Preparation method of polycrystalline silicon catalyst for new energy

Abstract

The invention relates to the technical field of polycrystalline silicon system catalysts, in particular to a preparation method of a polycrystalline silicon catalyst for new energy, which comprises the following steps: preparing mesoporous polystyrene microspheres; the preparation method comprises the following steps: dispersing mesoporous polystyrene microspheres in a metal salt solution for precipitation reaction, dispersing the obtained supported polystyrene microspheres in ethanol, then adding stronger ammonia water and tetraethyl orthosilicate for stirring reaction to obtain supported silicon dioxide microspheres; and calcining in a carbon monoxide atmosphere to prepare the polycrystalline silicon system catalyst. According to the preparation method, loading and precipitation of metal salt are carried out by dissolving a large number of mesopores in polystyrene microspheres, then the polystyrene microspheres loaded with metal precipitation particles are fixed by a sol-gel method, and the interior and the surface of the generated silicon dioxide microspheres are mingled with the loaded polystyrene microspheres; and high-temperature reduction calcination is carried out in the atmosphere of carbon monoxide, so that the prepared polycrystalline silicon system catalyst has relatively high tetrachlorosilane conversion rate and long-time use stability.

Description

Technical Field

[0001] The present invention relates to the technical field of polysilicon system catalysts, and specifically to a preparation method of a polysilicon catalyst for new energy. Background Art

[0002] Photovoltaic power generation requires the use of polysilicon photovoltaic panels. The rapid development of the photovoltaic industry has driven the rapid expansion of polysilicon production capacity. The current mainstream improved Siemens process for producing polysilicon will produce a large amount of by-product trichlorosilane. Due to the enrichment of impurities and polymers, the cost of separation and purification is relatively high, and it is difficult to effectively recycle; at the same time, due to the strong corrosiveness, volatility, toxicity and harmfulness of trichlorosilane, the safety risk and environmental hazard are relatively large, which greatly increases the safety disposal cost of polysilicon enterprises. How to effectively solve the problem of treating the by-product trichlorosilane of polysilicon is of great significance for the green and sustainable development of the polysilicon industry.

[0003] At present, trichlorosilane is converted through the cold hydrogenation process to obtain trichlorosilane, the raw material for producing polysilicon, which can be recycled back to the production system for use. The cold hydrogenation process is to introduce a catalyst, add trichlorosilane, hydrogen, silicon powder and the catalyst into a fluidized bed or a fixed bed for reaction, which can achieve higher reaction efficiency and reduce energy consumption. Among them, the introduced catalyst will have the problem of loss of active components during the catalytic reaction process, affecting the catalytic conversion of trichlorosilane. Based on this, a preparation method of a polysilicon catalyst for new energy is proposed. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a preparation method of a polysilicon catalyst for new energy. By fixing polystyrene microspheres loaded with metal precipitate particles through the sol-gel method and performing high-temperature reduction calcination in an atmosphere of carbon monoxide, the prepared polysilicon system catalyst has a high conversion rate of trichlorosilane and good use stability.

[0005] To achieve the above object, the present invention provides the following technical solutions: A preparation method of a polysilicon catalyst for new energy, comprising the following steps,

[0006] (1) Sulfonate and etch polystyrene microspheres in sequence to obtain mesoporous polystyrene microspheres;

[0007] (2) Ultrasonically disperse the mesoporous polystyrene microspheres in a metal salt solution, then add a precipitant solution to adjust the pH to 8-10. After the precipitation reaction ends, separate, wash and dry to obtain supported polystyrene microspheres;

[0008] (3) Disperse the supported polystyrene microspheres in a 75wt% ethanol solution, then add concentrated ammonia water and tetraethyl orthosilicate, and continuously stir and react. After separation, washing, drying and grinding, supported silica microspheres are obtained;

[0009] (4) Place the supported silica microspheres in a muffle furnace and calcine them under a carbon monoxide atmosphere to obtain a polysilicon system catalyst.

[0010] Preferably, in step (1), the sulfonation treatment is specifically as follows: Mix polystyrene microspheres and concentrated sulfuric acid at a material-liquid ratio of 1:30 g / mL, react at 40 - 45 °C for 15 - 18 h, and obtain sulfonated polystyrene microspheres through separation, washing, and drying.

[0011] Preferably, in step (1), the etching treatment is specifically as follows: Uniformly disperse the sulfonated polystyrene microspheres in deionized water, then add n-heptane, react at 65 - 70 °C for 2 - 2.5 h, and obtain mesoporous polystyrene microspheres through separation, washing, and drying.

[0012] Preferably, the volume ratio of n-heptane to deionized water is (1 - 3):10; the material-liquid ratio of sulfonated polystyrene microspheres to deionized water is 5:1.

[0013] Preferably, in step (2), the metal salt solution is selected from 5 wt% copper chloride solution and 5 wt% cobalt chloride solution; the precipitating agent is selected from 10 wt% sodium carbonate solution.

[0014] Preferably, in step (2), the mass ratio of the mesoporous polystyrene microspheres to the metal salt solution is 1:(8 - 10).

[0015] Preferably, in step (3), the concentration of the supported polystyrene microspheres in the supported polystyrene microsphere alcohol solution formed with 75 wt% ethanol solution is 0.2 mg / mL; the volume ratio of the supported polystyrene microsphere alcohol solution, concentrated ammonia water, and tetraethyl orthosilicate is 100:2:1; continuously stir and react for 2 - 3 h.

[0016] Preferably, in step (4), the calcination treatment temperature is 550 - 600 °C, and the calcination treatment time is 1.5 - 2 h.

[0017] The present invention provides a preparation method of a polysilicon catalyst for new energy, which has the following beneficial effects compared with the prior art:

[0018] In the present invention, a large number of mesopores are etched on the polystyrene microspheres, metal salts are loaded and precipitated, and then the polystyrene microspheres loaded with metal precipitation particles are fixed by the sol-gel method. The generated silica microspheres are internally and on the surface mixed with supported polystyrene microspheres. High-temperature reduction calcination is carried out under a carbon monoxide atmosphere, and the obtained polysilicon system catalyst has a high conversion rate of tetrachlorosilane and long-term use stability.

[0019] In the present invention, n - heptane, a poor solvent, is used to corrode sulfonated polystyrene microspheres. While not damaging the original spherical structure of the microspheres, mesopores can be generated on them, which is beneficial to the sufficient loading and precipitation of metal salts to improve the catalytic effect of the catalyst.

[0020] In the present invention, the supported silica microspheres are calcined in a carbon monoxide atmosphere. Carbon monoxide reduces the metal precipitate to metallic copper / cobalt. At the same time, the polystyrene microspheres decompose during calcination, and the generated gases escape, forming voids inside and on the surface of the silica microspheres, directly exposing part of the copper / cobalt, ensuring that the catalytically active sites can directly contact the materials, thereby improving the catalytic effect and contributing to the catalytic conversion of silicon tetrachloride. Detailed implementation mode

[0021] The following examples are used to illustrate in detail the implementation mode of the present application, so as to fully understand how the present application uses technical means to solve technical problems and achieve the realization process of technical effects and implement accordingly.

[0022] Example 1

[0023] The preparation method of sulfonated polystyrene microspheres is as follows:

[0024] The polystyrene microspheres and concentrated sulfuric acid are mixed according to the material - liquid ratio of 1:30 g / mL and reacted at 40 °C for 18 h. After separation, washing and drying, sulfonated polystyrene microspheres are obtained.

[0025] Example 2

[0026] The preparation method of sulfonated polystyrene microspheres is as follows:

[0027] The polystyrene microspheres and concentrated sulfuric acid are mixed according to the material - liquid ratio of 1:30 g / mL and reacted at 45 °C for 15 h. After separation, washing and drying, sulfonated polystyrene microspheres are obtained.

[0028] Example 3

[0029] The preparation method of mesoporous polystyrene microspheres is as follows:

[0030] The sulfonated polystyrene microspheres (prepared in Example 1) are uniformly dispersed in deionized water, and then n - heptane is added. The reaction is carried out at 65 °C for 2.5 h. After separation, washing and drying, mesoporous polystyrene microspheres are obtained.

[0031] The volume ratio of the above - mentioned n - heptane to deionized water is 1:10; the material - liquid ratio of the sulfonated polystyrene microspheres (prepared in Example 1) to deionized water is 5:1.

[0032] Example 4

[0033] The preparation method of mesoporous polystyrene microspheres is as follows:

[0034] The sulfonated polystyrene microspheres (prepared in Example 2) were uniformly dispersed in deionized water, then n - heptane was added, and the reaction was carried out at 70 °C for 2 h. After separation, washing and drying, mesoporous polystyrene microspheres were obtained.

[0035] The volume ratio of the above - mentioned n - heptane to deionized water was 3:10; the ratio of the sulfonated polystyrene microspheres (prepared in Example 2) to deionized water in the feed liquid was 5:1.

[0036] Example 5

[0037] A preparation method of a polysilicon catalyst for new energy, comprising the following steps:

[0038] (1) The mesoporous polystyrene microspheres (prepared in Example 3) were ultrasonically dispersed in a 5 wt% copper chloride solution, then a 10 wt% sodium carbonate solution was added to adjust the pH to 8. After the precipitation reaction ended, separation, washing and drying were carried out to obtain supported polystyrene microspheres;

[0039] The mass ratio of the above - mentioned mesoporous polystyrene microspheres (prepared in Example 3) to the 5 wt% copper chloride solution was 1:8.

[0040] (2) The supported polystyrene microspheres were dispersed in a 75 wt% ethanol solution to obtain a 0.2 mg / mL supported polystyrene microsphere ethanol solution. Then concentrated ammonia water and tetraethyl orthosilicate were added, and the reaction was continuously stirred for 2 h. After separation, washing, drying and grinding, supported silica microspheres were obtained;

[0041] The volume ratio of the above - mentioned supported polystyrene microsphere ethanol solution, concentrated ammonia water and tetraethyl orthosilicate was 100:2:1.

[0042] (3) The supported silica microspheres were placed in a muffle furnace and calcined at 600 °C for 1.5 h under a carbon monoxide atmosphere to obtain a polysilicon system catalyst.

[0043] Example 6

[0044] A preparation method of a polysilicon catalyst for new energy, comprising the following steps:

[0045] (1) The mesoporous polystyrene microspheres (prepared in Example 4) were ultrasonically dispersed in a 5 wt% cobalt chloride solution, then a 10 wt% sodium carbonate solution was added to adjust the pH to 10. After the precipitation reaction ended, separation, washing and drying were carried out to obtain supported polystyrene microspheres;

[0046] The mass ratio of the above - mentioned mesoporous polystyrene microspheres (prepared in Example 4) to the 5 wt% cobalt chloride solution was 1:10.

[0047] (2) Disperse the supported polystyrene microspheres in a 75 wt% ethanol solution to obtain a 0.2 mg / mL supported polystyrene microsphere ethanol solution. Then add concentrated ammonia water and tetraethyl orthosilicate, and continuously stir and react for 3 h. After separation, washing, drying and grinding, supported silica microspheres are obtained;

[0048] The volume ratio of the above-mentioned supported polystyrene microsphere ethanol solution, concentrated ammonia water and tetraethyl orthosilicate is 100:2:1.

[0049] (3) Place the supported silica microspheres in a muffle furnace and calcine them at 550 °C for 2 h under a carbon monoxide atmosphere to obtain a polysilicon system catalyst.

[0050] Example 7

[0051] A preparation method of a polysilicon catalyst for new energy, comprising the following steps:

[0052] (1) Ultrasonically disperse the mesoporous polystyrene microspheres (prepared in Example 3) in a 5 wt% copper chloride solution, then add a 10 wt% sodium carbonate solution to adjust the pH to 8 - 10. After the precipitation reaction ends, after separation, washing and drying, supported polystyrene microspheres are obtained;

[0053] The mass ratio of the above-mentioned mesoporous polystyrene microspheres (prepared in Example 3) to the 5 wt% copper chloride solution is 1:9.

[0054] (2) Disperse the supported polystyrene microspheres in a 75 wt% ethanol solution to obtain a 0.2 mg / mL supported polystyrene microsphere ethanol solution. Then add concentrated ammonia water and tetraethyl orthosilicate, and continuously stir and react for 2.5 h. After separation, washing, drying and grinding, supported silica microspheres are obtained;

[0055] The volume ratio of the above-mentioned supported polystyrene microsphere ethanol solution, concentrated ammonia water and tetraethyl orthosilicate is 100:2:1.

[0056] (3) Place the supported silica microspheres in a muffle furnace and calcine them at 580 °C for 1.8 h under a carbon monoxide atmosphere to obtain a polysilicon system catalyst.

[0057] Comparative Example 1

[0058] A preparation method of a polysilicon catalyst for new energy is basically the same as that of Example 7, the difference being that: the mesoporous polystyrene microspheres are replaced with the sulfonated polystyrene microspheres prepared in Example 1.

[0059] Performance detection

[0060] 1. Perform the catalytic conversion experiment of tetrachlorosilane on the polysilicon system catalysts in Examples 5 - 7 and Comparative Example 1: Uniformly mix the catalyst and silicon powder in a mass ratio of 10:1 and inject them into the reactor. Purge the reactor with nitrogen to remove air. Heat the reactor temperature to the set temperature of 450°C. Inject tetrachlorosilane into the reactor through a metering pump and mix it with hydrogen. Control the feed rates of tetrachlorosilane and hydrogen so that the hydrogen-silicon ratio (molar ratio) is 4:1. Set the reactor pressure to 3.0 MPa and the reaction temperature to 450°C. Real-time monitor the reaction products at the reactor outlet through an on-line chromatograph to obtain a gas chromatogram. Then, the conversion rate of tetrachlorosilane (%) = (peak area of dichlorosilane + peak area of trichlorosilane) / (peak area of dichlorosilane + peak area of trichlorosilane + peak area of tetrachlorosilane) × 100%.

[0061] 2. Calcinate the polysilicon system catalyst after the above reaction for 72 h at 550°C for 2 h for regeneration, and perform the catalytic conversion experiment of tetrachlorosilane on the regenerated polysilicon system catalyst.

[0062] The specific results are shown in the following table.

[0063] Table 1 Conversion Rate

[0064]

[0065] As can be seen from the above table: The polysilicon system catalysts in the examples have a relatively high conversion rate of tetrachlorosilane and can achieve stable catalysis for a long time. Compared with Example 7, when using the polysilicon system catalyst in Comparative Example 1, the conversion rate of tetrachlorosilane decreases, indicating that the setting of mesopores helps to load a sufficient amount of active copper / cobalt to improve the catalytic effect.

[0066] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a polysilicon catalyst for new energy, characterized in that: The following steps are involved: (1) sequentially subjecting polystyrene microspheres to sulfonation treatment and dissolution treatment to obtain mesoporous polystyrene microspheres; (2) ultrasonically dispersing the mesoporous polystyrene microspheres in a metal salt solution, then adding a precipitant solution to adjust the pH to 8-10, and after the precipitation reaction is completed, separating, washing and drying to obtain supported polystyrene microspheres; (3) dispersing the supported polystyrene microspheres in an ethanol solution, then adding concentrated ammonia and tetraethyl orthosilicate, continuously stirring the reaction, separating, washing, drying and grinding to obtain supported silica microspheres; (4) The supported silica microspheres are placed in a muffle furnace and calcined in a carbon monoxide atmosphere to prepare a polycrystalline silicon system catalyst.

2. The method for preparing a polysilicon catalyst for new energy according to claim 1, characterized in that: In step (1), the sulfonation treatment is specifically as follows: polystyrene microspheres and concentrated sulfuric acid are mixed at a material-liquid ratio of 1:30 g / mL, reacted at 40-45° C. for 15-18 hours, separated, washed and dried to obtain sulfonated polystyrene microspheres.

3. The method for preparing a polysilicon catalyst for new energy according to claim 2, characterized in that: In step (1), the dissolution treatment is specifically as follows: sulfonated polystyrene microspheres are uniformly dispersed in deionized water, then n-heptane is added, reacted at 65-70° C. for 2-2.5 hours, separated, washed and dried to obtain mesoporous polystyrene microspheres.

4. The method for preparing a polysilicon catalyst for new energy according to claim 3, characterized in that: The volume ratio of n-heptane to deionized water is (1-3):10; the material-liquid ratio of sulfonated polystyrene microspheres to deionized water is 5:

1.

5. The method for preparing polysilicon catalyst for new energy according to claim 1, characterized in that: In step (2), the metal salt solution is selected from 5wt% copper chloride solution and 5wt% cobalt chloride solution; and the precipitant is selected from 10wt% sodium carbonate solution.

6. The method for preparing a polysilicon catalyst for new energy according to claim 1, characterized in that: In step (2), the mass ratio of the mesoporous polystyrene microspheres to the metal salt solution is 1:(8-10).

7. The method for preparing polysilicon catalyst for new energy according to claim 1, characterized in that: In step (3), the concentration of the alcoholic solution of polystyrene microspheres formed by the loaded polystyrene microspheres and 75 wt % ethanol solution is 0.2 mg / mL; the volume ratio of the alcoholic solution of polystyrene microspheres, concentrated ammonia water and tetraethyl orthosilicate is 100:2:1; and the reaction is stirred continuously for 2-3 hours.

8. The method for preparing polysilicon catalyst for new energy according to claim 1, characterized in that: In step (4), the calcination temperature is 550-600° C., and the calcination time is 1.5-2 h.

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