Silicon core production equipment

Abstract

The utility model provides silicon core production equipment, and relates to the technical field of silicon core production. The silicon core production equipment comprises at least one furnace body, an induction heater, a plurality of crucibles, a preheater, a lifter and a furnace wall, a furnace chamber is defined by the furnace wall, the induction heater is installed in the furnace chamber, one side of the induction heater is in sliding connection with the furnace wall, the induction heater is provided with a through hole, and the through hole is communicated with the crucible. The induction heater is provided with a through hole, the crucibles penetrate through the through hole of the induction heater, the preheaters are distributed on the peripheral side of the crucibles, the lifters are arranged corresponding to the crucibles, and the end part of each crucible is connected with one lifter. The silicon cores with different diameters can be directly generated, cutting loss is not needed, the generation cost is lower, and the generation efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of silicon core production, and in particular to a silicon core production device. Background Art

[0002] Silicon is one of the most important basic materials for modern technology. At present, the modified Siemens method is widely used to prepare high-purity polysilicon, and silicon cores are used in the reduction process of polysilicon. Silicon cores can be divided into two types according to different production processes: zone melting silicon cores and cut silicon cores. Zone melting silicon cores are round silicon cores with a circular cross section obtained by drawing pre-prepared raw material rods through zone melting process in zone melting equipment. Cut silicon cores are obtained by cutting larger straight-pulled silicon core rods through diamond wire mesh to obtain multiple small-sized square silicon cores with a square cross section.

[0003] Compared with round silicon cores, square silicon cores have the advantages of large production capacity, consistent size specifications, and low reduction furnace rod failure rate. The processing flow of cutting square silicon cores mainly includes head and tail removal, cutting, taper grinding, drilling, cleaning, drying and other processes. Hidden cracks are prone to occur during the processing, and the processes are numerous and the manufacturing cost is high. For this reason, a silicon core production device is provided. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a silicon core production equipment, aiming to solve the technical problems in the prior art that the silicon core production process is complex and has high losses.

[0005] To achieve the above objectives, the technical solutions adopted in this application are as follows:

[0006] In a first aspect, an embodiment of the present application provides a silicon core production device, including:

[0007] At least one furnace body, the furnace body comprising a furnace wall, the furnace wall enclosing a furnace chamber;

[0008] An induction heater, wherein the induction heater is installed in the furnace chamber, and one side of the induction heater is slidably connected to the furnace wall;

[0009] at least one crucible, the induction heater is provided with a through hole, and the crucible passes through the through hole of the induction heater;

[0010] A preheater, the preheater being distributed around the crucible;

[0011] A lifter is provided corresponding to the crucible, and the end of each crucible is connected to one of the lifters.

[0012] In one of the embodiments of the first aspect, the silicon core production equipment further includes a storage chamber, and the storage chamber is connected to an end of the furnace body away from the lifter.

[0013] In one of the embodiments of the first aspect, a plurality of discharge pipes are provided on one side of the storage chamber connected to the furnace body, each of the discharge pipes corresponds to one of the crucibles, and the discharge pipes are provided with a feeding switch.

[0014] In one of the embodiments of the first aspect, an air inlet is provided at one end of the furnace body close to the material storage chamber, and an exhaust port is provided at a side of the furnace body away from the material storage chamber.

[0015] In one of the embodiments of the first aspect, the induction heater comprises a plurality of sub-induction heaters and a bracket, the plurality of sub-induction heaters are mounted on the bracket, and one side of the bracket is connected to the furnace wall.

[0016] In one of the embodiments of the first aspect, the furnace wall is provided with a lifting mechanism, and the lifting mechanism controls the lifting movement of the bracket in the furnace chamber.

[0017] In one of the embodiments of the first aspect, a heat insulation plate is provided on a side of the induction heater close to the pre-heater.

[0018] In one embodiment of the first aspect, the crucible includes a plurality of petals, two adjacent petals are spliced ​​together, and a cooling channel is disposed in the petal.

[0019] In one embodiment of the first aspect, the preheater includes an external heater and an internal heater, the external heater frame is arranged on the outside of the internal heater, a crucible is arranged in the internal heater, and a plurality of crucibles are arranged between the external heater and the internal heater.

[0020] In one embodiment of the first aspect, the silicon core production equipment includes four furnace bodies, each of which is provided with a furnace door.

[0021] In a second aspect, the present application also provides a silicon core production method, including:

[0022] The lifter drives the crucible down until the bottom of the crucible reaches the heating zone of the preheater, polysilicon material is added to the crucible, and the furnace chamber is evacuated. After the vacuum degree reaches the set value, high-purity inert gas is filled into the vacuum furnace chamber and the exhaust port is opened;

[0023] The preheater heats the bottom of the crucible, and when the temperature of the polysilicon material rises to the set temperature, the heating is stopped;

[0024] The lifter drives the crucible to rise until the bottom of the crucible is out of the heating zone of the heater, and the induction heater is lowered to the corresponding area of ​​the crucible for preheating treatment;

[0025] Start the induction heater for heating. After all the existing polysilicon materials in the crucible are melted, add polysilicon materials to the crucible, and simultaneously raise the induction heater while adding materials. The polysilicon materials under the induction heater are cooled and solidified until the growth of silicon rods is completed.

[0026] The silicon rod is taken out, and after mechanical processing, cleaning and drying, a silicon core is obtained.

[0027] Compared with the prior art, the beneficial effect of the present application is that the present application provides a silicon core production device, which can be used for the directional solidification process production of silicon cores. The silicon core production equipment includes at least one furnace body, an induction heater, at least one crucible, a preheater and a lifter. The induction heater is installed in the furnace chamber of the furnace body, and one side of the induction heater is connected to the furnace wall. The crucible is provided with an induction heater, and the preheater is distributed on the surrounding side of the crucible. The lifter is connected to the end of the crucible. In this way, the lifting height of the crucible can be controlled by the lifter. Before the directional solidification of the silicon core is generated, the bottom of the crucible is located within the heating range of the preheater, so that the silicon material at the bottom of the crucible is preheated and raised to a temperature that can be inductively heated. Then, the rising crucible makes the silicon material that reaches the induction heating temperature in the heating range of the induction heater, so that the silicon material is heated and melted. After the silicon material at the bottom of the crucible is melted, cold silicon material is continuously added, and the induction heater rises synchronously at the same time. The silicon material below, away from the induction heater, cools and solidifies until a complete silicon material is generated. The present application can directly generate silicon cores of different diameters as required, without cutting loss, lower generation cost, and improved generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 The structure of the silicon core production equipment in some embodiments of the present application is shown Figure 1 ;

[0030] Figure 2 The structure of the silicon core production equipment in some embodiments of the present application is shown Figure 2 ;

[0031] Figure 3 A schematic diagram of the structure of an induction heater in some embodiments of the present application is shown;

[0032] Figure 4 The schematic diagram of the structure of the preheater in some embodiments of the present application is shown. Figure 1 ;

[0033] Figure 5 The schematic diagram of the structure of the preheater in some embodiments of the present application is shown. Figure 2 ;

[0034] Figure 6 A schematic diagram of the structure of a crucible in some embodiments of the present application is shown;

[0035] Figure 7 It shows a schematic diagram of the structure of the petal body in some embodiments of the present application;

[0036] Figure 8 A schematic diagram of the furnace layout structure of silicon core production equipment in some embodiments of the present application is shown;

[0037] Fig. 9 A flow chart of a silicon core production method in some embodiments of the present application is shown.

[0038] Description of main component symbols:

[0039] 100-silicon core production equipment; 110-furnace body; 111-furnace wall; 112-furnace chamber; 113-air inlet; 114-exhaust outlet; 120-induction heater; 121-sub-induction heater; 122-bracket; 123-heat insulation board; 130-crucible; 131-valve body; 140-preheater; 141-external heater; 142-internal heater; 150-lifter; 160-storage chamber; 161-warehouse body; 162-cover body; 163-exhaust port; 164-feed port; 170-discharge pipe; 180-feeding switch. DETAILED DESCRIPTION

[0040] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0041] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" 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, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0043] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0044] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0045] The inventors of the present application have found that, at present, the modified Siemens method is generally used to prepare high-purity polysilicon, and silicon cores are used in the reduction process of polysilicon. The silicon cores in the reduction furnace can be divided into two types: zone melting silicon cores and cut silicon cores according to different production processes. The zone melting silicon core is a silicon core with a diameter of 7-12mm and a length of 2500-3500mm drawn by a zone melting process in a zone melting device using a pre-prepared raw material rod. Because its cross section is circular, it is also called a round silicon core. The cut silicon core is obtained by cutting a straight-pulled silicon core rod through a diamond wire mesh. Because the cross section of the cut silicon core is square, it is also called a square silicon core. Compared with round silicon cores, square silicon cores have the advantages of large production capacity, consistent size specifications, and low reduction furnace rod failure rate. The raw material rods for cutting square silicon cores are mostly straight-pulled silicon core rods. The production of straight-pulled silicon core rods mostly uses a process similar to that of producing single crystal silicon rods, and the silicon core round rods are mostly in a polycrystalline state. After preparing the silicon core round rod, its processing flow mainly includes cutting off the head and tail, cutting, grinding, punching, cleaning, drying and other processes. Hidden cracks are prone to occur during the processing, and the processes are numerous and the manufacturing cost is high.

[0046] Directional solidification is a method of purifying and preparing solar-grade polysilicon by metallurgical methods, in which the use of electromagnetic directional solidification technology is an important means of high efficiency, low energy consumption and low manufacturing cost. However, since silicon is a semiconductor, its conductivity is poor and it cannot be directly melted by induction heating. It needs to be preheated and its temperature rises to a certain temperature, generally believed to be above 700°C, before induction heating can be performed. In addition, since electromagnetic semi-continuous directional solidification is used, during the continuous casting process, if the molten pool is not properly controlled, the molten pool after preheating and melting is still prone to not being able to preheat the subsequent continuous addition of cold silicon materials, which may lead to the molten pool extinguishing and the risk of interruption of the continuous directional solidification process. There is also a method of placing the silicon raw material on a graphite base for induction heating, but this method will introduce impurities such as carbon into the silicon raw material.

[0047] To this end, the embodiments of the present application provide a silicon core production device 100 and a production method thereof, which can be used for the directional solidification process production of silicon cores. The silicon core production device 100 and a production method thereof provided in the present application can directly generate silicon cores of different required diameters without cutting loss, with lower production costs and improved production efficiency.

[0048] like Figure 1 As shown, the embodiment of the present application provides a silicon core production device 100, which includes at least one furnace body 110, an induction heater 120, at least one crucible 130, a preheater 140 and a lifter 150. The furnace body 110 includes a furnace wall 111, which encloses a furnace chamber 112, the induction heater 120 is installed in the furnace chamber 112, and one side of the induction heater 120 is slidably connected to the furnace wall 111, the crucible 130 is penetrated by the induction heater 120, the preheater 140 is distributed around the crucible 130, and the lifter 150 is connected to the end of the crucible 130.

[0049] At least one refers to a natural number greater than one. In the present application, the number of furnace bodies 110 can be one, two, three, four, etc. Figure 8 As shown, in this embodiment, there may be four furnace bodies 110. Each furnace body 110 includes a furnace wall 111 surrounding it, two adjacent furnace bodies 110 may share one furnace wall 111, and a furnace door is provided on one side of the non-shared furnace wall 111 of each furnace body 110, and the furnace walls 111 enclose a furnace chamber 112 for silicon core generation.

[0050] The induction heater 120 is an inductor coil that can meet various heating processes by reasonably distributing the induction magnetic field, and has the advantages of selective local heating, fast heating speed, and high power utilization rate. The furnace wall 111 is provided with a slide groove, and one side of the induction heater 120 can slide along the slide groove of the furnace wall 111 through the lifting structure. Through the setting of the induction heater 120, the part of the silicon core in the heating range is heated and melted. At the same time, during the continuous feeding process of silicon material, the induction heater 120 can slide along the furnace wall 111 to adjust the heating part, so that the silicon material out of the heating range is condensed to form a round silicon rod.

[0051] The number of indexes is a natural number greater than two. In the present application, the number of crucibles 130 in a furnace body 110 can be two, three, four, five, etc., which can be set according to actual production requirements. The inner diameter of the crucible 130 can be selected according to the silicon core specifications to meet the production of silicon cores with different diameters.

[0052] In this embodiment, the height of the crucible 130 can be set to 2000 mm-4000 mm, and the inner diameter can be set to 15 mm-45 mm.

[0053] The preheater 140 can be a graphite heater, and its structure can be arc-shaped. The height of the preheater 140 can be 10%-30% of the height of the crucible 130. The preheater 140 is mounted on the circumference of the crucible 130 to preheat the crucible 130 in the heating range to a temperature above 700°C, at which the silicon material can be induction heated.

[0054] The lifter 150 may be a hydraulic cylinder, a pneumatic cylinder or a linear motor with a lifting function. The telescopic end of the lifter 150 is connected to the bottom end of the crucible 130 to adjust the relative height of the crucible 130 so that the silicon material inside the crucible 130 is in different heating states.

[0055] like Figure 2 As shown, in some embodiments, the silicon core production equipment 100 further includes a storage chamber 160 , and the storage chamber 160 is connected to an end of the furnace body 110 away from the lifter 150 .

[0056] The storage chamber 160 includes a warehouse body 161, a cover body 162, an exhaust port 163 and a feed port 164. The warehouse body 161 can store polysilicon raw materials used to prepare silicon cores, and its storage design weight is greater than 10%-20% of the required silicon core preparation weight. The warehouse body 161 has a conical structure, and the end with a smaller inner diameter is connected to the furnace body 110 to facilitate the rapid unloading of materials. The cover body 162 is covered on the side of the warehouse body 161 away from the furnace body 110. The exhaust port 163 and the feed port 164 are both arranged on the cover body 162. The feed port 164 is used for adding polysilicon materials, and the exhaust port 163 is used for vacuuming the crucible 130 before adding materials.

[0057] Combination Figure 1 and Figure 2 As shown, in some embodiments, a plurality of discharge pipes 170 are provided on one side of the storage chamber 160 connected to the furnace body 110 , each discharge pipe 170 corresponds to a crucible 130 , and a feeding switch 180 is provided on the discharge pipe 170 .

[0058] The number of discharge pipes 170 in each furnace body 110 is the same as the number of crucibles 130, so that each crucible 130 corresponds to a discharge pipe 170, ensuring the synchronous discharge of each crucible 130. One end of the discharge pipe 170 is connected to the warehouse body 161 of the storage chamber 160, and the other end is aligned with the crucible 130, and under the control of the feeding switch 180, the corresponding crucible 130 is fed with materials.

[0059] Furthermore, the feeding switch 180 includes a weighing sensor to calculate the weight of the silicon material passing through the discharge pipe 170, so as to achieve accurate control of the feeding during the silicon core production process, thereby avoiding the risk of excessive addition of cold silicon material, which may cause the molten pool temperature to drop too quickly and extinguish, thereby interrupting the continuous directional solidification process.

[0060] In some embodiments, an air inlet 113 is disposed at one end of the furnace body 110 close to the material storage chamber 160 , and an exhaust port 114 is disposed at a side of the furnace body 110 away from the material storage chamber 160 .

[0061] By setting the exhaust port 114, the furnace chamber 112 can be evacuated before the poly-gold silicon material is filled for preheating. After the vacuum degree reaches the requirement, high-purity inert gas is filled into the furnace chamber 112 at a certain flow rate to improve the heating efficiency and avoid oxidation loss caused by the contact between the material and the air.

[0062] In this embodiment, argon can be selected as the inert gas.

[0063] like Figure 3 As shown, in some embodiments, the induction heater 120 includes a plurality of sub-induction heaters 121 and a bracket 122 . The plurality of sub-induction heaters 121 are all mounted on the bracket 122 , and one side of the bracket 122 is connected to the furnace wall 111 .

[0064] In each furnace body 110, the number of sub-induction heaters 121 is the same as the number of crucibles 130. The support 122 may be a circular ring structure, and a connecting block is provided on one side. The support 122 is connected to the furnace wall 111 through the connecting block, so as to drive the support 122 as a whole and the sub-induction heaters 121 fixed on the support 122 to move synchronously up and down. In order to increase the yield of silicon cores and improve space utilization, a sub-induction heater 121 may be provided in the center of the circular ring, and the other multiple sub-induction heaters 121 are equidistantly distributed around the central sub-induction heater 121.

[0065] In some embodiments, the furnace wall 111 is provided with a lifting mechanism, and the lifting mechanism controls the lifting movement of the bracket 122 in the furnace chamber 112 .

[0066] For example, the lifting mechanism may be a hydraulic cylinder, a hydraulic cylinder or a linear motor transmission structure, etc. The induction heater 120 can be automatically lifted and lowered by a control system or a start switch.

[0067] In some embodiments, a heat insulation plate 123 is disposed on a side of the induction heater 120 close to the pre-heater 140 .

[0068] The heat insulation plate 123 is fixed to the bottom side of the bracket 122 so as to separate the pre-heater 140 from the induction heater 120 and reduce the influence of the heat of the heater on the induction heater 120 .

[0069] Combination Figure 6 and Figure 7 As shown, in some embodiments, the crucible 130 includes a plurality of petals 131 , two adjacent petals 131 are spliced ​​together, and a cooling channel is disposed in the petals 131 .

[0070] In this embodiment, the crucible 130 can be a copper crucible 130, and is divided into a plurality of petals 131 parallel to the axis of the crucible 130. The number of petals 131 can be designed according to the inner diameter of the crucible 130, such as 3-30 petals. The crucible 130 is assembled by combining a plurality of petals 131 so that the electromagnetic field of the induction heater 120 can pass through the wall of the crucible 130 and enter the interior of the crucible 130 to achieve induction heating. A cooling channel is provided in each petal 131, and a water inlet channel and a water outlet channel are provided. Circulating cooling water is introduced into the cooling channel to prevent the crucible 130 from being burned during the heating process.

[0071] In other embodiments, the number of petals 131 is preferably 6-15 petals.

[0072] In addition, the height and inner diameter of the crucible 130 can be designed based on the currently commonly used height and diameter of the silicon core. However, since the silicon core needs to be cut off and the surface silicon powder shell needs to be polished after production, the height and inner diameter of the crucible 130 should be designed to be larger than the operating height and diameter of the silicon core.

[0073] Combination Figure 4 and Figure 5 As shown, in some embodiments, the preheater 140 includes an external heater 141 and an internal heater 142. The external heater 141 is framed on the outside of the internal heater 142. A crucible 130 is disposed in the internal heater 142. Multiple crucibles 130 are disposed between the external heater 141 and the internal heater 142.

[0074] The outer heater 141 and the inner heater 142 can both be annular graphite heaters, the inner diameter of the outer heater 141 is larger than the outer side of the inner heater 142, and the centers of the two circles coincide. A crucible 130 is arranged at the center of the furnace body 110, and multiple crucibles 130 are evenly distributed around the crucible 130 located at the center, wherein the crucible 130 located at the center is arranged through the inner heater 142, and the other crucibles 130 are arranged between the outer heater 141 and the inner heater 142.

[0075] like Figure 4 As shown, in one embodiment, the number of the crucibles 130 is five, and four crucibles 130 are distributed around the crucible 130 located in the center.

[0076] like Figure 5 As shown, in one embodiment, the number of the crucibles 130 is nine, and eight crucibles 130 are distributed around the crucible 130 located in the center.

[0077] like Fig. 9 As shown, an embodiment of the present application further provides a silicon core production method, the silicon core production method comprising:

[0078] S10, preliminary preparation.

[0079] Clean the crucible 130. Clean all the crucibles 130, and clean the outer wall and the inner wall of the crucible 130 to prevent the impurities on the crucible 130 from contaminating the silicon core.

[0080] Apply silicon mud. Fine silicon powder is mixed with an appropriate amount of deionized water to form silicon mud, which is applied to the gap between two adjacent petals 131 of the crucible 130 and the inner wall surface of the crucible 130, and then dried in the shade or baked. This step can prevent the subsequent silicon material from contacting the inner wall of the crucible 130 after being heated and melted, thereby reducing the secondary contamination of the inner wall of the crucible 130 to the silicon melt.

[0081] In some embodiments, the purity of silicon powder may be 7-9N, and the thickness of silicon mud applied on the crucible 130 may be 1 mm-3 mm.

[0082] Sealing test: The crucibles 130 are pressure tested to detect whether there is any water leakage in all the crucibles 130. After confirming that there is no water leakage in the crucible 130, subsequent operations are performed to prevent the silicon material from leaking out after being heated and melted.

[0083] S20, preheating treatment.

[0084] Combined Figure 1As shown, the furnace chamber 112 environment is treated. The bottom of the crucible 130 is lowered to the heating zone of the preheater 140, and the induction heater 120 is raised. The rising distance of the induction heater 120 is at least greater than the height of the heating zone of the preheater 140. Polycrystalline silicon material with a particle size that meets the requirements is added to the crucible 130. At this time, the polycrystalline silicon material is located at the bottom of the crucible 130, and the filling height of the polycrystalline silicon material is greater than the heating zone of the heater by 10-200mm. Then, the furnace chamber 112 is evacuated. After the vacuum degree reaches the requirement, high-purity inert gas, such as argon, is filled into the vacuum furnace chamber 112 from the air inlet 113 at a certain flow rate, and the exhaust port 114 is opened.

[0085] The storage chamber 160 environment is treated. The feeding switch 180 is closed, and the cover 162 of the storage chamber 160 is opened. Polysilicon materials with particle sizes that meet the requirements are added to the storage chamber 160. The size of the storage chamber 160 and the weight of the materials added are designed according to the number of crucibles 130 and the required amount of materials added. Generally, the designed storage weight is 10-20% greater than the required weight. Then the cover 162 of the storage chamber 160 is closed, and the storage chamber 160 is evacuated from the exhaust port 163 to make the vacuum degree of the storage chamber 160 consistent with the vacuum degree of the main furnace chamber 112.

[0086] Preheating treatment: The inner heater 142 and the outer heater 141 are started to heat the bottom of the crucible 130, and the heating is stopped after the temperature of the polysilicon material rises to the set temperature.

[0087] In this embodiment, the set heating temperature of the polysilicon material is 750°C-850°C to meet the requirement that silicon has poor conductivity and its own temperature must reach above 700°C before induction heating can be performed.

[0088] S30, induction heating to generate a silicon core round rod.

[0089] Combined Figure 2 As shown, the position of the crucible 130 is adjusted. The crucible 130 is raised to above the upper edge of the heater, that is, the bottom of the crucible 130 is raised to be out of the heating zone of the heater, and at the same time, the induction heater 120 is lowered to the upper edge of the heater, so that the preheated part of the crucible 130 is inside the induction heater 120. At this time, the discharge pipe 170 below the storage chamber 160 also corresponds to the upper opening of the crucible 130 at the corresponding position.

[0090] Induction heating, directional solidification. Start the induction heater 120, and use the eddy current thermal effect generated by induction to melt the silicon material in the crucible 130. While heating, turn on the cooling water system, and the cooling water enters the cooling channel in the crucible 130 to cool the crucible 130. After all the existing polysilicon materials in the crucible 130 are melted, add polysilicon materials to the crucible 130 at a certain rate. The feeding method can be a point-to-point method. And the weight of the silicon material added per unit time should be less than the weight of the silicon material melted per unit time by the induction heater 120, so as to reduce the risk of the molten pool being extinguished due to the temperature drop after adding the cold silicon material, and the continuous directional solidification process being interrupted. In addition, while adding materials, the induction heater 120 is raised upward at a certain speed. As the induction heater 120 rises, the temperature of the silicon liquid in the crystallization zone below the crucible 130 gradually decreases. This part of the silicon liquid is in the lower part of the crucible 130 and cools down. The silicon core solidifies from the bottom of the crucible 130 to the top at a certain rate until the silicon core growth is completed. Furthermore, during the solidification process of the silicon core, impurity elements in the silicon liquid having a distribution coefficient less than 1 are expelled upward from the silicon liquid from the solid / liquid interface.

[0091] Take out the silicon rod and perform mechanical processing. After the silicon rod cools down, inflate the furnace chamber 112 to normal pressure, open the furnace door, and take out the silicon core round rod. Cut off the upper end section of the silicon rod enriched with impurities and the lower end section contacting the bottom of the crucible 130, and the remaining silicon rod part is the purified silicon core round rod obtained through directional solidification. Then, the surface of the purified silicon core round rod is polished, tapered, and punched to complete the mechanical processing of the silicon core round rod.

[0092] Cleaning and drying: The machined silicon core round rod is cleaned and dried to obtain the silicon core material required for industrial production.

[0093] In summary, the silicon core production equipment 100 and its production method provided by the present application, compared with the method of producing silicon core round rods by the direct pulling method and then cutting them into square silicon cores, do not require cutting, and can directly produce round silicon cores of different required diameters, and avoid damage to the silicon core during the cutting process and loss of silicon material during the cutting process. Compared with the direct pulling method for producing silicon core round rods, the preparation cost of the present application is lower and the energy consumption is lower. The equipment of the present application can produce multiple groups of silicon cores at the same time, with greater production capacity and higher efficiency.

[0094] The crucible 130 is initially heated by the preheater 140, and the heat is used to heat the basic silicon material. When the temperature of the basic silicon material rises to a conductive state, cooling water is supplied to the crucible 130, and the induction heater 120 is turned on. After that, the silicon material itself is inductively heated until it melts, solving the problem that silicon is not conductive at room temperature and cannot be directly heated by an electromagnetic field. At the same time, it also avoids the introduction of impurities such as carbon into the silicon raw material due to the use of other materials such as carbon in direct contact with the silicon raw material for heating.

[0095] Silicon mud is applied to the gap between two adjacent petals 131 of the crucible 130 and the inner wall surface of the crucible 130, and then dried in the shade or baked. This prevents the silicon melt from contacting the inner wall of the crucible 130, reduces the secondary contamination of the silicon melt by the wall of the crucible 130, and thus prepares a silicon core round rod with a low surface impurity content.

[0096] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0097] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A silicon core production device, characterized in that: include: At least one furnace body, the furnace body comprising a furnace wall, the furnace wall enclosing a furnace chamber; An induction heater, wherein the induction heater is installed in the furnace chamber, and one side of the induction heater is slidably connected to the furnace wall; at least one crucible, the induction heater is provided with a through hole, and the crucible passes through the through hole of the induction heater; A preheater, the preheater being distributed around the crucible; A lifter is provided corresponding to the crucible, and the end of each crucible is connected to one of the lifters.

2. The silicon core production equipment according to claim 1, characterized in that: The silicon core production equipment further comprises a material storage chamber, which is connected to an end of the furnace body away from the lifter.

3. The silicon core production equipment according to claim 2, characterized in that: A plurality of discharge pipes are arranged on one side of the storage chamber connected to the furnace body, each of the discharge pipes corresponds to one of the crucibles, and a feeding switch is arranged on the discharge pipe.

4. The silicon core production equipment according to claim 2, characterized in that: An air inlet is arranged at one end of the furnace body close to the material storage chamber, and an exhaust port is arranged at one side of the furnace body away from the material storage chamber.

5. The silicon core production equipment according to claim 1, characterized in that: The induction heater comprises a plurality of sub-induction heaters and a bracket, wherein the plurality of sub-induction heaters are mounted on the bracket, and one side of the bracket is connected to the furnace wall.

6. The silicon core production equipment according to claim 5, characterized in that: The furnace wall is provided with a lifting mechanism, and the lifting mechanism controls the lifting movement of the bracket in the furnace chamber.

7. The silicon core production equipment according to claim 5, characterized in that: A heat insulation plate is provided on one side of the induction heater close to the preheater.

8. The silicon core production equipment according to claim 1, characterized in that: The crucible comprises a plurality of petals, two adjacent petals are spliced ​​together, and cooling channels are arranged in the petals.

9. The silicon core production equipment according to claim 1, characterized in that: The preheater comprises an outer heater and an inner heater, the outer heater frame is arranged on the outer side of the inner heater, one crucible is arranged in the inner heater, and a plurality of crucibles are arranged between the outer heater and the inner heater.

10. The silicon core production equipment according to any one of claims 1 to 9, characterized in that: The silicon core production equipment comprises four furnace bodies, each of which is provided with a furnace door.

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