Adsorbent for removing boron impurities in trichlorosilane as well as preparation method and application of adsorbent

Abstract

The invention provides an adsorbent for removing boron impurities in trichlorosilane as well as a preparation method and application of the adsorbent. The preparation method comprises the following steps: pretreatment: performing ultrasonic cleaning on an inorganic porous material, and performing drying treatment on the cleaned inorganic porous material; dipping: dissolving an amine organic matter in water to prepare an organic amine solution, mixing the inorganic porous material with the organic amine solution, and dipping in vacuum; drying: putting the inorganic porous material soaked in the organic amine solution into a drying box for drying treatment to obtain the boron impurity adsorbent. According to the preparation method provided by the invention, the inorganic porous material is used as a carrier, the amine compound is loaded on the carrier, and the adsorption effect of the adsorbent on the boron impurities is improved by utilizing the high specific surface area of the inorganic porous material and the complexation reaction of the amine compound and the boron impurities; and moreover, a complex generated by the amine compound and the boron impurities can be desorbed through thermal decomposition, and the adsorbent can be reused, so that the boron removal cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of polysilicon production, and in particular to an adsorbent for removing boron impurities in trichlorosilane, and a preparation method and application thereof. Background Art

[0002] The two major downstream markets of polysilicon, photovoltaics and electronic information, are developing in a high-end direction, with more stringent requirements on the purity of polysilicon raw materials. Some photovoltaic manufacturers in Xinjiang, Gansu and other places even refer to the national standards for electronic-grade polysilicon for silicon materials. High-purity polysilicon has become a strategic material for responding to energy crises and developing the information industry.

[0003] In the polysilicon industry, trichlorosilane is an important raw material for preparing polysilicon, among which the boron impurity content in trichlorosilane is an important factor affecting the quality of polysilicon, and seriously affects the quality index of polysilicon. At present, the boron impurities in trichlorosilane are mainly removed by the separation method of multi-stage distillation in China. However, since the volatility of boron impurities in trichlorosilane is close to that of trichlorosilane, it is necessary to increase the reflux ratio and reduce the extraction volume to ensure the quality index during multi-stage distillation, resulting in low product yield and unstable product quality, and the energy consumption and cost for boron removal remain high.

[0004] The special-effect resins currently used have high boron removal efficiency, but the regeneration process requires strong acids and alkalis, which produces a large amount of acid and alkali waste liquid. In addition, the resin cost is relatively high and there is a risk of combustion in the trichlorosilane system. Summary of the invention

[0005] The purpose of the present application is to provide an adsorbent for removing boron impurities in trichlorosilane, and a preparation method and application thereof. In the preparation method, an inorganic porous material is used as a carrier, and the inorganic porous material is immersed in an organic amine solution, so that the amine organic matter is attached to the inorganic porous material, thereby solving the problem of high cost and flammability of boron removal in the prior art.

[0006] In order to achieve one of the above-mentioned objects of the invention, an embodiment of the present application provides a method for preparing an adsorbent for removing boron impurities in trichlorosilane, comprising the following steps:

[0007] Pretreatment: ultrasonically clean the inorganic porous material, and dry the cleaned inorganic porous material;

[0008] Impregnation: dissolving amine organic matter in water to prepare an organic amine solution, and mixing the inorganic porous material and the organic amine solution, and impregnating under vacuum;

[0009] Drying: The inorganic porous material immersed in the organic amine solution is placed in a drying oven for drying to obtain a boron impurity adsorbent.

[0010] As a further improvement of one embodiment of the present application, the amine organic compound is selected from one or more of N-methyl-D-glucamine, diethylamine, triethylamine, N-methylacetamide, and nitrogenmethylformamide.

[0011] As a further improvement of an embodiment of the present application, the concentration of the organic amine solution is 0.1 to 1 mol / L.

[0012] As a further improvement of an embodiment of the present application, the inorganic porous material is selected from one or more of aluminum oxide, cerium oxide, zinc oxide, 13X molecular sieve, 3A molecular sieve, 4A molecular sieve, and 5A molecular sieve.

[0013] As a further improvement of an embodiment of the present application, the inorganic porous material has a bulk density of 0.5 to 1.0 g / ml and a diameter distribution of 1 to 5 mm.

[0014] As a further improvement of one embodiment of the present application, the specific surface area of ​​the inorganic porous material is 200 to 300 m 2 / g.

[0015] As a further improvement of one embodiment of the present application, in the impregnation step, the inorganic porous material and the organic amine solution are placed in a vacuum container, evacuated to -0.2 to 0 MPa, and the impregnation time is 30 to 90 minutes.

[0016] One embodiment of the present application also provides an adsorbent for removing boron impurities in trichlorosilane, using an inorganic porous material as a carrier, and the carrier is loaded with amine organic matter, wherein the inorganic porous material is selected from one or more of aluminum oxide, cerium oxide, zinc oxide, 13X molecular sieve, 3A molecular sieve, 4A molecular sieve, and 5A molecular sieve.

[0017] As a further improvement of one embodiment of the present application, the amine organic compound is selected from one or more of N-methyl-D-glucamine, diethylamine, triethylamine, N-methylacetamide, and nitrogenmethylformamide.

[0018] An embodiment of the present application further provides a use of the aforementioned adsorbent for removing boron impurities in trichlorosilane, wherein the boron impurity adsorbent is used to adsorb boron impurities in trichlorosilane.

[0019] One or more technical solutions provided by this application have at least the following technical effects or advantages:

[0020] In the preparation method of the adsorbent for removing boron impurities in trichlorosilane provided in the present application, an inorganic porous material is used as a carrier, and the carrier is immersed in an organic amine solution to allow the amine organic matter to adhere to the carrier. On the one hand, the inorganic carrier is resistant to high temperatures and non-flammable, and has a large specific surface area that can achieve rapid adsorption; on the other hand, the lone pair of electrons on N in the amine organic matter can be complexed with boron-containing impurities, further enhancing the adsorption capacity of the adsorbent for boron impurities. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below in conjunction with specific embodiments, but these embodiments do not limit the present invention, and changes in reaction conditions, reactants or raw material amounts made by ordinary technicians in the field according to these embodiments are all included in the protection scope of the present invention.

[0022] The present application provides a method for preparing an adsorbent for removing boron impurities in trichlorosilane, comprising the following steps:

[0023] Pretreatment: ultrasonically clean the inorganic porous material, and dry the cleaned inorganic porous material;

[0024] Impregnation: dissolving amine organic matter in water to prepare an organic amine solution, and mixing the inorganic porous material and the organic amine solution, and impregnating under vacuum;

[0025] Drying: The inorganic porous material immersed in the organic amine solution is placed in a drying oven for drying to obtain a boron impurity adsorbent.

[0026] In the present application, an inorganic porous material is used as a carrier, and the inorganic porous material as a carrier is mixed with an organic amine solution. After being immersed under vacuum, the mixture is dried to remove moisture, so that the amine organic matter in the organic amine solution adheres to the inorganic porous material and the moisture is removed. The amine organic matter and the inorganic porous material are connected by hydrogen bonds, have a certain stability, and finally form a boron impurity adsorbent.

[0027] Inorganic porous materials have strong structural stability and strong adsorption due to their large specific surface area. The lone pair of electrons on the N atom in the amine organic matter can complex with the boron impurity, further improving the adsorption performance. The chemical adsorption of boron impurities by amine organic matter and the physical adsorption of inorganic porous materials are combined, which greatly improves the adsorption efficiency and rate of boron impurities in trichlorosilane by inorganic porous materials loaded with amine organic matter.

[0028] In addition, inorganic porous materials are inorganic substances and are not easy to burn when heated. The boron impurity adsorbent provided by the present application has no combustion risk. Based on the structural stability of inorganic porous materials, the boron impurity adsorbent prepared by the preparation method provided by the present application can be desorbed by heating to decompose the complex produced by amine organic matter and boron impurities, and the porous structure of the inorganic porous material will not collapse, which makes the boron impurity adsorbent extremely recyclable and greatly reduces the cost of removing boron impurities with trichlorosilane.

[0029] In the preparation method provided in the present application, in order to avoid the introduction of new impurities during impurity removal, the inorganic porous material is first ultrasonically cleaned before being immersed in an organic amine solution to remove dust and oil stains on the surface of the inorganic porous material.

[0030] Among them, an ultrasonic cleaner is used for ultrasonic cleaning, the cleaning time is 30 to 60 minutes, and the working frequency of the ultrasonic cleaner is 20kHz to 80kHz to ensure that the inorganic porous material is cleaned. The cleaning agent is any one of deionized water, anhydrous ethanol, and acetone. The aforementioned solvents are easy to evaporate and not easy to remain, which can avoid the introduction of new impurities caused by incomplete drying. Of course, in addition to deionized water, anhydrous ethanol and acetone, other easy-to-dry solvents can also be used.

[0031] After cleaning, the inorganic porous material is placed in a drying oven and dried at a temperature of 80 to 120° C. for 12 to 24 hours. Since there are many pores in the inorganic porous material, it is necessary to ensure that the cleaning agent in the inorganic porous material is completely dried to obtain a clean inorganic porous material after drying.

[0032] In some embodiments, the amine organic compound is selected from one or more of N-methyl-D-glucamine, diethylamine, triethylamine, N-methylacetamide, and nitrogen methylformamide.

[0033] In some embodiments, the concentration of the organic amine solution is 0.1-1 mol / L. These amine organic substances are dissolved in water to form an organic amine solution. For triethylamine, which is slightly soluble in water, the concentration of triethylamine can be increased by ultrasonic dispersion or other methods.

[0034] In some embodiments, the inorganic porous material is selected from one or more of aluminum oxide, cerium oxide, zinc oxide, 13X molecular sieve, 3A molecular sieve, 4A molecular sieve, and 5A molecular sieve. The various inorganic compounds listed above are not flammable and have high melting points, and there is no risk of combustion when exposed to fire. When the boron impurity adsorbent fails to adsorb, heating it can decompose the complex formed by the amine organic matter and the boron impurity, so that the boron impurity adsorbent can be reused. Since the porous material formed by the inorganic substance has a stable structure, its porous structure will not collapse even if it is heated.

[0035] In some embodiments, the inorganic porous material has a bulk density of 0.5-1.0 g / ml and a diameter distribution of 1-5 mm. The aforementioned diameter distribution of the inorganic porous material enables smaller inorganic porous materials to be filled in the pores of larger inorganic porous materials, so that the inorganic porous materials are filled more fully.

[0036] In some embodiments, the specific surface area of ​​the inorganic porous material is 200 to 300 m 2 / g. The larger the specific surface area of ​​an inorganic porous material, the more adsorption sites it has, that is, the stronger its adsorption capacity.

[0037] In some embodiments, in the impregnation step, the inorganic porous material and the organic amine solution are placed in a vacuum container, evacuated to -0.2 to 0 MPa, and the immersion time is 30 to 90 minutes. Since there are many pores in the inorganic porous material, even if the inorganic porous material is completely immersed in the organic amine solution, it is not possible to ensure that the amine organic matter can well enter the numerous pores of the inorganic porous material and adhere to the surface. Vacuuming can promote the adhesion rate and adhesion speed of the amine organic matter on the inorganic porous material.

[0038] After the impregnation is completed, the inorganic porous material is placed in a drying oven for drying to remove the water in the organic amine solution so that only amine organic matter is attached to the surface of the inorganic porous material, wherein the drying temperature is 70 to 110° C. and the drying time is 12 to 36 hours. The drying time is relatively longer than that in the pretreatment step, which can avoid the possibility of residual cleaning agents, such as deionized water, anhydrous ethanol, acetone, etc., in the pores of the inorganic porous material due to incomplete drying in the pretreatment step. The drying time is increased to ensure that the water or cleaning agent in the pores of the inorganic porous material is completely dried.

[0039] The embodiment of the present application also provides an adsorbent for removing boron impurities in trichlorosilane, with an inorganic porous material as a carrier, and an amine organic substance is loaded on the carrier, wherein the inorganic porous material is selected from one or more of aluminum oxide, cerium oxide, zinc oxide, 13X molecular sieve, 3A molecular sieve, 4A molecular sieve, and 5A molecular sieve. The above-mentioned inorganic porous material has a large specific surface area, high structural stability, high melting point and non-combustibility. The lone pair of electrons on N in the amine organic substance can be complexed with boron impurities, so that the adsorbent has a good adsorption effect and efficiency, and the decomposition of the complex can be achieved by heating, and heating will not cause the porous structure of the carrier to collapse, so that the adsorbent has good cyclic regenerative properties, and the adsorbent does not have a combustion risk.

[0040] In some embodiments, the amine organic compound is selected from one or more of N-methyl-D-glucamine, diethylamine, triethylamine, N-methylacetamide, and nitrogen methylformamide.

[0041] The embodiment of the present application also provides an application of an adsorbent for removing boron impurities in trichlorosilane as described above, and the boron impurity adsorbent is used to adsorb boron impurities in trichlorosilane. Based on the characteristics of the adsorbent for boron impurities in the above-mentioned adsorbent, the adsorbent for removing boron impurities in trichlorosilane provided in the embodiment of the present application has a high adsorption rate and adsorption speed when adsorbing boron impurities in trichlorosilane, and is regenerable and non-combustible.

[0042] The technical solution of the present application is further described below in conjunction with some specific embodiments.

[0043] Example 1

[0044] Pretreatment: Add the inorganic porous material alumina to an ultrasonic cleaner filled with deionized water for ultrasonic cleaning. The working frequency of the ultrasonic cleaner is 20Hz. After cleaning for 30 minutes, put the cleaned alumina into a blast drying oven and dry it at 95℃ for 12 hours. Among them, the bulk density of the inorganic porous material alumina is 0.6g / ml, the diameter is distributed in the range of 2 to 4mm, and the specific surface area is 260m 2 / g.

[0045] Impregnation: Weigh 19.5 g of N-methyl-D-glucamine to prepare a 1 mol / L N-methyl-D-glucamine solution, mix the cleaned alumina with the N-methyl-D-glucamine solution and put them into a vacuum container, evacuate the container to -0.1 MPa, and impregnate for 30 minutes.

[0046] Drying: After the impregnation is completed, the alumina impregnated with N-methyl-D-glucamine is placed in a drying oven and dried at a temperature of 100° C. for 24 hours to obtain a boron impurity adsorbent.

[0047] The above synthesized adsorbent was used to adsorb and remove boron impurities in trichlorosilane. The experimental method is as follows:

[0048] Before adsorption, the adsorbent was dried at 150 °C for 4 h.

[0049] Weigh 5g of the prepared adsorbent and add it to 100ml of trichlorosilane solution. Seal the solution containing the adsorbent in a 100mL square-mouthed bottle with a lid, and then oscillate at a constant temperature for 2 hours. After adsorption equilibrium, take the mixed solution for ICP test. The results show that the adsorbent has a removal rate of 95% for boron impurities and a removal rate of 40% for phosphorus impurities.

[0050] Example 2

[0051] Pretreatment: Add the inorganic porous material alumina to an ultrasonic cleaner filled with deionized water for ultrasonic cleaning. The working frequency of the ultrasonic cleaner is 20Hz. After cleaning for 30 minutes, put the cleaned alumina into a blast drying oven and dry it at 95℃ for 12 hours. Among them, the bulk density of the inorganic porous material alumina is 0.6g / ml, the diameter is distributed in the range of 2 to 4mm, and the specific surface area is 260m 2 / g.

[0052] Impregnation: Weigh 7.4 g of diethylamine to prepare a 1 mol / L diethylamine solution, mix the cleaned alumina with the diethylamine solution and put them into a vacuum container, evacuate the container to -0.1 MPa, and impregnate for 30 minutes.

[0053] Drying: After the impregnation is completed, the alumina impregnated with diethylamine is placed in a drying oven and dried at 100° C. for 24 hours to obtain a boron impurity adsorbent.

[0054] The above synthesized adsorbent was used to adsorb and remove boron impurities in trichlorosilane. The experimental method is as follows:

[0055] Before adsorption, the adsorbent was dried at 150 °C for 4 h.

[0056] Weigh 5g of the prepared adsorbent and add it to 100ml of trichlorosilane solution. Seal the solution containing the adsorbent in a 100mL square-mouthed bottle with a lid, and then oscillate at a constant temperature for 2 hours. After adsorption equilibrium, take the mixed solution for ICP test. The results show that the adsorbent has a removal rate of 75% for boron impurities and a removal rate of 38% for phosphorus impurities.

[0057] Example 3

[0058] Pretreatment: Add the inorganic porous material alumina to an ultrasonic cleaner filled with deionized water for ultrasonic cleaning. The working frequency of the ultrasonic cleaner is 20Hz. After cleaning for 30 minutes, put the cleaned alumina into a blast drying oven and dry it at 95℃ for 12 hours. Among them, the bulk density of the inorganic porous material alumina is 0.6g / ml, the diameter is distributed in the range of 2 to 4mm, and the specific surface area is 260m 2 / g.

[0059] Impregnation: Weigh 7.3 g of N-methylacetamide to prepare a 1 mol / L N-methylacetamide solution, mix the cleaned alumina with the N-methylacetamide solution and put them into a vacuum container, evacuate the container to -0.1 MPa, and impregnate for 30 minutes.

[0060] Drying: After the impregnation is completed, the alumina impregnated with N-methylacetamide is placed in a drying oven and dried at a temperature of 100° C. for 24 hours to obtain a boron impurity adsorbent.

[0061] The above synthesized adsorbent was used to adsorb and remove boron impurities in trichlorosilane. The experimental method is as follows:

[0062] Before adsorption, the adsorbent was dried at 150 °C for 4 h.

[0063] Weigh 5g of the prepared adsorbent and add it to 100ml of trichlorosilane solution. Seal the solution containing the adsorbent in a 100mL square-mouthed bottle with a lid, and then oscillate at a constant temperature for 2 hours. After adsorption equilibrium, take the mixed solution for ICP test. The results show that the adsorbent has a removal rate of 72% for boron impurities and a removal rate of 39% for phosphorus impurities.

[0064] Example 4

[0065] Pretreatment: Add the inorganic porous material cerium oxide to an ultrasonic cleaner filled with deionized water for ultrasonic cleaning. The working frequency of the ultrasonic cleaner is 20Hz. After cleaning for 30 minutes, put the cleaned cerium oxide into a blast drying oven and dry it at 95℃ for 12 hours. Among them, the bulk density of the inorganic porous material cerium oxide is 0.6g / ml, the diameter is distributed in the range of 2 to 4mm, and the specific surface area is 260m 2 / g.

[0066] Impregnation: Weigh 19.5 g of N-methyl-D-glucamine to prepare a 1 mol / L N-methyl-D-glucamine solution, mix the cleaned cerium oxide with the N-methyl-D-glucamine solution and put them into a vacuum container, evacuate the container to -0.1 MPa, and impregnate for 30 minutes.

[0067] Drying: After the impregnation is completed, the cerium oxide impregnated with N-methyl-D-glucamine is placed in a drying oven and dried at a temperature of 100° C. for 24 hours to obtain a boron impurity adsorbent.

[0068] The above synthesized adsorbent was used to adsorb and remove boron impurities in trichlorosilane. The experimental method is as follows:

[0069] Before adsorption, the adsorbent was dried at 150 °C for 4 h.

[0070] Weigh 5g of the prepared adsorbent and add it to 100ml of trichlorosilane solution. Seal the solution containing the adsorbent in a 100mL square-mouthed bottle with a lid, and then oscillate at a constant temperature for 2 hours. After adsorption equilibrium, take the mixed solution for ICP test. The results show that the adsorbent has a removal rate of 92% for boron impurities and a removal rate of 43% for phosphorus impurities.

[0071] Example 5

[0072] Pretreatment: Add the inorganic porous material 3A molecular sieve to an ultrasonic cleaner filled with deionized water for ultrasonic cleaning. The working frequency of the ultrasonic cleaner is 20Hz. After cleaning for 30 minutes, put the cleaned 3A molecular sieve into a blast drying oven and dry it at 95℃ for 12 hours. Among them, the bulk density of the inorganic porous material cerium oxide is 0.6g / ml, the diameter is distributed in the range of 2 to 4mm, and the specific surface area is 260m 2 / g.

[0073] Impregnation: Weigh 19.5 g of N-methyl-D-glucamine to prepare a 1 mol / L N-methyl-D-glucamine solution, mix the cleaned 3A molecular sieve with the N-methyl-D-glucamine solution and put them into a vacuum container, evacuate the container to -0.1 MPa, and impregnate for 30 minutes.

[0074] Drying: After the impregnation is completed, the 3A molecular sieve impregnated with N-methyl-D-glucamine is placed in a drying oven and dried at a temperature of 100° C. for 24 hours to obtain a boron impurity adsorbent.

[0075] The above synthesized adsorbent was used to adsorb and remove boron impurities in trichlorosilane. The experimental method is as follows:

[0076] Before adsorption, the adsorbent was dried at 150 °C for 4 h.

[0077] Weigh 5g of the prepared adsorbent and add it to 100ml of trichlorosilane solution. Seal the solution containing the adsorbent in a 100mL square-mouthed bottle with a lid, and then oscillate at a constant temperature for 2 hours. After adsorption equilibrium, take the mixed solution for ICP test. The results show that the adsorbent has a removal rate of 88% for boron impurities and a removal rate of 40% for phosphorus impurities.

[0078] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0079] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present application. They are not intended to limit the scope of protection of the present application. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present application should be included in the scope of protection of the present application.

Claims

1. A method for preparing an adsorbent for removing boron impurities in trichlorosilane, characterized in that: The steps include: Pretreatment: ultrasonically clean the inorganic porous material, and dry the cleaned inorganic porous material; Impregnation: dissolving amine organic matter in water to prepare an organic amine solution, and mixing the inorganic porous material and the organic amine solution, and impregnating under vacuum; Drying: The inorganic porous material immersed in the organic amine solution is placed in a drying oven for drying to obtain a boron impurity adsorbent.

2. The method for preparing an adsorbent for removing boron impurities in trichlorosilane according to claim 1, characterized in that: The amine organic compound is selected from one or more of N-methyl-D-glucamine, diethylamine, triethylamine, N-methylacetamide and nitrogen methylformamide.

3. The method for preparing an adsorbent for removing boron impurities in trichlorosilane according to claim 2, characterized in that: The concentration of the organic amine solution is 0.1 to 1 mol / L.

4. The method for preparing an adsorbent for removing boron impurities in trichlorosilane according to claim 1, characterized in that: The inorganic porous material is selected from one or more of aluminum oxide, cerium oxide, zinc oxide, 13X molecular sieve, 3A molecular sieve, 4A molecular sieve, and 5A molecular sieve.

5. The method for preparing an adsorbent for removing boron impurities in trichlorosilane according to claim 4, characterized in that: The bulk density of the inorganic porous material is 0.5-1.0 g / ml, and the diameter distribution is 1-5 mm.

6. The method for preparing an adsorbent for removing boron impurities in trichlorosilane according to claim 5, characterized in that: The specific surface area of ​​inorganic porous materials is 200-300m 2 / g.

7. The method for preparing an adsorbent for removing boron impurities in trichlorosilane according to claim 1, characterized in that: In the impregnation step, the inorganic porous material and the organic amine solution are placed in a vacuum container, evacuated to -0.2 to 0 MPa, and the impregnation time is 30 to 90 minutes.

8. An adsorbent for removing boron impurities from trichlorosilane, characterized in that: An inorganic porous material is used as a carrier, and an amine organic substance is loaded on the carrier, wherein the inorganic porous material is selected from one or more of aluminum oxide, cerium oxide, zinc oxide, 13X molecular sieve, 3A molecular sieve, 4A molecular sieve, and 5A molecular sieve.

9. The adsorbent for removing boron impurities in trichlorosilane according to claim 8, characterized in that: The amine organic compound is selected from one or more of N-methyl-D-glucamine, diethylamine, triethylamine, N-methylacetamide and nitrogen methylformamide.

10. Use of an adsorbent for removing boron impurities from trichlorosilane as claimed in claim 8 or 9, characterized in that: The boron impurity adsorbent is used for adsorbing boron impurities in trichlorosilane.