A copper chloride catalyst recovery system

Abstract

The utility model provides a kind of copper chloride catalyst recovery system, the purpose is to solve the technical problems of cost increase and silicon powder waste caused by copper chloride catalyst loss in existing system.The system includes: synthetic furnace, hydrolysis unit, silicon residue processing unit and drying unit;Hydrolysis unit import is connected with synthetic furnace discharge outlet;Evaporation concentration unit inlet is connected with the clear liquid outlet of hydrolysis unit;Silicon residue processing unit import is connected with the discharge port of the bottom of hydrolysis unit;Drying unit import is connected with the crystallization outlet of evaporation concentration unit.The utility model is by being dissolved after stirring to hydrolysis unit by the waste silicon powder containing copper chloride, after static stratification, bottom silicon residue is recycled or sold after pressure filtration drying, and supernatant containing copper chloride is evaporated and concentrated under the protection of continuously passing hydrogen chloride gas, and then recycled after drying treatment, so that external procurement can be reduced, and production cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of polycrystalline silicon production technology, and in particular to a copper chloride catalyst recovery system. Background Technology

[0002] The current reaction principle of the cold hydrogenation process in the Siemens process for polysilicon is 3SICl4 + SI + 2H2 → 4SIHCl3. This reaction takes place in a fluidized bed reactor. Copper chloride is added as a catalyst to accelerate the reaction. The silicon powder used as the raw material has a purity of 99%. As the reaction continues, impurities gradually accumulate in the fluidized bed, leading to a gradual decrease in silicon powder purity and affecting conversion efficiency. To ensure conversion efficiency, low-purity silicon powder needs to be periodically removed from the bed. However, the copper chloride catalyst is also removed from the system along with the silicon powder, requiring continuous replenishment of copper chloride, increasing costs. The current method for treating the discharged copper chloride-containing silicon powder is to directly hydrolyze it in a hydrolysis tank, and all waste residue is then directly sent to wastewater treatment. This method has the following drawbacks: 1. The hydrolysis of copper chloride requires continuous replenishment of copper chloride to the system, resulting in significant cost increases; 2. The loss of silicon powder in the waste silicon powder also increases the cost of the SI raw material. Summary of the Invention

[0003] In view of the above situation and to overcome the defects of the prior art, the purpose of this utility model is to provide a copper chloride catalyst recovery system, which solves the technical problems of increased cost and waste of silicon powder caused by the loss of copper chloride catalyst in the existing system.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A copper chloride catalyst recovery system includes: a synthesis furnace; a hydrolysis unit, the inlet of which is connected to the slag outlet of the synthesis furnace; an evaporation and concentration unit, the inlet of which is connected to the clear liquid outlet of the hydrolysis unit; a silicon slag treatment unit, the inlet of which is connected to the slag outlet at the bottom of the hydrolysis unit; and a drying unit, the inlet of which is connected to the crystallization outlet of the evaporation and concentration unit.

[0006] This invention involves transporting copper chloride-containing waste silicon powder to a hydrolysis unit, adding demineralized water and stirring to dissolve it. After settling and stratifying, the bottom silicon slag is recycled or sold after pressure filtration and drying, generating certain economic benefits. The supernatant containing copper chloride is evaporated and concentrated under the protection of continuous hydrogen chloride gas, and then dried to obtain anhydrous copper chloride. Finally, the anhydrous copper chloride is returned to the cold hydrogenated fluidized bed for recycling, thereby reducing external procurement and lowering production costs.

[0007] Optionally, the evaporation and concentration unit is connected to a hydrogen chloride pipeline for introducing hydrogen chloride. During the evaporation process, continuous introduction of hydrogen chloride provides protection, preventing copper chloride from combining with water to form copper hydroxide, thus losing its catalytic activity and ultimately forming copper chloride containing bound water.

[0008] Optionally, the discharge end of the drying unit is connected to a product pipeline. This pipeline can be used to transport the product copper chloride to the synthesis furnace. By recycling the final anhydrous copper chloride, it is beneficial to reduce external procurement and lower costs.

[0009] Optionally, the hydrolysis unit includes: a hydrolysis tank, the top inlet of which is connected to the slag outlet of the synthesis furnace via a first pipeline, the clear liquid outlet on the side wall of which is connected to the liquid inlet of the evaporation and concentration unit via a second pipeline, and the slag outlet at the bottom of which is connected to the inlet of the silicon slag treatment unit via a third pipeline; and a stirring device disposed inside the hydrolysis tank.

[0010] Optionally, the upper end of the hydrolysis tank is connected to a fourth pipeline for discharging waste gas to the waste gas treatment system.

[0011] Optionally, a sixth pipeline connects the evaporation and concentration unit to the fourth pipeline.

[0012] Optionally, the evaporation and concentration unit is connected to a seventh pipeline for steam inlet and an eighth pipeline for condensate outlet.

[0013] Optionally, the silica slag treatment unit includes: a filter press, the inlet of which is connected to the slag discharge port at the bottom of the hydrolysis tank via a third pipeline; and a drying device, the inlet of which is connected to the outlet of the filter press.

[0014] Optionally, a ninth pipeline connects the drying unit and the evaporation and concentration unit. One end of the ninth pipeline is connected to the inlet of the drying unit, and the other end is connected to the bottom of the evaporation and concentration unit through multiple first branch pipes.

[0015] Optionally, the drying unit includes: a vibrating fluidized bed; a hot air intake system, including a hot air duct connected to the vibrating fluidized bed, a heat exchanger and a hot air blower connected to the hot air duct, and a steam inlet pipe and a steam outlet pipe connected to the heat exchanger; and a cold air intake system, including a cold air duct connected to the vibrating fluidized bed.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] This invention involves feeding copper chloride-containing waste silicon powder into a hydrolysis unit, adding demineralized water, stirring to dissolve it, and allowing it to settle and separate into layers. The bottom silicon slag is then filtered, dried, and recycled or sold, generating certain economic benefits. The supernatant containing copper chloride is evaporated and concentrated under the protection of continuous hydrogen chloride gas, and then dried to obtain anhydrous copper chloride. Finally, the anhydrous copper chloride is returned to the cold hydrogenation fluidized bed for recycling, thereby reducing external procurement and lowering production costs. Simultaneously, the continuous introduction of hydrogen chloride during the evaporation process prevents copper chloride from combining with water to form copper hydroxide, thus losing its catalytic activity and ultimately forming copper chloride containing bound water. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Reference numerals: 1. Synthesis furnace; 2. Hydrolysis unit; 3. Evaporation and concentration unit; 4. Silica slag treatment unit; 5. Drying unit; 51. Vibrating fluidized bed; 52. Hot air pipeline; 521. Second branch pipe; 53. Heat exchanger; 54. Cold air pipeline; 10. Hydrogen chloride pipeline; 11. First pipeline; 12. Second pipeline; 13. Third pipeline; 14. Fourth pipeline; 15. Fifth pipeline; 16. Sixth pipeline; 17. Seventh pipeline; 18. Eighth pipeline; 19. Ninth pipeline; 191. First branch pipe; 20. Product pipeline. Detailed Implementation

[0021] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of this utility model application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0022] In the description of the embodiments of this utility model application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", "end", "side" etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, are only for the convenience of describing the embodiments of this utility model application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of this utility model application.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this utility model application, "multiple" means two or more, unless otherwise explicitly specified.

[0024] In the embodiments of this utility model application, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model application according to the specific circumstances.

[0025] In the embodiments of this utility model application, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0026] The following disclosure provides many different implementations or examples for carrying out different structures of the embodiments of this utility model application. To simplify the disclosure of the embodiments of this utility model application, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the embodiments of this utility model application. Furthermore, reference numerals and / or reference letters may be repeated in different examples of the embodiments of this utility model application; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0027] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0028] like Figure 1 As shown in the figure, the present invention provides a copper chloride catalyst recovery system, including: a synthesis furnace 1, a hydrolysis unit 2, an evaporation and concentration unit 3, and a silicon slag treatment unit 4.

[0029] Synthesis furnace 1 is used to generate waste silicon powder containing copper chloride. The inlet of hydrolysis unit 2 is connected to the slag outlet of synthesis furnace 1. The liquid inlet of evaporation and concentration unit 3 is connected to the clear liquid outlet of hydrolysis unit 2. The inlet of silicon slag treatment unit 4 is connected to the slag outlet at the bottom of hydrolysis unit 2.

[0030] During use, the waste silicon powder containing about 5% copper chloride discharged from the synthesis furnace 1 enters the hydrolysis unit 2. The copper chloride is hydrolyzed in the hydrolysis unit 2. The upper clear liquid and the bottom silicon slag are separated by static separation. The bottom silicon slag is filtered and dried by the silicon slag treatment unit 4. This part of the waste slag containing silicon powder can be recycled or sold. The upper clear liquid is a chloride containing a large amount of copper chloride and a small amount of other metal impurities. The clear liquid is evaporated and concentrated by the evaporation and concentration unit 3.

[0031] In one embodiment, the copper chloride catalyst recovery system further includes a drying unit 5, the inlet of which is connected to the crystal outlet of the evaporation and concentration unit 3. The copper chloride containing bound water obtained from the evaporation and concentration unit 3 enters the drying unit 5 for drying treatment to obtain anhydrous copper chloride. The final anhydrous copper chloride can be recycled to reduce external procurement.

[0032] In one embodiment, the evaporation and concentration unit 3 is connected to a hydrogen chloride pipeline 10 for introducing hydrogen chloride. After the copper chloride enters the evaporation and concentration unit 3, during the evaporation process, the continuous introduction of hydrogen chloride provides protection, preventing copper chloride from combining with water to form copper hydroxide, thereby losing its catalytic activity and ultimately forming copper chloride containing bound water.

[0033] Furthermore, the hydrolysis unit 2 includes a hydrolysis tank and a stirring device installed inside the hydrolysis tank. The top inlet of the hydrolysis tank is connected to the slag outlet of the synthesis furnace 1 through a first pipeline 11. The clear liquid outlet on the side wall of the hydrolysis tank is connected to the liquid inlet of the evaporation and concentration unit 3 through a second pipeline 12. The slag outlet at the bottom of the hydrolysis tank is connected to the inlet of the silicon slag treatment unit 4 through a third pipeline 13.

[0034] Optionally, the upper end of the hydrolysis tank is connected to a fourth pipeline 14 for discharging waste gas to the waste gas treatment system.

[0035] Optionally, the silicon slag treatment unit 4 is provided with a silicon slag discharge outlet at the bottom and a fifth pipeline 15 for discharging wastewater to the sewage treatment system is connected to one side.

[0036] In this implementation scenario, the silica slag treatment unit 4 includes a filter press and a drying device. The feed inlet of the filter press is connected to the slag discharge port at the bottom of the hydrolysis tank via a third pipeline 13, and the inlet of the drying device is connected to the outlet of the filter press.

[0037] Optionally, a sixth pipe 16 is connected between the evaporation and concentration unit 3 and the fourth pipe 14. The waste gas in the evaporation and concentration unit 3 enters the fourth pipe 14 through the sixth pipe 16 for merging and then enters the waste gas treatment system.

[0038] Optionally, the evaporation and concentration unit 3 is connected to a seventh pipe 17 for steam inlet and an eighth pipe 18 for condensate outlet.

[0039] Optionally, the inlet of the drying unit 5 is connected to the bottom of the evaporation and concentration unit 3 via the ninth pipe 19.

[0040] Optionally, one end of the ninth pipe 19 has multiple first branch pipes 191. One end of the ninth pipe 19 is connected to the inlet of the drying unit 5, and the other end is connected to multiple first branch pipes 191. The other end of the first branch pipes 191 is connected to the bottom of the evaporation and concentration unit 3. Optionally, there are three first branch pipes 191, which are distributed at both ends and the middle of the evaporation and concentration unit 3, respectively.

[0041] Optionally, the discharge end of the drying unit 5 is connected to a product pipeline 20. In use, the product pipeline 20 can be used to transport the dried copper chloride product to a synthesis furnace / fluidized bed for recycling.

[0042] As a method for recovering copper chloride catalyst: First, waste silicon powder containing approximately 5% copper chloride, discharged from the synthesis of trichlorosilane, enters hydrolysis unit 2. Copper chloride has a solubility of 745 g / L in water. It is first hydrolyzed with demineralized water, and continuously stirred by a stirring device during hydrolysis to ensure that most of the copper chloride in the waste silicon powder dissolves in the water. Then, the upper clear liquid and the lower silicon slag are separated by settling. The lower silicon slag enters silicon slag treatment unit 4 through third pipeline 13, is pressure filtered and dried, and then discharged from the bottom (this waste slag containing silicon powder can be recycled or sold). The upper clear liquid enters evaporation and concentration unit 3 through second pipeline 12 for evaporation and concentration. During evaporation, hydrogen chloride is continuously introduced for protection. The waste gas is discharged to the waste gas treatment system through fourth pipeline 14 for treatment. Evaporation and concentration unit 3 ultimately forms copper chloride containing bound water, which enters drying unit 5 through ninth pipeline 19 for drying to obtain anhydrous copper chloride. The final anhydrous copper chloride can be recycled to reduce external procurement. In actual use, control valves are installed on each pipeline for intelligent regulation.

[0043] In one embodiment, the drying unit 5 includes a vibrating fluidized bed 51 and a hot air intake system and a cold air intake system connected and communicating with the vibrating fluidized bed 51.

[0044] Optionally, the hot air intake system includes a hot air duct 52, on which a heat exchanger 53 and a hot air blower are connected. A steam inlet pipe and a steam outlet pipe are connected to the heat exchanger. One end of the hot air duct 52 is connected to the bottom of the vibrating fluidized bed 51 via multiple second branch pipes 521. In use, live steam is introduced into the heat exchanger 53 through the steam inlet pipe and discharged from the steam outlet pipe after heat exchange. Under the action of the hot air blower, ambient temperature air is heated by the heat exchanger 53 and then enters the vibrating fluidized bed 51.

[0045] Optionally, the cold air intake system includes a cold air duct 54, which is connected to one side of the second branch pipe 521 at the end. For example, the outlet of the vibrating fluidized bed 51 is located at the right end, and multiple second branch pipes 521 are arranged sequentially from left to right. The cold air duct 54 is located between the right-side second branch pipe and the outlet of the vibrating fluidized bed 51. In use, under the action of the cold air fan, cold air enters the vibrating fluidized bed 51 through the cold air duct 54. The dual-path intake of hot and cold air and steam heat exchange are beneficial to improving the drying efficiency of silicon slag particles.

[0046] In this system, waste silicon powder is not hydrolyzed in the slurry system, but instead undergoes a completely new process for recycling. Specifically, after hydrolysis in the hydrolysis unit, the bottom silicon slag is allowed to settle and separate into layers. After pressure filtration and drying, it is either recycled or sold (generating certain economic benefits). The supernatant containing copper chloride is evaporated and concentrated under the protection of continuous hydrogen chloride gas, and then dried to obtain anhydrous copper chloride. Finally, the anhydrous copper chloride is returned to the cold hydrogenated fluidized bed for recycling, thereby reducing external procurement and lowering production costs.

[0047] A method of using a copper chloride catalyst recovery system includes the following steps:

[0048] Step S1 involves conveying the copper chloride-containing waste silicon powder discharged from synthesis furnace 1 to hydrolysis unit 2, where demineralized water is added and stirred to dissolve it. This step may specifically include the following process:

[0049] Step S11: The waste silicon powder containing about 5% copper chloride discharged from the cold hydrogenated fluidized bed is transported to the hydrolysis unit 2.

[0050] Step S12: Add demineralized water;

[0051] Step S13: Dissolve the material by continuous stirring using a stirring device.

[0052] Step S2: Allow to stand and separate into layers;

[0053] Step S3: After settling and stratification, the bottom silica slag is recovered after pressure filtration and drying, and the supernatant containing copper chloride is evaporated and concentrated under the protection of continuous hydrogen chloride gas.

[0054] In step S4, the concentrate is vacuum dried to obtain anhydrous copper chloride powder, which is then returned to the cold hydrogenated fluidized bed for recycling.

[0055] In one embodiment, the solubility of copper chloride in water is 745 g / L.

[0056] In one embodiment, the temperature of the added demineralized water is 20-30°C, and the standing time is 2 hours.

[0057] In one embodiment, in step S3, after settling and stratification, the supernatant containing copper chloride is extracted from the middle of the hydrolysis unit 2 and transferred to the evaporation and concentration unit 3. Hydrogen chloride gas is continuously introduced into the evaporation and concentration unit 3 for concentration under the protection of hydrogen chloride gas.

[0058] Any aspects not described in detail in this embodiment are techniques known in the art.

[0059] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this utility model, and these should all be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A copper chloride catalyst recovery system characterized by, include: Synthesis furnace (1); The hydrolysis unit (2) has its inlet connected to the slag outlet of the synthesis furnace (1); The evaporation and concentration unit (3) has its inlet connected to the clear liquid outlet of the hydrolysis unit (2); The inlet of the silicon slag treatment unit (4) is connected to the slag discharge port at the bottom of the hydrolysis unit (2); The drying unit (5) has its inlet connected to the crystal outlet of the evaporation and concentration unit (3).

2. The copper chloride catalyst recovery system of claim 1, wherein, The evaporation and concentration unit (3) is connected to a hydrogen chloride pipeline (10) for introducing hydrogen chloride.

3. The copper chloride catalyst recovery system according to claim 1 or 2, characterized in that, The discharge end of the drying unit (5) is connected to a product pipeline (20).

4. The copper chloride catalyst recovery system according to claim 1 or 2, characterized in that, The hydrolysis unit (2) includes: The hydrolysis tank has its top inlet connected to the slag outlet of the synthesis furnace (1) via a first pipeline (11), its side wall clear liquid outlet connected to the liquid inlet of the evaporation and concentration unit (3) via a second pipeline (12), and its bottom slag outlet connected to the inlet of the silicon slag treatment unit (4) via a third pipeline (13). A stirring device is installed inside the hydrolysis tank.

5. The copper chloride catalyst recovery system according to claim 4, characterized in that, The upper end of the hydrolysis tank is connected to a fourth pipeline (14) for discharging waste gas to the waste gas treatment system.

6. The copper chloride catalyst recovery system according to claim 5, characterized in that, A sixth pipeline (16) is connected between the evaporation and concentration unit (3) and the fourth pipeline (14).

7. The copper chloride catalyst recovery system of claim 1 or 2, wherein, The evaporation and concentration unit (3) is connected to a seventh pipeline (17) for steam entry and an eighth pipeline (18) for condensate discharge.

8. The copper chloride catalyst recovery system according to claim 1 or 2, characterized in that, The silicon slag treatment unit (4) includes: The filter press has its feed inlet connected to the slag discharge port at the bottom of the hydrolysis unit (2) via a third pipeline (13); The drying device has its inlet connected to the outlet of the filter press.

9. The copper chloride catalyst recovery system of claim 1 or 2, wherein, A ninth pipeline (19) is connected between the drying unit (5) and the evaporation and concentration unit (3). One end of the ninth pipeline (19) is connected to the inlet of the drying unit (5), and the other end is connected to the bottom of the evaporation and concentration unit (3) through multiple first branch pipes (181).

10. The copper chloride catalyst recovery system according to claim 1 or 2, characterized in that, The drying unit (5) includes: Vibrating fluidized bed (51); The hot air intake system includes a hot air duct (52) connected to the vibrating fluidized bed (51), a heat exchanger (53) and a hot air blower are connected to the hot air duct (52), and a steam inlet pipe and a steam outlet pipe are connected to the heat exchanger (53). The cold air intake system includes a cold air duct (54) connected to the vibrating fluidized bed (51).

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