Device for preparing high-purity silicon from silicon ore and preparation method thereof

Abstract

The invention relates to a device for preparing high-purity silicon from silicon ore and a preparation method thereof, and belongs to the technical field of silicon ore processing. The device comprises a rack, a feeding unit, a screening unit, a crushing assembly, a loading assembly and a driving unit; the feeding unit is arranged in the rack; the screening unit is rotationally arranged in the rack and located below the feeding unit. The crushing assembly is arranged below the screening unit, and the output end of the screening unit is connected with the crushing assembly. The feeding assembly is arranged on the rack and communicates with the crushing assembly, and the output end of the feeding assembly is connected with the feeding unit. The driving unit is arranged on the rack and used for driving the screening unit, the crushing assembly and the feeding assembly to work. The rack comprises a shell, a base arranged at the lower end of the shell and a supporting frame arranged on the shell and connected with the feeding unit. Impurities in the silicon ore can be effectively removed, and the follow-up treatment difficulty of the silicon ore is improved.

Description

Technical Field

[0001] This invention relates to the field of silicon ore processing technology, and in particular to an apparatus and method for preparing high-purity silicon from silicon ore. Background Technology

[0002] High-purity silicon (purity ≥ 99.99%) is a core raw material for high-tech industries such as photovoltaics, semiconductors, and high-end optical glass. Its main raw material is silicon ore (with silicon dioxide as the main component). Currently, the process of preparing high-purity silicon from silicon ore mainly includes crushing, screening, purification, reduction, and refining. Among these, the screening process is a key prerequisite for removing impurities from silicon ore and improving the efficiency of subsequent purification.

[0003] In existing technologies, the screening of silicon ore mostly adopts a single physical screening (such as vibrating screening) or water flow screening. The connection between crushing and screening is loose, and there are the following technical defects: after the silicon ore is crushed, some impurities (such as heavy impurities such as iron and titanium oxides) are not completely separated from the silicon ore particles. Water flow screening can only remove loosely attached impurities and some coarse heavy impurities, but cannot separate impurities embedded in the silicon ore particles or those that are not completely separated. This results in a high load on subsequent purification processes and makes it difficult to improve the purity of high-purity silicon. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the background art by proposing an apparatus and method for preparing high-purity silicon from silicon ore that can effectively remove impurities from silicon ore and increase the difficulty of subsequent processing of silicon ore.

[0005] The technical solution of the present invention: an apparatus for preparing high-purity silicon from silicon ore, comprising, frame; The feeding unit is located inside the frame; The screening unit is rotatably mounted inside the frame and located below the feeding unit; A crushing component is disposed below the screening unit, and the output end of the screening unit is connected to the crushing component; A feeding assembly, mounted on the frame and connected to the crushing assembly, with its output end connected to the feeding unit; and A drive unit, mounted on the frame, is used to drive the screening unit, the crushing assembly, and the feeding assembly.

[0006] Preferably, the frame includes a housing, a base disposed at the lower end of the housing, and a support frame disposed on the housing and connected to the feeding unit.

[0007] Preferably, the feeding unit includes a feeding pipe disposed on the support frame, a sliding pipe slidably disposed on the feeding pipe, and an adjustment component disposed on the feeding pipe for driving the sliding pipe to move.

[0008] Preferably, the adjusting assembly includes a fixed plate disposed on the feed pipe, a guide rail disposed on the fixed plate, a threaded rod rotatably disposed on the fixed plate, and a plurality of connecting blocks disposed on the sliding pipe and slidably connected to the guide rail and threadedly connected to the threaded rod.

[0009] Preferably, the screening unit includes a screening cone rotatably disposed within the housing and located below the sliding tube, a diversion component disposed on the housing and slidably connected to the screening cone, a conveying pipe disposed below the diversion component and whose output end is connected to the crushing component, and a spiral receiving disc disposed on the housing and located below the screening cone; the screening cone is provided with a spiral groove, the opening size of which gradually increases from top to bottom.

[0010] Preferably, the crushing assembly includes a fixed frame disposed on the housing, a conical crushing table rotatably disposed within the fixed frame and having a conical structure with crushing grooves on its surface, and a connecting pipe disposed on the fixed frame and having its output end connected to the feeding assembly.

[0011] Preferably, the feeding assembly includes a feeding pipe disposed on the housing and communicating with the connecting pipe, a spiral conveying blade rotatably disposed in the feeding pipe, and a discharge pipe inclinedly disposed at the upper part of the feeding pipe and communicating with the feed pipe.

[0012] Preferably, the drive unit includes a drive motor mounted on the base, a belt drive assembly one mounted on the output end of the drive motor and connected to the spiral conveyor blade, a rotating column rotatably mounted on the base and connected to the screening cone and the conical crushing table, and a belt drive assembly two mounted on the belt drive assembly one and connected to the rotating column.

[0013] Preferably, the diversion assembly includes a flow guide frame disposed on the housing, a scraper disposed on the flow guide frame and slidably connected to the screening cone, and a plurality of diversion plates disposed on the flow guide frame and the scraper.

[0014] A method for preparing high-purity silicon from silicon ore includes the following steps: S1: Pretreatment, the silicon ore with SiO2 content ≥90% is washed with high-pressure water to remove loose impurities on the surface. The pressure of the high-pressure water is 0.3~0.5MPa. The washed silicon ore is initially crushed into coarse particles of 5~20mm to obtain pretreated silicon ore particles. S2: Feed adjustment and preliminary crushing: After mixing the pretreated silicon ore particles with water, they are fed into the feed pipe of the feed unit. The threaded rod of the adjustment component is rotated to drive the connecting block to slide along the guide rail, adjusting the gap between the sliding pipe and the screening cone of the screening unit. At the same time, the crushing blade connected to the rotating column of the drive unit is used to assist in crushing the larger silicon ore particles in the sliding pipe, ensuring that the particles can fall into the screening cone from the gap. S3: Primary water flow screening and classification. The drive unit drives the screening cone to rotate. Silica particles fall into the spiral grooves on the surface of the screening cone with the water flow. The opening size of the spiral grooves gradually increases from top to bottom to achieve silica particle size classification. The water flow carries away loose impurities on the surface of the silica particles and drops them into the spiral receiving tray for discharge. The scraper of the diversion component scrapes the silica particles off the screening cone. Fine particles <3mm are sent to the secondary water flow screening unit through the diversion plate, while coarse particles ≥3mm are sent to the crushing component 4. S4: Secondary crushing, the drive unit drives the cone crushing table of the crushing component to rotate, and squeezes, grinds and crushes the coarse silicon ore into fine particles of 0.074~3mm, which are then conveyed to the feeding component through the connecting pipe; S5: Circulating feeding. The drive unit drives the spiral conveyor blades of the feeding component to rotate, and feeds the crushed silicon ore particles back into the feed pipe through the discharge pipe. The cycle from S to S is repeated until all silicon ore particles are fine particles <3mm. S6: Secondary water flow screening. The <3mm fine silica particles obtained from steps S3 and S5 are fed into a hydraulic classification tank. The water flow rate is adjusted to 0.5~1m / s to prepare a slurry with a concentration of 20%~25%. The silica concentrate is separated from the fine heavy impurities by the difference in particle density. The middlings are refluxed and screened again by a reflux device to collect silica concentrate with SiO2 content ≥99.5% and Fe2O3 content ≤0.01%. S7: Purification. The silicon ore concentrate is fed into an acid washing tank, and a mixed acid solution with a hydrochloric acid concentration of 10%~20% and a hydrofluoric acid concentration of 1%~5% is added. The mixture is reacted at room temperature to 50℃ and a stirring speed of 30~60r / min for 0.5~2h. After acid washing, the concentrate is sent to a neutralization tank and ammonia water is added to adjust the pH to 6~7. After rinsing with deionized water 3~5 times, the concentrate is dehydrated to a water content of <20% using a dehydrator to obtain purified silicon ore concentrate with a SiO2 content of ≥99.95%. S8: Reduction. The purified silicon concentrate is mixed with a carbonaceous reducing agent with a carbon content ≥95% at a mass ratio of (2.8~3):(0.9~1.2):(0.1~0.3) and fed into a submerged arc furnace with a power of 6300~12500kVA in batches. The reaction is carried out at 1800~2200℃ for 3~4h for carbothermal reduction to generate liquid industrial silicon. After the reaction, the mixture is allowed to stand for 0.2~0.8h to remove the slag. S9: Refining. Liquid industrial silicon is fed into a refining furnace, and a slagging agent consisting of 40%~60% Na2CO3, 30%~55% SiO2, and 5%~25% NaF is added. The mass ratio of the slagging agent to the silicon concentrate is 2:(1~10). After refining, the silicon concentrate is fed into a directional solidification furnace. The furnace temperature is adjusted to 1450~1520℃, and a mixed gas with 98.5%~100% argon and 0~1.5% water vapor is introduced at a flow rate of 20~30 L / h. The cooling rate is controlled to cause trace impurities to accumulate at the tail of the silicon ingot. After cooling, the impurities at the tail are removed to obtain a high-purity silicon ingot with a purity ≥99.99%. Compared with the prior art, the present invention has the following beneficial technical effects: In this invention, ... Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a cross-sectional structural diagram of an embodiment of the present invention; Figure 3 This is a partial structural cross-sectional view of an embodiment of the present invention; Figure 4 for Figure 1 A magnified schematic diagram of the partial structure at point A in the middle; Figure 5 This is a partial structural diagram of an embodiment of the present invention; Figure 6 This is a schematic diagram of the sieving cone in this invention; Figure 7 This is a schematic diagram of the shunt component in this invention.

[0017] Reference numerals: 1. Frame; 101. Housing; 102. Base; 103. Support frame; 2. Feeding unit; 201. Feed pipe; 202. Adjusting component; 203. Sliding pipe; 2021. Fixed plate; 2022. Guide rail; 2023. Threaded rod; 2024. Connecting block; 3. Screening unit; 301. Screening cone; 302. Diverting component; 3021. Guide frame; 3022. Scraper; 3023. 303. Diverter plate; 304. Conveying pipe; 305. Spiral receiving plate; 306. Spiral groove; 4. Crushing assembly; 407. Fixed frame; 408. Conical crushing table; 409. Connecting pipe; 500. Feeding assembly; 501. Feeding pipe; 502. Spiral conveyor blade; 503. Discharge pipe; 6. Drive unit; 601. Drive motor; 602. Belt drive assembly one; 603. Belt drive assembly two; 604. Rotating column. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0020] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive, either alone or selectively, with other embodiments.

[0021] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0022] Example 1 like Figures 1-7 As shown, the present invention proposes an apparatus for preparing high-purity silicon from silicon ore, comprising a frame 1, a feeding unit 2, a screening unit 3, a crushing component 4, a feeding component 5, and a drive unit 6. A feeding unit 2 is disposed within the frame 1; a screening unit 3 is rotatably disposed within the frame 1 and located below the feeding unit 2; a crushing assembly 4 is disposed below the screening unit 3 and the output end of the screening unit 3 is connected to the crushing assembly 4; a feeding assembly 5 is disposed on the frame 1 and communicates with the crushing assembly 4, with its output end connected to the feeding unit 2; and a drive unit 6 is disposed on the frame 1 for driving the screening unit 3, the crushing assembly 4, and the feeding assembly 5. The frame 1 includes a housing 101, a base 102 disposed at the lower end of the housing 101, and a support frame 103 disposed on the housing 101 and connected to the feeding unit 2.

[0023] In this embodiment, a grading and screening crushing process is adopted, consisting of a feeding unit 2 for adjustment, a primary water flow screening unit 3, a secondary circulation crushing component 4, and a secondary water flow screening unit 7. The feeding unit 2, screening unit 3, crushing component 4, feeding component 5, and drive unit 6 are integrated into a single design. The two water flow screenings are adapted to the particle size of silicon ore after grading and screening and circulation crushing, respectively. The primary water flow screening unit 3 achieves silicon ore size grading and removal of loose impurities. The secondary circulation crushing component 4 ensures that impurities are completely separated from silicon ore particles. The secondary water flow screening unit 7 removes fine-grained heavy impurities and trace amounts of unseparated impurities, achieving impurity grading and deep removal. This solves the defects of incomplete impurity removal and large silicon ore loss in the prior art.

[0024] The feeding unit 2 adopts an adjustable structure. The sliding tube 203 is driven to move by the threaded rod 2023, which can flexibly adjust the feeding gap to match the screening requirements of silicon ore of different sizes. At the same time, the sliding tube 203 is equipped with a crushing blade 204, which can assist in crushing larger pieces of silicon ore, avoid material jamming, and ensure continuous operation of the equipment. The screening unit 3 adopts a screening cone 301 structure combined with a spiral groove 3011 design. The opening size of the spiral groove 3011 gradually increases from top to bottom, which can achieve precise classification of silicon ore. The scraper 3022 and the diversion plate 3023 of the diversion component 302 can accurately divert silicon ore of different sizes, improving screening efficiency and accuracy.

[0025] The system employs a circulating crushing component 4 and a feeding component 5 to re-crush the larger-sized silicon ore after screening by the screening unit 3 and recycle it into the feeding unit 2. This achieves a closed-loop process of "crushing-screening-re-crushing", ensuring that all silicon ore reaches the target particle size, impurities are completely separated from silicon ore particles, and silicon ore loss is significantly reduced, silicon ore recovery rate is improved, and resource utilization is increased.

[0026] Example 2 like Figures 1-7As shown, the present invention proposes an apparatus for preparing high-purity silicon from silicon ore. Compared with Embodiment 1, the feeding unit 2 in this embodiment includes a feeding pipe 201 disposed on the support frame 103, a sliding pipe 203 slidably disposed on the feeding pipe 201, and an adjustment component 202 disposed on the feeding pipe 201 for driving the sliding pipe 203 to move. The adjustment component 202 includes a fixed plate 2021 disposed on the feeding pipe 201, a guide rail 2022 disposed on the fixed plate 2021, a threaded rod 2023 rotatably disposed on the fixed plate 2021, and multiple connecting blocks 2024 disposed on the sliding pipe 203, slidably connected to the guide rail 2022, and threadedly connected to the threaded rod 2023.

[0027] In this embodiment, the silicon ore, after initial crushing, flows into the feed pipe 201 along with water. It then falls into the sliding pipe 203 through the feed pipe 201. The rotation of the threaded rod 2023 drives the connecting block 2024 to move, which in turn moves the sliding pipe 203. This adjusts the gap between the lower end of the sliding pipe 203 and the upper end of the screening cone 301, thereby controlling the size of the silicon ore falling onto the screening cone 301. The crushing blades located inside the sliding pipe 203 and mounted on the rotating column 604 can crush larger pieces of silicon ore, allowing them to fall through the gap between the sliding pipe 203 and the screening cone 301. Furthermore, the rotational crushing process prevents the silicon ore from getting stuck in the gap between the sliding pipe 203 and the screening cone 301.

[0028] Example 3 like Figures 1-7 As shown, the present invention proposes an apparatus for preparing high-purity silicon from silicon ore. Compared with Embodiment 1 or Embodiment 2, the screening unit 3 in this embodiment includes a screening cone 301 rotatably disposed within the housing 101 and located below the sliding tube 203, a diversion component 302 disposed on the housing 101 and slidably connected to the screening cone 301, a conveying pipe 303 disposed below the diversion component 302 and whose output end is connected to the crushing component 4, and a spiral receiving disc 304 disposed on the housing 101 and located below the screening cone 301. The screening cone 301 is provided with a spiral groove 3011, and the opening size of the spiral groove 3011 gradually increases from top to bottom. The diversion assembly 302 includes a flow guide frame 3021 disposed on the housing 101, a scraper 3022 disposed on the flow guide frame 3021 and slidably connected to the screening cone 301, and a plurality of diversion plates 3023 disposed on the flow guide frame 3021 and the scraper 3022.

[0029] The crushing assembly 4 includes a fixed frame 401 mounted on the housing 101, a conical crushing table 402 rotatably mounted inside the fixed frame 401 and having a conical structure with crushing grooves on its surface, and a connecting pipe 403 mounted on the fixed frame 401 and having its output end connected to the feeding assembly 5.

[0030] The feeding assembly 5 includes a feeding pipe 501 disposed on the housing 101 and connected to the connecting pipe 403, a spiral conveying blade 502 rotatably disposed in the feeding pipe 501, and a discharge pipe 503 inclinedly disposed on the upper part of the feeding pipe 501 and connected to the feed pipe 201.

[0031] The drive unit 6 includes a drive motor 601 mounted on the base 102, a belt drive assembly 602 mounted on the output end of the drive motor 601 and connected to the spiral conveyor blade 502, a rotating column 604 rotatably mounted on the base 102 and connected to the screening cone 301 and the conical crushing table 402, and a belt drive assembly 603 mounted on the belt drive assembly 602 and connected to the rotating column 604.

[0032] In this embodiment, the crushed silicon ore flows into the screening cone 301 along with the water flow. Since the silicon ore is of different sizes after crushing, with some larger and some smaller, the smaller silicon ore falls into the spiral groove 3011 above the screening cone 301, while the larger silicon ore falls into the spiral groove 3011 below the screening cone. This allows for screening based on the size of the silicon ore. At the same time, during screening, the water flow can carry away impurities attached to the silicon ore particles, as well as some substances with a mass smaller than the silicon ore, thereby removing impurities from the silicon ore.

[0033] Different sizes of silicon ore fall into screening cones 301 at different positions. The rotation of screening cones 301 drives the silicon ore to move, thus moving the silicon ore to the diversion component 302. The scraper 3022 scrapes the silicon ore off, so that the silicon ore at different positions falls onto the diversion plates 3023 at different positions, thereby screening silicon ore of different sizes. The screened silicon ore of different sizes is then transported to the fixed frame 401 through the corresponding conveying pipe 303. When the cone crushing table 402 rotates, it can crush the silicon ore. The crushed silicon ore falls into the fixed frame 401 and then into the feeding pipe 501 through the connecting pipe 403.

[0034] The drive motor 601 drives the belt drive assembly 602 to rotate, which in turn drives the screw conveyor blade 502 to rotate. The belt drive assembly 602, through the belt drive assembly 603, drives the rotating column 604 to rotate. When the screw conveyor blade 502 rotates, it can convey the silicon ore falling into the feed pipe 501 upwards. The rotating column 604 can drive the conical crushing table 402, the screening cone 301, and the crushing blade to rotate, thereby crushing and screening the silicon ore. Smaller silicon ore is discharged through the uppermost diversion plate 3023 and collected from there. The silicon ore collected here is less than 3mm in size, which can effectively remove impurities by physical means and avoid impurities affecting subsequent processing.

[0035] The impurities washed out by the water flow fall below the screening cone 301 and onto the spiral receiving plate 304, and are then discharged into the housing 101 through the diversion component 302, thus completely removing the impurities.

[0036] Example 4 like Figures 1-7 As shown, this invention proposes a method for preparing high-purity silicon from silicon ore, which includes the following steps: S1: Pretreatment, the silicon ore with SiO2 content ≥90% is washed with high-pressure water to remove loose impurities on the surface. The pressure of the high-pressure water is 0.3~0.5MPa. The washed silicon ore is initially crushed into coarse particles of 5~20mm to obtain pretreated silicon ore particles. S2: Feed adjustment and preliminary crushing. After the pre-treated silicon ore particles are mixed with water, they are fed into the feed pipe 201 of the feed unit 2. The threaded rod 2023 of the rotating adjustment component 202 drives the connecting block 2024 to slide along the guide rail 2022, adjusting the gap between the sliding pipe 203 and the screening cone 301 of the screening unit 3. At the same time, the crushing blade connected to the rotating column 604 of the drive unit 6 is used to assist in crushing the larger silicon ore particles in the sliding pipe 203, ensuring that the particles can fall into the screening cone 301 from the gap. S3: Primary water flow screening and grading. The drive unit 6 drives the screening cone 301 to rotate. Silica particles fall into the spiral groove 3011 on the surface of the screening cone 301 with the water flow. The opening size of the spiral groove 3011 gradually increases from top to bottom to achieve silica particle size grading. The water flow carries away loose impurities on the surface of the silica particles and drops them into the spiral receiving tray 304 for discharge. The scraper 3022 of the diversion component 302 scrapes the silica particles off the screening cone 301. Fine particles <3mm are sent to the secondary water flow screening unit through the diversion plate 3023, while coarse particles ≥3mm are sent to the crushing component 4. S4: Secondary crushing, the drive unit 6 drives the cone crushing table 402 of the crushing component 4 to rotate, and squeezes, grinds and crushes the coarse silicon ore to fine particles of 0.074~3mm, which are then conveyed to the feeding component 5 through the connecting pipe 403. S5: Circulating feeding. The drive unit 6 drives the spiral conveyor blade 502 of the feeding component 5 to rotate, and feeds the crushed silicon ore particles back into the feed pipe 201 through the discharge pipe 503. The cycle of steps S2 to S4 is repeated until all silicon ore particles are fine particles <3mm. S6: Secondary water flow screening. The <3mm fine silica particles obtained from steps S3 and S5 are fed into a hydraulic classification tank. The water flow rate is adjusted to 0.5~1m / s to prepare a slurry with a concentration of 20%~25%. The silica concentrate is separated from the fine heavy impurities by the difference in particle density. The middlings are refluxed and screened again by a reflux device to collect silica concentrate with SiO2 content ≥99.5% and Fe2O3 content ≤0.01%. S7: Purification. The silicon ore concentrate is fed into an acid washing tank, and a mixed acid solution with a hydrochloric acid concentration of 10%~20% and a hydrofluoric acid concentration of 1%~5% is added. The mixture is reacted at room temperature to 50℃ and a stirring speed of 30~60r / min for 0.5~2h. After acid washing, the concentrate is sent to a neutralization tank and ammonia water is added to adjust the pH to 6~7. After rinsing with deionized water 3~5 times, the concentrate is dehydrated to a water content of <20% using a dehydrator to obtain purified silicon ore concentrate with a SiO2 content of ≥99.95%. S8: Reduction. The purified silicon concentrate is mixed with a carbonaceous reducing agent with a carbon content ≥95% at a mass ratio of (2.8~3):(0.9~1.2):(0.1~0.3) and fed into a submerged arc furnace with a power of 6300~12500kVA in batches. The reaction is carried out at 1800~2200℃ for 3~4h for carbothermal reduction to generate liquid industrial silicon. After the reaction, the mixture is allowed to stand for 0.2~0.8h to remove the slag. S9: Refining. Liquid industrial silicon is fed into a refining furnace, and slagging agents of 40%~60% Na2CO3, 30%~55% SiO2, and 5%~25% NaF are added. The mass ratio of slagging agent to silicon concentrate is 2:(1~10). After refining, the silicon concentrate is fed into a directional solidification furnace. The furnace temperature is adjusted to 1450~1520℃, and a mixed gas of 98.5%~100% argon and 0~1.5% water vapor is introduced at a flow rate of 20~30L / h. The cooling rate is controlled to allow trace impurities to accumulate at the tail of the silicon ingot. After cooling, the impurities at the tail are removed to obtain a high-purity silicon ingot with a purity ≥99.99%.

[0037] In this embodiment, the silicon ore (SiO2 content ≥90%) is washed with high-pressure water (pressure 0.3~0.5MPa) through a pre-cleaning device to remove loose impurities such as surface clay, mud, sand, and plant residues; the washed silicon ore is then pre-crushed to coarse particles of 5~20mm to obtain pre-treated silicon ore particles, which are then fed into the feed pipe 201 of the feeding unit 2.

[0038] The drive motor 601 of the drive unit 6 is started. The drive motor 601 drives the rotating column 604 to rotate through the belt transmission assembly 1 602 and the belt transmission assembly 2 603, which in turn drives the crushing blades in the sliding tube 203 to rotate synchronously. According to the subsequent screening requirements, the threaded rod 2023 of the adjustment assembly 202 is rotated, which drives the connecting block 2024 to slide along the guide rail 2022, thereby adjusting the gap between the lower end of the sliding tube 203 and the upper end of the screening cone 301 to determine the maximum size of the silicon ore falling into the screening cone 301. The pre-treated silicon ore flows into the feed pipe 201 together with the water flow, and then falls into the sliding tube 203. The crushing blades in the sliding tube 203 assist in crushing larger pieces of silicon ore, so that their size can fall through the gap between the sliding tube 203 and the screening cone 301. At the same time, the rotational crushing prevents the silicon ore from getting stuck in the gap, ensuring smooth feeding.

[0039] The drive motor 601 drives the screening cone 301 to rotate synchronously. The silicon ore, after preliminary crushing, falls into the screening cone 301 along with the water flow from the gap between the sliding tube 203 and the screening cone 301. Since the silicon ore is of different sizes after crushing, smaller silicon ore (<3mm) falls into the spiral groove 3011 with a smaller opening at the top of the screening cone 301, while larger silicon ore (≥3mm) falls into the spiral groove 3011 with a larger opening at the bottom of the screening cone 301, thus achieving size classification of the silicon ore. At the same time, the water flows along the spiral groove 3011 during the rotation of the screening cone 301, which can carry away impurities such as clay, mud, and some substances smaller than silicon ore, such as organic impurities, attached to the silicon ore particles, thus achieving preliminary water flow impurity removal of the silicon ore. The impurities fall from the spiral groove 3011 with the water flow and fall into the spiral receiving plate 304 below, and are discharged from the shell 101 through the spiral receiving plate 304, completing the preliminary discharge of impurities.

[0040] During the rotation of the screening cone 301, the silicon ore is moved downward along the spiral groove 3011 to the diversion component 302. The scraper 3022 of the diversion component 302 slides against the surface of the screening cone 301, scraping the silicon ore from the spiral groove 3011 and guiding it to the diversion plates 3023 at different positions. Smaller silicon ore (<3mm) is discharged through the uppermost diversion plate 3023 and sent directly to the secondary water flow screening unit. Larger silicon ore (≥3mm) falls through the lower diversion plate 3023 into the corresponding conveying pipe 303 and is conveyed to the crushing component 4 for secondary crushing.

[0041] The drive motor 601 drives the conical crushing table 402 to rotate synchronously through the rotating column 604. The larger-sized silicon ore conveyed by the conveying pipe 303 falls onto the surface of the conical crushing table 402. During the rotation of the conical crushing table 402, the crushing grooves on its surface squeeze and grind the silicon ore, crushing it into fine particles of 0.074~3mm, ensuring that impurities that are not completely separated, such as fine iron and titanium oxide embedded in the silicon ore particles, are completely separated from the silicon ore particles. The crushed silicon ore falls into the fixed frame 401 and is conveyed to the feeding assembly 5 through the connecting pipe 403.

[0042] The drive motor 601 drives the spiral conveyor blade 502 to rotate via the belt drive assembly 602. When the spiral conveyor blade 502 rotates, it conveys the crushed silicon ore in the feed pipe 501 upwards and feeds it back into the feed pipe 201 through the inclined discharge pipe 503, entering the feed adjustment and preliminary crushing process of S2: to realize the "crushing-screening-re-crushing-re-screening" cycle until all silicon ore is crushed into fine particles <3mm, ensuring that impurities are completely separated from silicon ore particles, while improving the utilization rate of silicon ore and avoiding the waste of larger pieces of silicon ore.

[0043] Fine silica particles (<3mm in size) discharged from the top diversion plate 3023 in S3 (including fine particles finally screened after recycling crushing) are conveyed to the hydraulic classifier. The water flow velocity in the hydraulic classifier is adjusted (0.5~1m / s) to mix the fine silica particles with water to form a slurry (concentration 20%~25%). Utilizing the difference in settling velocity between particles of different densities, the silica concentrate is separated from the fine heavy impurities: silica concentrate (density 2.60~2.70g / cm³). 3 Slower settling velocity results in particles remaining in the upper layer of the hydraulic classifier, collected as silica concentrate; finer, heavier impurities (density ≥ 3.3 g / cm³) are collected. 3 The sediment settles quickly and settles at the bottom of the hydraulic classifier, where it is collected as fine-grained heavy impurity tailings. The middlings (mixed particles of silicon ore and impurities) generated at the bottom of the hydraulic classifier are returned to the secondary water flow screening unit for re-screening through a reflux device to improve the silicon ore recovery rate. At this time, the collected silicon ore concentrate has a SiO2 content ≥99.5% and an Fe2O3 content ≤0.01%.

[0044] The silicon concentrate obtained in S6 is fed into an acid washing tank, and a mixed acid solution of hydrochloric acid and hydrofluoric acid (hydrochloric acid concentration 10%~20%, hydrofluoric acid concentration 1%~5%) is added. The heating device of the acid washing tank is adjusted to room temperature~50℃, and the stirring speed of the stirring device is 30~60r / min. The reaction is carried out for 0.5~2h, so that the residual embedded fine metal oxides, carbonates and other impurities in the silicon concentrate react with the acid solution to generate soluble salts or volatile products. After acid washing, the material is sent to a neutralization tank, and ammonia water is added to adjust the pH to 6~7 to neutralize the residual acid solution. The neutralized material is sent to a water washing tank and repeatedly rinsed with deionized water 3~5 times to remove soluble salts and residual impurities. The water-washed material is sent to a dewatering machine (54) to dehydrate to a water content <20% to obtain purified silicon concentrate (SiO2 content ≥99.95%).

[0045] The purified silicon concentrate obtained in S7 is mixed with carbonaceous reducing agent (oil coke, charcoal, carbon content ≥95%) at a mass ratio of (2.8~3):(0.9~1.2):(0.1~0.3) and fed into the electric arc furnace (61) in batches through the feeding system. The power of the electric arc furnace (61) is adjusted to 6300~12500kVA and heated to 1800~2200℃ to carry out carbothermic reduction reaction. The reaction is carried out for 3~4 hours to generate liquid industrial silicon. The CO gas generated during the reduction process is collected, treated and recycled to avoid environmental pollution. After the reaction is completed, it is left to stand for 0.2~0.8 hours to remove the slag.

[0046] The liquid industrial silicon obtained from S8 is fed into a refining furnace, where a slagging agent (Na2CO3 40%~60%, SiO2 30%~55%, NaF 5%~25%) is added. The mass ratio of the slagging agent to the silicon concentrate is 2:(1~10) to further remove metallic impurities such as iron and aluminum from the industrial silicon. After refining, the liquid silicon is fed into a directional solidification furnace, and the temperature inside the furnace is adjusted to 1450~1520℃. A mixture of argon and water vapor (argon gas fraction 98.5%~100%, water vapor volume fraction 0~1.5%) is introduced at a flow rate of 20~30 L / h. The water cooling device is turned on (inlet water temperature 25℃, outlet water temperature 35~45℃, flow rate 10~15 m / h). 3 The cooling rate is controlled by a process called " / h" to allow residual trace impurities to accumulate at the tail of the silicon ingot. After directional solidification, the silicon ingot is cooled with the furnace to remove the tail where impurities have accumulated, resulting in a high-purity silicon ingot with a purity of ≥99.99%.

[0047] Furthermore, in S3 and S6, the heavy impurity tailings generated by water flow screening can be further recovered as valuable metals such as iron and titanium through magnetic separation, and the fine mud and sand can be used for building materials, realizing comprehensive resource utilization; in S7, the pickling waste liquid discharged from the pickling tank is neutralized to pH=6~9 in the neutralization tank (adding lime / sodium hydroxide), and after precipitation treatment, it is discharged in compliance with standards or recycled. The acid mist generated by pickling is treated by the acid mist absorption tower before being discharged, which meets environmental protection requirements.

[0048] Furthermore, in S4: the particle size of the secondary crushing can be adjusted according to the target high purity silicon purity. If it is necessary to prepare high purity silicon with higher purity (≥99.999%), the particle size of the secondary crushing can be adjusted to 0.074~2mm, while extending the number of cycles of crushing and the screening time of the secondary water flow screening unit to improve the impurity removal rate.

[0049] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. An apparatus for preparing high-purity silicon from silicon ore, characterized in that: include, Rack (1); The feeding unit (2) is disposed within the frame (1); The screening unit (3) is rotatably disposed within the frame (1) and located below the feeding unit (2); The crushing component (4) is disposed below the screening unit (3) and the output end of the screening unit (3) is connected to the crushing component (4); The feeding assembly (5) is mounted on the frame (1) and communicates with the crushing assembly (4), and its output end is connected to the feeding unit (2); as well as A drive unit (6) is mounted on the frame (1) to drive the screening unit (3), the crushing component (4) and the feeding component (5) to work.

2. The apparatus for preparing high-purity silicon from silicon ore according to claim 1, characterized in that, The frame (1) includes a housing (101), a base (102) disposed at the lower end of the housing (101), and a support frame (103) disposed on the housing (101) and connected to the feeding unit (2).

3. The apparatus for preparing high-purity silicon from silicon ore according to claim 2, characterized in that, The feeding unit (2) includes a feeding pipe (201) disposed on the support frame (103), a sliding pipe (203) slidably disposed on the feeding pipe (201), and an adjustment component (202) disposed on the feeding pipe (201) for driving the sliding pipe (203) to move.

4. The apparatus for preparing high-purity silicon from silicon ore according to claim 3, characterized in that, The adjustment assembly (202) includes a fixed plate (2021) disposed on the feed pipe (201), a guide rail (2022) disposed on the fixed plate (2021), a threaded rod (2023) rotatably disposed on the fixed plate (2021), and a plurality of connecting blocks (2024) disposed on the sliding pipe (203), which are slidably connected to the guide rail (2022) and threadedly connected to the threaded rod (2023).

5. The apparatus for preparing high-purity silicon from silicon ore according to claim 4, characterized in that, The screening unit (3) includes a screening cone (301) rotatably disposed inside the housing (101) and located below the sliding tube (203), a diversion component (302) disposed on the housing (101) and slidably connected to the screening cone (301), a conveying pipe (303) disposed below the diversion component (302) and whose output end is connected to the crushing component (4), and a spiral receiving disc (304) disposed on the housing (101) and located below the screening cone (301); the screening cone (301) is provided with a spiral groove (3011), and the opening size of the spiral groove (3011) gradually increases from top to bottom.

6. The apparatus for preparing high-purity silicon from silicon ore according to claim 5, characterized in that, The crushing assembly (4) includes a fixed frame (401) disposed on the housing (101), a conical crushing table (402) rotatably disposed in the fixed frame (401) and having a conical structure with a crushing groove on its surface, and a connecting pipe (403) disposed on the fixed frame (401) and having its output end facing the feeding assembly (5).

7. The apparatus for preparing high-purity silicon from silicon ore according to claim 6, characterized in that, The feeding assembly (5) includes a feeding pipe (501) disposed on the housing (101) and connected to the connecting pipe (403), a spiral conveying blade (502) rotatably disposed in the feeding pipe (501), and a discharge pipe (503) inclinedly disposed on the upper part of the feeding pipe (501) and connected to the feed pipe (201).

8. The apparatus for preparing high-purity silicon from silicon ore according to claim 7, characterized in that, The drive unit (6) includes a drive motor (601) mounted on the base (102), a belt drive assembly one (602) mounted on the output end of the drive motor (601) and connected to the spiral conveyor blade (502), a rotating column (604) rotatably mounted on the base (102) and connected to the screening cone (301) and the cone crushing table (402), and a belt drive assembly two (603) mounted on the belt drive assembly one (602) and connected to the rotating column (604).

9. The apparatus for preparing high-purity silicon from silicon ore according to claim 8, characterized in that, The diversion assembly (302) includes a flow guide frame (3021) disposed on the housing (101), a scraper (3022) disposed on the flow guide frame (3021) and slidably connected to the screening cone (301), and a plurality of diversion plates (3023) disposed on the flow guide frame (3021) and the scraper (3022).

10. A method for preparing high-purity silicon from silicon ore, based on the apparatus for preparing high-purity silicon from silicon ore according to claim 9, characterized in that, The method includes the following steps: S1: Pretreatment, the silicon ore with SiO2 content ≥90% is washed with high-pressure water to remove loose impurities on the surface. The pressure of the high-pressure water is 0.3~0.5MPa. The washed silicon ore is initially crushed into coarse particles of 5~20mm to obtain pretreated silicon ore particles. S2: Feed adjustment and preliminary crushing. After mixing the pretreated silicon ore particles with water, feed them into the feed pipe (201) of the feed unit (2). Rotate the threaded rod (2023) of the adjustment component (202) to drive the connecting block (2024) to slide along the guide rail (2022). Adjust the gap between the sliding tube (203) and the screening cone (301) of the screening unit (3). At the same time, use the crushing blade connected to the rotating column (604) of the drive unit (6) to assist in crushing the larger silicon ore particles in the sliding tube (203) to ensure that the particles can fall into the screening cone (301) from the gap. S3: Primary water flow screening and grading. The drive unit (6) drives the screening cone (301) to rotate. The silicon ore particles fall into the spiral groove (3011) on the surface of the screening cone (301) with the water flow. The opening size of the spiral groove (3011) gradually increases from top to bottom to realize the size grading of silicon ore particles. The water flow carries away the loose impurities on the surface of the silicon ore particles and falls into the spiral receiving plate (304) for discharge. The scraper (3022) of the diversion component (302) scrapes the silicon ore particles on the screening cone (301) off. The fine particles <3mm are sent to the secondary water flow screening unit through the diversion plate (3023), and the coarse particles ≥3mm are sent to the crushing component (4). S4: Secondary crushing, the drive unit (6) drives the cone crushing table (402) of the crushing component (4) to rotate, and squeezes, grinds and crushes the coarse silicon ore to fine particles of 0.074~3mm, which are then conveyed to the feeding component (5) through the connecting pipe (403). S5: Circulating feeding, the drive unit (6) drives the spiral conveyor blade (502) of the feeding component (5) to rotate, and feeds the crushed silicon ore particles back into the feed pipe (201) through the discharge pipe (503), and repeats steps S2 to S4 until all silicon ore particles are fine particles <3mm. S6: Secondary water flow screening. The <3mm fine silica particles obtained from steps S3 and S5 are fed into a hydraulic classification tank. The water flow rate is adjusted to 0.5~1m / s to prepare a slurry with a concentration of 20%~25%. The silica concentrate is separated from the fine heavy impurities by the difference in particle density. The middlings are refluxed and screened again by a reflux device to collect silica concentrate with SiO2 content ≥99.5% and Fe2O3 content ≤0.01%. S7: Purification. The silicon ore concentrate is fed into an acid washing tank, and a mixed acid solution with a hydrochloric acid concentration of 10%~20% and a hydrofluoric acid concentration of 1%~5% is added. The mixture is reacted at room temperature to 50℃ and a stirring speed of 30~60r / min for 0.5~2h. After acid washing, the concentrate is sent to a neutralization tank and ammonia water is added to adjust the pH to 6~7. After rinsing with deionized water 3~5 times, the concentrate is dehydrated to a water content of <20% using a dehydrator to obtain purified silicon ore concentrate with a SiO2 content of ≥99.95%. S8: Reduction. The purified silicon concentrate is mixed with a carbonaceous reducing agent with a carbon content ≥95% at a mass ratio of (2.8~3):(0.9~1.2):(0.1~0.3) and fed into a submerged arc furnace with a power of 6300~12500kVA in batches. The reaction is carried out at 1800~2200℃ for 3~4h for carbothermal reduction to generate liquid industrial silicon. After the reaction, the mixture is allowed to stand for 0.2~0.8h to remove the slag. S9: Refining. Liquid industrial silicon is fed into a refining furnace, and slagging agents of 40%~60% Na2CO3, 30%~55% SiO2, and 5%~25% NaF are added. The mass ratio of slagging agent to silicon concentrate is 2:(1~10). After refining, the silicon concentrate is fed into a directional solidification furnace. The furnace temperature is adjusted to 1450~1520℃, and a mixed gas of 98.5%~100% argon and 0~1.5% water vapor is introduced at a flow rate of 20~30L / h. The cooling rate is controlled to allow trace impurities to accumulate at the tail of the silicon ingot. After cooling, the impurities at the tail are removed to obtain a high-purity silicon ingot with a purity ≥99.99%.

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