Oriented crystallization impurity removal method of metal silicon, application of oriented crystallization impurity removal method and oriented crystallization impurity removal production line
Through the directional crystallization and impurity removal method, the problem of difficulty in removing impurities such as Fe in the prior art is solved, and the preparation of high-purity metal silicon is realized, which reduces production costs and expands the source of raw materials.
Patent Information
- Application Number
- CN202411727184.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2025-02-28
AI Technical Summary
In the existing metal silicon smelting process, it is difficult to effectively remove impurities such as Fe, resulting in high iron impurities content in the finished product, affecting product performance and application space, and increasing production costs.
By adopting the directional crystallization removal method, a high-purity silicon ingot was obtained by quickly pouring liquid silicon into the container and blowing air to cool at the lower part of the container, so that the impurities float on the liquid silicon, and then cooling and removing impurities, a high-purity silicon ingot was obtained.
Effectively remove impurities such as Fe, Al, Ca, B, and P, which reduces the requirements for raw materials, reduces production costs, expands the source of raw materials, and improves the purity and performance of the product.
Smart Images
Figure CN119528149A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of metal silicon hot furnace smelting, and in particular to a directional crystallization impurity removal method for metal silicon, an application thereof and a directional crystallization impurity removal production line. Background Art
[0002] Industrial silicon products have a large application space in the existing manufacturing industry and are in great demand. However, the existing metal silicon smelting process is to refine the liquid silicon smelted in the ore-heat furnace by blowing oxygen in a silicon tank to remove some Ca and Al impurities, and then directly pour the liquid silicon into a cast iron ingot mold, cool and solidify naturally to form silicon plates, and then break them manually or mechanically into blocks of 60-120 mm.
[0003] Such solidification process has obvious defects, mainly including the following points: First, during the process of oxygen blowing refining, only some impurities such as Ca and Al can be removed, but Fe cannot be removed. Therefore, the impurity content of the obtained metallic ferrosilicon is relatively high, which affects the performance and application space of the product, thereby reducing the production economic benefits of the enterprise. Second, in the method of cast iron ingot mold, the iron in the cast iron ingot mold will increase the content of iron impurities. Third, the Fe content is unevenly distributed during the solidification of silicon liquid, and the component segregation is heavy, which makes the quality control of the product a difficult problem, and will bring disputes and other problems to the enterprise in subsequent sales and other links. Fourth, the existing methods for removing impurities from metallic silicon are difficult to effectively remove iron, but metallic silicon is graded and priced according to Fe, Al, and Ca impurities. Therefore, there is a lack of good impurity removal methods. It can only start from the selection of initial materials and select raw materials with low iron impurity content, but such raw materials are relatively scarce and resources are gradually exhausted; and compared with ordinary raw materials, the price is high, the production cost of the enterprise is very high, and in the long run, the high-purity raw material silica is consumed a lot, and the silica raw material resources with high impurity content are also difficult to use. Whether the industry can achieve sustainable development has hidden dangers. Summary of the invention
[0004] The purpose of the present invention is to solve the problem that the iron impurity content in the finished product of the existing metal silicon smelting is high and difficult to remove. The present invention provides a directional crystallization impurity removal method for metal silicon, its application and directional crystallization impurity removal production line, which can remove the Fe element that cannot be removed by the existing process, and remove impurities such as Al, Ca, B, P, etc. Even if raw materials such as silica and clean coal with high Fe, Al, Ca, B and P content are used, after smelting into silicon liquid, most of the impurities can be removed by the preparation method of the present invention, thereby reducing the requirements for raw materials such as silica and clean coal, reducing the production cost of the enterprise and expanding the source of raw materials.
[0005] First, the present invention provides a method for directional crystallization and impurity removal of metallic silicon, comprising the following steps: S1, taking raw materials and smelting them in an electric arc furnace to obtain liquid silicon; S2, quickly pouring the liquid silicon from the electric arc furnace into a container, and covering the upper part of the container for insulation; S3, blowing air to cool the lower part of the container, so that the liquid silicon in the container slowly cools from bottom to top, and Fe, Al, Ca, B, and P impurities always float on the upper part of the liquid silicon. After a predetermined time, the liquid silicon is completely cooled to form a cooled solid silicon ingot; S4, separating the container from the solid silicon ingot, and cutting and removing a preset part of the upper part of the solid silicon ingot to obtain a finished high-purity silicon ingot.
[0006] Furthermore, in S2, liquid silicon is poured into the container at the fastest speed achievable in production.
[0007] Furthermore, in S2, the bottom of the container is a graphite plate with an anti-oxidation coating.
[0008] Furthermore, in S2, the container is an integrally formed two-layer structure with a refractory material inside and a steel material outside.
[0009] Furthermore, in S3, the method of blowing air to cool the lower part of the container is to provide a cooling gas source and a nozzle, and the nozzle is arranged at the lower part of the container.
[0010] Furthermore, in said S3, the flow rate of the cooling gas for air blowing cooling is controlled to be 0.5-10 m / s; in special cases, the air jet can be stopped, that is, the gas flow rate is 0.0 m / s.
[0011] Furthermore, in S3, the predetermined time is 60 to 240 minutes.
[0012] Furthermore, in S4, the height of the cut and removed portion is 5 to 20 mm.
[0013] Secondly, the present invention also provides a directional crystallization and impurity removal production line for metallic silicon, comprising an ore-blast furnace, an impurity removal and crystallization line connected to a silicon outlet trough of the ore-blast furnace, a discharging device and an impurity removal device, wherein the impurity removal and crystallization line comprises a track and several containers slidably arranged on the track, the ore-blast furnace discharges liquid silicon and pours it into a first container through a silicon outlet trough, after the pouring is completed, the first container moves, and an adjacent second container moves to the position of the first container and is connected to the silicon outlet trough, the ore-blast furnace discharges liquid silicon again and pours it into a second container through the silicon outlet trough, and subsequent containers repeat the above operation, so that several containers on the track are all poured with liquid silicon, and cooled to obtain solid silicon ingots; the discharging device is used to separate containers and solid silicon ingots, and the impurity removal device is used to remove the impurity layer on the top of the solid silicon ingot to obtain a finished product.
[0014] In addition, the present invention also provides an application of the above-mentioned method for directional crystallization and impurity removal of metallic silicon, which is applied in the smelting of metallic silicon in a mineral arc furnace.
[0015] Compared with the prior art, the advantages of the present invention are:
[0016] 1. The method for removing impurities from the directional crystallization of metallic silicon involved in the present invention can remove the Fe element that cannot be removed by the existing process, and remove impurities such as Al, Ca, B, and P at the same time. Even if raw materials such as silica and clean coal with high contents of Fe, Al, Ca, B, and P are used, after smelting into silicon liquid, most of the impurities can be removed by the preparation method of the present invention, thereby reducing the requirements for raw materials such as silica and clean coal, reducing the production cost of the enterprise, and expanding the source of raw materials, which has strong advantages.
[0017] 2. The directional crystallization and impurity removal production line of metallic silicon involved in the present invention has a simple structure, low construction difficulty and a wide range of applications.
[0018] The production process of this production line is as follows: the user places the smelted raw materials into the ore-fired furnace, operates the smelting, obtains liquid silicon after smelting, pours the liquid silicon into the first container through the silicon outlet trough, and after the first container is filled, the first container moves on the track so that the second container is connected to the silicon outlet trough. At this time, the liquid silicon in the ore-fired furnace is introduced into the second container, and the subsequent containers repeat the above operation so that all several containers are poured with liquid silicon and begin to cool slowly. After the cooling is completed, a removal device is used to separate each container from the solid silicon ingot to obtain several solid silicon ingots. The impurity removal device is operated to scrape off the impurity layer on the top of the solid silicon ingot to obtain a high-purity silicon package, and the preparation of multiple high-purity silicon packages is completed. The production line of the present invention can produce multiple high-purity silicon packages within a certain period of time. The production line has a simple structure and high production efficiency. At the same time, it can effectively remove impurities and has strong advantages.
[0019] 3. The application of the directional crystallization impurity removal method of metallic silicon involved in the present invention is simple, can reduce the requirements for smelting raw materials, reduce production costs, and has a broad application space. It has positive significance for reducing costs and increasing efficiency of enterprise production and effectively utilizing natural ore resources. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The present invention is a schematic diagram of a method for directional crystallization and impurity removal of metallic silicon.
[0021] Figure 2 It is a schematic structural diagram of the container of the present invention.
[0022] Figure 3 The structure of a directional crystallization and impurity removal production line of metallic silicon according to the present invention is shown in FIG. Figure 1 .
[0023] Figure 4 The structure of a directional crystallization and impurity removal production line of metallic silicon according to the present invention is shown in FIG. Figure 2 .
[0024] The attached figure is marked with: 1-submerged arc furnace, 2-silicon outlet trough, 3-first container, 4-second container, 5-trolley, 6-track.
[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.
[0026] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. DETAILED DESCRIPTION
[0027] First, an embodiment of the present invention provides a method for removing impurities from directional crystallization of metallic silicon. Figure 1 , including the following steps: S1, taking raw materials and smelting them in an ore-heat furnace to obtain liquid silicon; S2, quickly pouring the liquid silicon from the ore-heat furnace into a container, and covering the upper part of the container for insulation; S3, blowing air to cool the lower part of the container, so that the liquid silicon in the container slowly cools from bottom to top, and the impurities of Fe, Al, Ca, B, and P always float on the upper part of the liquid silicon. After a predetermined time, the liquid silicon is completely cooled to form a cooled solid silicon ingot; S4, separating the container from the solid silicon ingot, and cutting and removing a preset part of the upper part of the solid silicon ingot to obtain a finished high-purity silicon ingot.
[0028] It can be understood that the impurity removal method of the present invention can remove the Fe element that cannot be removed by the existing process, and at the same time remove impurities such as Al, Ca, B, and P. Even if raw materials such as silica and clean coal with high Fe, Al, Ca, B, and P content are used, after smelting into silicon liquid, most of the impurities can be removed by the preparation method of the present invention, thereby reducing the requirements for raw materials such as silica and clean coal, reducing the production cost of the enterprise, and expanding the source of raw materials, which has a strong advantage.
[0029] Specifically, the liquid silicon obtained by smelting in the electric arc furnace is quickly introduced into the container to avoid slow pouring so that the liquid silicon has solidified. At the same time, the container is covered to keep it warm, and the temperature in the container is maintained to facilitate the removal of impurities. During the cooling process, the lower part of the container is blown to cool the liquid silicon in the container slowly from bottom to top. During this cooling process, the blown gas reacts with iron to form oxides. Since the oxides are lighter than liquid silicon, they always float on the upper part of the liquid silicon. After a certain period of time, the liquid silicon is completely cooled from bottom to bottom to form a cooled solid silicon ingot, and the impurities of the iron oxide are always on the upper part of the silicon package, even after cooling and solidification, they are still on the top, realizing the collection of impurities. Therefore, in the subsequent process, the container is removed to expose the complete solid silicon ingot, and the upper part of the solid silicon ingot is removed by a mechanical device, so that the impurities are effectively removed, and a high-purity silicon package with a large amount of impurities removed is obtained.
[0030] It should be noted that, due to the good impurity removal effect in this case, the selection of ore materials in S1 is more diverse, and raw materials with higher iron impurity content can also meet production needs.
[0031] In some embodiments of the present invention, in S2, the liquid silicon is poured into the container at the fastest speed achievable in production. It is understandable that controlling the pouring speed of the liquid silicon to be extremely fast can minimize the temperature drop of the liquid silicon during the pouring process.
[0032] In certain embodiments of the present invention, in S2, the bottom of the container is a graphite plate with an anti-oxidation coating to prevent oxidation of the graphite plate and increase its service life.
[0033] In certain embodiments of the present invention, please refer to Figure 1 and Figure 2 In S2, the container is an integrally formed two-layer structure, the inner part is made of refractory material, and the outer part is made of steel. Such a structure can well prevent heat from escaping from the four walls and the top of the container, thereby achieving a better impurity removal effect. The outer steel material can give the container sufficient mechanical strength.
[0034] In certain embodiments of the present invention, in S3, the method of blowing air to cool the lower part of the container is to provide a cooling gas source and several nozzles connected to the cooling gas source, and place the cooling gas source at the lower part of the container through the nozzles, thereby achieving slow cooling of the liquid in the container.
[0035] In certain embodiments of the present invention, in S3, the flow rate of the cooling gas for air blowing cooling is controlled to be 0.5-10 m / s; in special cases, the air jet can be stopped, that is, the gas flow rate is 0.0 m / s.
[0036] In some embodiments of the present invention, in S3, the predetermined time is 60 to 240 minutes.
[0037] In some embodiments of the present invention, in S4, the height of the cut and removed portion is 5 to 20 mm.
[0038] The present invention also provides a directional crystallization and impurity removal production line for metallic silicon. Figure 3 and Figure 4 , comprising an ore-fired furnace 1, an impurity removal crystallization line connected to a silicon outlet trough 2 of the ore-fired furnace, a discharging device and an impurity removal device, the impurity removal crystallization line comprising a track 6 and a plurality of containers slidably arranged on the track 6, the ore-fired furnace discharges liquid silicon and pours it into a first container 3 through a silicon outlet trough, after the pouring is completed, the first container 3 moves, and an adjacent second container 4 moves to the position of the first container 3 and is connected to the silicon outlet trough, the ore-fired furnace discharges liquid silicon again and pours it into the second container 4 through the silicon outlet trough, and the subsequent containers repeat the above operation, so that the plurality of containers on the track are all poured with liquid silicon, and cooled to obtain solid silicon ingots; the discharging device is used to separate containers and solid silicon ingots, please refer to Figure 1 The impurity removal device is used to remove the impurity layer on the top of the solid silicon ingot to obtain a finished product.
[0039] It can be understood that the directional crystallization impurity removal production line of metallic silicon involved in the present invention has a simple structure, low difficulty in construction, and a wide range of applications. The production process of this production line is: the user places the smelted raw materials into the submerged arc furnace, operates the smelting, obtains liquid silicon after smelting, pours the liquid silicon into the first container through the silicon outlet trough, and after the first container is filled, the first container moves on the track so that the second container is connected to the silicon outlet trough. At this time, the liquid silicon in the submerged arc furnace is introduced into the second container, and the subsequent containers repeat the above operation so that all several containers are poured with liquid silicon and begin to cool slowly. After the cooling is completed, each container is separated from the solid silicon ingot using a removal device to obtain several solid silicon ingots, and the impurity removal device is operated to scrape off the impurity layer on the top of the solid silicon ingot to obtain a high-purity silicon package, completing the preparation of multiple high-purity silicon packages. The production line of the present invention can produce multiple high-purity silicon packages within a certain period of time. The production line has a simple structure and high production efficiency, and can effectively remove impurities at the same time, and has strong advantages.
[0040] In certain embodiments of the present invention, the unloading device can be a motor-driven mechanical gripper, which is detachably connected to the periphery of the container. When the container and the solid silicon ingot need to be unloaded, the motor is turned on, and the motor drives the mechanical gripper to grab the container, thereby achieving separation of the container.
[0041] In certain embodiments of the present invention, the impurity removal device may be a cutting tool driven by a motor. When the solid silicon ingot is removed from the container, the motor is turned on to drive the cutting tool to remove the impurity layer on the top of the solid silicon ingot, thereby removing the impurities. It should be noted that the removal device and the impurity removal device are both prior art. As long as the separation of the solid silicon ingot and the container can be achieved, any means or device for removing the impurity layer on the top of the solid silicon ingot can achieve the effect of this case.
[0042] The present invention also provides an application of the above-mentioned method for removing impurities from directional crystallization of metallic silicon, which is applied in the smelting of metallic silicon in a mineral arc furnace. It can be understood that the method of the present invention is simple, can reduce the requirements for smelting raw materials, reduce production costs, and has a broad application space. It has positive significance for reducing costs and increasing efficiency of enterprise production and effectively utilizing the mineral resources of nature.
[0043] Example 1
[0044] In this embodiment, a directional crystallization impurity removal method is used in the smelting process of metal silicon of a certain enterprise. Figure 1 , including the following steps: S1, take the raw materials and carry out smelting in a mineral furnace to obtain liquid silicon; S2, quickly pour the liquid silicon from the mineral furnace into a container, and cover the upper part of the container for insulation; S3, blow air to cool the lower part of the container, so that the liquid silicon in the container slowly cools from bottom to top, and impurities such as Fe, Al, Ca, B, P always float on the upper part of the liquid silicon. After a predetermined time, the liquid silicon is completely cooled to form a cooled solid silicon ingot; S4, separate the container from the solid silicon ingot, and remove the preset part of the upper part of the solid silicon ingot to obtain a finished high-purity silicon ingot. The container is an integrally formed two-layer structure with a refractory material inside and a steel material outside. In S3, the method of blowing air to cool the lower part of the container is to provide a cooling gas source and several nozzles connected to the cooling gas source, and place the cooling gas source at the lower part of the container through the nozzle, so as to achieve slow cooling of the liquid in the container. In S2, the liquid silicon is poured into the container at the fastest speed that can be achieved in production. In the step S3, the flow rate of the cooling gas for air blowing cooling is controlled to be 0.5 m / s. In the step S3, the predetermined time is 240 minutes. In the step S4, the height of the preset removal portion is 10 mm.
[0045] Example 2
[0046] In this embodiment, a directional crystallization and impurity removal production line 1 for metallic silicon is provided. Figure 3 and Figure 4, comprising an ore-heating furnace 1, an impurity removal crystallization line connected to a silicon outlet trough 2 of the ore-heating furnace 1, a discharging device and an impurity removal device, the impurity removal crystallization line comprising a track and several containers slidably arranged on the track 6, the ore-heating furnace discharges liquid silicon and pours it into a first container 3 through a silicon outlet trough, after the pouring is completed, the first container 3 moves, and the adjacent second container 4 moves to the position of the first container 3 and is connected to the silicon outlet trough, the ore-heating furnace discharges liquid silicon again and pours it into the second container 4 through the silicon outlet trough, and the subsequent containers repeat the above operation, so that several containers on the track are all poured with liquid silicon, and cooled to obtain solid silicon ingots; the discharging device is used to separate containers and solid silicon ingots, please refer to Figure 1 The impurity removal device is used to scrape off the impurity layer on the top of the solid silicon ingot to obtain a finished product.
[0047] Example 3
[0048] Based on Example 2, this example provides a directional crystallization impurity removal production line 2 for metallic silicon. Figure 3 and Figure 4 The production line also includes a plurality of trolleys 5 slidingly arranged on the track 6, the trolleys 5 are connected front and back, and each trolley is provided with a container. After the production starts, the trolley 5 is driven to slide on the track 6 to realize the movement of the container, so that the container is sequentially loaded with liquid silicon for cooling. At the same time, the bottom of the trolley is connected to a cooling gas source, so that the cooling gas source cools the graphite plate at the bottom of the container.
[0049] The above embodiment is only one implementation of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.
Claims
1. A method for removing impurities from directional crystallization of metallic silicon, characterized in that: The following steps are involved: S1. Take the raw materials and smelt them in an electric arc furnace to obtain liquid silicon; S2. Quickly pour the liquid silicon from the electric arc furnace into a container, and cover the upper part of the container to keep it warm; S3. Blow air to cool the lower part of the container, so that the liquid silicon in the container slowly cools from bottom to top, and the impurities of Fe, Al, Ca, B, and P always float on the upper part of the liquid silicon. After a predetermined time, the liquid silicon is completely cooled to form a cooled solid silicon ingot; S4. Separate the container from the solid silicon ingot, and cut and remove a preset part of the upper part of the solid silicon ingot to obtain a finished high-purity silicon ingot.
2. The method for removing impurities from directional crystallization of metallic silicon according to claim 1, characterized in that: In S2, liquid silicon is poured into the container at the fastest speed achievable in production.
3. The method for removing impurities from directional crystallization of metallic silicon according to claim 1, characterized in that: In S2, the bottom of the container is a graphite plate with an anti-oxidation coating.
4. The method for removing impurities from directional crystallization of metallic silicon according to claim 1, characterized in that: In S2, the container is an integrally formed two-layer structure with a refractory material inside and a steel material outside.
5. The method for removing impurities from directional crystallization of metallic silicon according to claim 1, characterized in that: In S3, the method of blowing air to cool the lower part of the container is to provide a cooling gas source and a nozzle, and the nozzle is arranged at the lower part of the container.
6. The method for removing impurities from directional crystallization of metallic silicon according to claim 5, characterized in that: In S3, the flow rate of the cooling gas for air blowing cooling is controlled to be 0.5-10 m / s. In special cases, the air jet can be stopped, that is, the gas flow rate is 0.0 m / s.
7. The method for removing impurities from directional crystallization of metallic silicon according to claim 1, characterized in that: In S3, the predetermined time is 60 to 240 minutes.
8. The method for removing impurities from directional crystallization of metallic silicon according to claim 1, characterized in that: In the above S4, the height of the cut and removed portion is 5 to 20 mm.
9. A directional crystallization and impurity removal production line for metallic silicon, characterized in that: The invention comprises an ore-blast furnace, an impurity removal crystallization line connected to a silicon outlet trough of the ore-blast furnace, a discharging device and an impurity removal device. The impurity removal crystallization line comprises a track and several containers slidably arranged on the track. The ore-blast furnace discharges liquid silicon and pours it into a first container through a silicon outlet trough. After the pouring is completed, the first container moves, and an adjacent second container moves to the position of the first container and is connected to the silicon outlet trough. The ore-blast furnace discharges liquid silicon again and pours it into a second container through the silicon outlet trough. Subsequent containers repeat the above operation, so that several containers on the track are all poured with liquid silicon, and cooled to obtain solid silicon ingots. The discharging device is used to separate containers and solid silicon ingots, and the impurity removal device is used to remove the impurity layer on the top of the solid silicon ingot to obtain a finished product.
10. Application of a method for removing impurities from directional crystallization of metallic silicon according to any one of claims 1 to 8, characterized in that: Used in the smelting of metallic silicon in ore-fired furnaces.