products by condensation, so as to realize the quick replacement of the collecting barrel without destroying the vacuum condition. The raw material feeding system 2 can also be used to continuously feed raw materials to continuously carry out the production and preparation of silicon oxide, so that the present scheme prepares silicon oxide by solid-liquid reaction, continuous feeding and quick replacement of the collecting barrel without destroying the vacuum condition, which is beneficial to the improvement of silicon oxide production efficiency.

[0049] The present invention adopts solid-liquid reaction (i.e., reaction of silicon melt with relatively fine solid silicon dioxide raw material) to prepare silicon iodine, thereby eliminating the limitation of the original solid-solid reaction on the particle size and mixing uniformity of the raw materials (silicon and silicon dioxide), and relatively coarse raw materials can be used without mixing, which is beneficial to reducing the cost of preparing silicon iodine.

[0050] The device proposed in this scheme has a compact structure, is safe and reliable, and occupies a small area; the proposed method is highly operational and economical.

[0051] In the description of the present application, it should be noted that the terms "upper" and "lower" and the like 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 application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise expressly specified and limited, 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 an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0052] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0053] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A device for preparing silicon dioxide, characterized in that: include: A smelting material storage system, wherein the smelting material storage system has a storage cavity for containing materials; A raw material feeding system, wherein the raw material feeding system has a plurality of collecting bins connected to the discharge cavity for feeding raw materials into the storage cavity; An electromagnetic heating system, which is arranged outside the smelting storage system and is used to heat the material inside the storage cavity; and The collecting system has a condensing vacuum chamber in the interior thereof which is connected with the material storage chamber, and the condensing vacuum chamber is used for absorbing the volatile products in the material storage chamber and collecting the volatile products by condensation.

2. The device for preparing silicon 2 oxide according to claim 1, characterized in that: The smelting material storage system includes a furnace body, a crucible and an insulation layer. The crucible is arranged inside the furnace body and is used to contain the melt; The heat-insulating layer is coated on the outside of the crucible.

3. The device for preparing silicon 2 oxide according to claim 2, characterized in that: The furnace body is provided with an observation window and a vacuum gauge, the observation channel of the observation window extends to the inside of the crucible and is connected with the inside of the crucible, and the monitoring end of the vacuum gauge is arranged inside the furnace body for measuring the vacuum degree inside the furnace body.

4. The device for preparing silicon 2 oxide according to claim 1, characterized in that: The silo of the raw material feeding system includes a silicon dioxide raw material silo and a silicon silo, wherein the silicon dioxide raw material silo and the silicon silo are used to contain silicon dioxide raw material and silicon raw material respectively; The raw material dosing system also includes a first unloading pipe, a second unloading pipe, a first unloading valve, and a second unloading valve. The silicon dioxide raw material bin is connected to the interior of the storage cavity through the first unloading pipe, and the first unloading pipe is equipped with a first unloading valve. The silicon material bin is connected to the interior of the storage cavity through the second unloading valve, and the second unloading pipe is equipped with a second unloading valve.

5. The device for preparing silicon 2 oxide according to claim 2, characterized in that: The electromagnetic heating system includes a medium frequency induction heating power supply, an induction coil and a graphite heater. The induction coil is arranged around the outside of the crucible and is connected to the output electrode of the medium frequency induction heating power supply to generate an alternating electromagnetic field required for heating the material; The graphite heater is located inside the induction coil and is used for the initial melting of silicon material. The graphite heater adopts an open-slit structure so that the electromagnetic field can penetrate into the graphite heater, directly act on the silicon material after melting to heat it, and use the penetrated electromagnetic field to stir the silicon melt.

6. The device for preparing silicon 2 oxide according to claim 1, characterized in that: The collection system includes a water-cooled collection bucket and a vacuum pump; The water-cooled collection barrel is connected to the storage chamber through a heat-insulating pipe and is used for condensation and sublimation collection of volatile products; The vacuum pump is connected to the water-cooled collection barrel through a vacuum tube, and is used to maintain the reaction vacuum and extract the volatile reaction products into the water-cooled collection barrel.

7. The device for preparing silicon 2 oxide according to claim 6, characterized in that: A filter screen is arranged in the vacuum tube.

8. A method for preparing silicon dioxide, characterized in that: The device for preparing silicon monoxide according to any one of claims 1 to 7, wherein the method comprises: S1: Assemble the subsystems according to the corresponding assembly relationship, respectively load granular silicon material and silicon dioxide material into the two collecting bins of the raw material feeding system, and pre-place part of silicon material in the storage cavity of the smelting storage system; S2: Close the material port of the smelting storage system and start the vacuum pump to extract vacuum; S3: Turn on the electromagnetic heating system to heat the silicon material in the storage chamber; S4: After the silicon material in the storage chamber is completely melted, the silicon dioxide material is added to the storage chamber by using the raw material feeding system to achieve the reaction between the silicon melt and the solid silicon dioxide under vacuum; S5: Start the collection system to absorb the volatile products in the storage chamber and collect the condensation of the volatile products; S6: When the silicon melt in the crucible is consumed to a set amount, stop adding silicon dioxide, and add silicon material to the storage chamber. After the silicon material is melted, stop adding silicon material, and then continuously add silicon dioxide material again, and repeat this cycle.

9. The method for preparing silicon 2 oxide according to claim 8, characterized in that: In step S1, the size of the granular silicon material is 2-20 mesh, and the size of the granular silicon dioxide is 40-100 mesh.

10. The method for preparing silicon 2 oxide according to claim 8, characterized in that: In step S4, the silicon dioxide raw material is replenished by continuous replenishment or intermittent replenishment. The steps of intermittent replenishment are: feed-stop-feed.

Images