Method and device for purifying high-purity boron trifluoride 11

Abstract

The invention relates to a purification method of high-purity boron trifluoride 11, which comprises the following steps: S1, carrying out nitrogen purging and replacement on a purification device of boron trifluoride 11, and keeping the moisture content to be less than 1ppm; s2, the boron trifluoride 11 raw material is subjected to adsorption impurity removal, part of HF impurities are removed, and mixed gas is obtained; s3, rectifying the mixed gas obtained in the step S2 to remove light components, so as to obtain a mixed solution; s4, rectifying the mixed solution obtained in S3 again to remove heavy components, so as to obtain high-purity boron trifluoride 11; and S5, collecting the high-purity boron trifluoride 11 into a cold trap, and filling the cold trap with the high-purity boron trifluoride 11. According to the technical scheme provided by the invention, the purchased product is introduced into the rectifying tower to remove light components and heavy components so as to obtain a high-purity product, and light components and heavy component impurities such as H2, O2, Ar, N2, CO2, SO2, HF and SiF4 in boron trifluoride 11 are effectively removed through accurate control of the rectifying process, so that a high-purity 5N-grade boron trifluoride 11 product can be obtained, and the requirement of high-end application is met.

Description

Technical Field

[0001] The present invention relates to the field of fine chemical purification, and in particular to a purification method and device for high-purity boron trifluoride 11. Background Art

[0002] Boron trifluoride is a colorless gas with asphyxiation. When it encounters moisture in the air, it immediately decomposes into fluoroboric acid and boric acid. High-purity boron trifluoride is used in the electronics industry as a P-type doping source for the epitaxy, diffusion and ion implantation of silicon and germanium. It can also be used as a raw material for preparing optical fiber preforms. It is used as a boron dopant in silicon ion implantation. The chips produced have the characteristics of high integration and high density. Boron elements are divided into boron-10 and boron-11. Boron-10 has a very strong adsorption capacity for fast neutrons and is increasingly used in nuclear power, modern industry, military equipment, etc. The integrated circuit chips produced by the boron-11 isotope as a semiconductor doping for integrated circuits have extremely strong radiation resistance and single particle effect resistance. Boron trifluoride 11 is a consumable material in the semiconductor manufacturing process. Against the backdrop of the eastward shift of the global semiconductor industry, domestic semiconductor companies have rapidly increased their demand for high-purity, high-abundance boron trifluoride 11. However, the production technology barriers for boron trifluoride 11 are high and its production capacity is low. my country's market demand mainly relies on imports, but the unit price of imported boron trifluoride 11 is high. Under the current circumstances, boron trifluoride 11 urgently needs to be produced domestically.

[0003] With the rapid development of the electronics industry, the requirements for the purity of boron trifluoride 11 are also increasing. In the preparation process of boron trifluoride 11, due to the different preparation methods, there are many types of impurities in the synthesis process. Common impurities include oxygen, nitrogen, carbon dioxide, carbon monoxide, silicon tetrafluoride, sulfur dioxide and hydrogen fluoride. At present, hydrogen fluoride impurities in electronic gases are mainly removed by distillation or water washing, but because boron trifluoride is easily soluble in water, the above methods are difficult to apply. Summary of the invention

[0004] The object of the present invention is to provide a method and apparatus for purifying high-purity boron trifluoride 11, so as to solve the problems that the existing preparation of high-purity boron trifluoride 11 products does not meet the requirements, the product purity is unstable and the process is complicated.

[0005] The specific technical solutions of the present invention are as follows:

[0006] A method for purifying high-purity boron trifluoride 11 comprises the following steps:

[0007] S1. Purging and replacing the boron trifluoride 11 purification device with nitrogen to maintain the moisture content <1ppm;

[0008] S2, subjecting the boron trifluoride 11 raw material to sodium fluoride adsorption to remove part of the HF impurities, the adsorption temperature is 10-70°C, the regeneration temperature is 200-300°C, and a mixed gas is obtained;

[0009] S3, removing light components from the mixed gas obtained in S2 by distillation to obtain a mixed liquid;

[0010] S4, subjecting the mixed solution obtained in S3 to distillation again to remove heavy components, thereby obtaining high-purity boron trifluoride 11;

[0011] S5. Collect high-purity boron trifluoride 11 into a cold trap and fill it.

[0012] Preferably, the method further comprises step S6, collecting the light components removed in step S3 and the heavy components removed in step S4 into a three-waste cold trap, and then purifying them through a primary separation tower to make the mass fraction content of boron trifluoride 11 ≥99%, and further purifying them as a raw material.

[0013] Preferably, in step S6, the operating temperature of the three-waste cold trap is -120 to -100°C.

[0014] Preferably, in step S2, the mass fraction content of boron trifluoride 11 is greater than or equal to 99%.

[0015] Preferably, in step S2, the flow rate of the boron trifluoride 11 raw material for purification is 0.5-2 kg / h.

[0016] Preferably, in step S3, the operating temperature for removing light components by distillation operation is -90 to -60°C, the operating pressure is 0.3 to 0.8 MPa, the reflux ratio is 5 to 10, and the light component impurities removed include: H2, O2, Ar, N2 and part of boron trifluoride 11.

[0017] Preferably, in step S4, the operating temperature for removing heavy components by distillation operation is -80 to 60°C, the operating pressure is 0.2 to 0.7 MPa, the reflux ratio is 5 to 10, and the removed heavy component impurities include: CO2, SO2, HF, SiF4 and part of boron trifluoride 11.

[0018] Preferably, in step S5, the operating temperature of the cold trap is -120 to -100°C.

[0019] The present invention also provides a purification device for high-purity boron trifluoride 11, comprising an adsorption tower, a lightness removal tower, a weight removal tower, a collection cold trap, a membrane press and a product cylinder connected in sequence by pipelines, a raw material input pipeline is connected to a feed port at the bottom of the adsorption tower through a pipeline, a mass flow controller is arranged on the pipeline, a discharge port at the top of the adsorption tower is connected to a feed port in the middle of the lightness removal tower through a pipeline, the bottom of the lightness removal tower is connected to the middle of the weight removal tower through a pipeline, the top of the weight removal tower is connected to a collection cold trap through a pipeline, the collection cold trap is connected to a membrane press through a pipeline, and the membrane press is connected to a collection cylinder through a pipeline; the top of the lightness removal tower is connected to a three-waste cold trap through a pipeline, the bottom of the weight removal tower is connected to the three-waste cold trap through a pipeline, the three-waste cold trap is connected to the middle of a primary separation tower through a pipeline, and the bottom of the primary separation tower is connected to the raw material input pipeline.

[0020] The purification method and device of high-purity boron trifluoride 11 of the present invention have the following advantages: the technical scheme of the present invention passes the purchased product into a distillation tower to remove light components and heavy components to obtain a high-purity product, and through precise control of the distillation process, the light components and heavy impurities in boron trifluoride 11, such as H2, O2, Ar, N2, CO2, SO2, HF, SiF4, etc., are effectively removed, thereby obtaining a high-purity 5N grade boron trifluoride 11 product to meet the needs of high-end applications.

[0021] During the preparation stage of the purification device, nitrogen is purged and replaced to ensure that the moisture content in the system is less than 1ppm, which greatly reduces the loss of boron trifluoride 11; the raw material is passed through an adsorption tower to remove some HF impurities to prevent corrosion to subsequent equipment.

[0022] Optimizing the distillation operating temperature and pressure range, as well as the reasonable reflux ratio setting, not only improves the purification efficiency, but also effectively reduces energy consumption, making the production process more economical and efficient.

[0023] For the sake of environmental protection and reuse, the light and heavy components collected by the light removal tower and the heavy removal tower are collected and recycled; the process is emission-free and pollution-free. The technical solution is mature, the steps are simple, environmentally friendly and the product quality is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the purification device of the present invention;

[0025] Explanation of the markings in the figure: 1. Adsorption tower; 2. Light-removal tower; 3. Heavy-removal tower; 4. Three-waste cold trap; 5. Primary separation tower 6. Collection cold trap; 7. Membrane press; 8. Steel cylinder. DETAILED DESCRIPTION

[0026] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0027] Example 1

[0028] like Figure 1 As shown, the purification method of high-purity boron trifluoride 11 of the present invention comprises the following steps:

[0029] S1. Purging and replacing the boron trifluoride 11 purification device with nitrogen to maintain the moisture content <1ppm;

[0030] S2, the boron trifluoride 11 raw material is fed into the adsorption tower 1 at a flow rate of 0.5kg / h through a mass flow controller, the mass fraction content of boron trifluoride 11 in the raw material is greater than or equal to 99%, and part of the HF impurities are removed by sodium fluoride adsorption, the adsorption temperature is 40°C, and a mixed gas is obtained, and the sodium fluoride adsorbent regeneration temperature is 250°C;

[0031] S3, the mixed gas obtained in S2 is sent to the light-removal tower 2, the operating temperature of the top of the light-removal tower 2 is -90 ° C, the operating pressure is 0.3 MPa, the reflux ratio is 10, and the light components are removed by distillation. The removed light component impurities include: H2, O2, Ar, N2 and part of boron trifluoride 11. The total light component (H2, O2+Ar, N2) is less than 1ppm after detection. At this time, a mixed liquid is obtained at the bottom of the light-removal tower 2;

[0032] S4, the mixed liquid obtained in step S3 is sent from the bottom of the light removal tower 2 to the middle of the heavy removal tower 3, the top operating temperature of the heavy removal tower 3 is -80 ° C, the operating pressure is 0.7 MPa, the reflux ratio is 10, and the heavy components are removed by distillation again. The removed heavy component impurities include: CO2, SO2, HF, SiF4 and part of boron trifluoride 11. The total amount of heavy components is less than 10ppm after detection, and high-purity boron trifluoride 11 is obtained;

[0033] S5, the high-purity boron trifluoride 11 obtained in S4 is sent from the top of the deweighting tower 3 to the collection cold trap 6, the operating temperature of the collection cold trap 6 is -120 ° C, the pressure is 0.12MPa, and then passed through the membrane press 7, filled into the product cylinder 8. After testing, the mass fraction of the final product boron trifluoride 11 is greater than 5N, H2 = 0.18ppm, HF = 4.4ppm, SiF4 = 4.3ppm;

[0034] S6. The light components removed in step S3 and the heavy components removed in step S4 are collected into three-waste cold trap 4, the operating temperature of the three-waste cold trap 4 is -120°C, and then purified by primary separation tower 5, the operating temperature of primary separation tower 5 is -90°C, the operating pressure is 0.3MPa, and the reflux ratio is 5, so that the mass fraction content of boron trifluoride 11 is ≥99%, and further purified as raw material.

[0035] Example 2

[0036] The purification method of high-purity boron trifluoride 11 of the present invention comprises the following steps:

[0037] S1. Purging and replacing the boron trifluoride 11 purification device with nitrogen to maintain the moisture content <1ppm;

[0038] S2, the boron trifluoride 11 raw material is fed into the adsorption tower 1 at a flow rate of 1kg / h through a mass flow controller, the mass fraction content of boron trifluoride 11 in the raw material is greater than or equal to 99%, and part of the HF impurities are removed by sodium fluoride adsorption, the adsorption temperature is 10°C, and a mixed gas is obtained, and the sodium fluoride adsorbent regeneration temperature is 200°C;

[0039] S3, the mixed gas obtained in S2 is sent to the light-removal tower 2, the operating temperature of the top of the light-removal tower 2 is -75 ° C, the operating pressure is 0.5 MPa, the reflux ratio is 8, and the light components are removed by distillation. The removed light component impurities include: H2, O2, Ar, N2 and part of boron trifluoride 11. The total light component (H2, O2+Ar, N2) is less than 1ppm after detection. At this time, a mixed liquid is obtained at the bottom of the light-removal tower 2;

[0040] S4, the mixed liquid obtained in step S3 is sent from the bottom of the light removal tower 2 to the middle of the heavy removal tower 3, the top operating temperature of the heavy removal tower 3 is -20 ° C, the operating pressure is 0.4 MPa, the reflux ratio is 7, and the heavy components are removed again by distillation. The removed heavy component impurities include: CO2, SO2, HF, SiF4 and part of boron trifluoride 11. The total amount of heavy components is less than 10ppm after detection, and high-purity boron trifluoride 11 is obtained;

[0041] S5, the high-purity boron trifluoride 11 obtained in S4 is sent from the top of the deweighting tower 3 to the collection cold trap 6, the operating temperature of the collection cold trap 6 is -100 ° C, the pressure is 0.12MPa, and then passed through the membrane press 7, filled into the product cylinder 8. After testing, the mass fraction of the final product boron trifluoride 11 is greater than 5N, H2 = 0.21ppm, HF = 4.3ppm, SiF4 = 4.4ppm;

[0042] S6. The light components removed in step S3 and the heavy components removed in step S4 are collected into three-waste cold trap 4, the operating temperature of the three-waste cold trap 4 is -100°C, and then purified by primary separation tower 5, the operating temperature of primary separation tower 5 is -60°C, the operating pressure is 0.8MPa, and the reflux ratio is 10, so that the mass fraction content of boron trifluoride 11 is ≥99%, and it is further purified as a raw material.

[0043] Example 3

[0044] The method for purifying high-purity boron trifluoride 11 of the present invention comprises the following steps:

[0045] S1. Purging and replacing the boron trifluoride 11 purification device with nitrogen to maintain the moisture content <1ppm;

[0046] S2, the boron trifluoride 11 raw material is fed into the adsorption tower 1 at a flow rate of 2kg / h through a mass flow controller, the mass fraction content of boron trifluoride 11 in the raw material is greater than or equal to 99%, and part of the HF impurities are removed by sodium fluoride adsorption, the adsorption temperature is 70°C, and a mixed gas is obtained, and the sodium fluoride adsorbent regeneration temperature is 300°C;

[0047] S3, the mixed gas obtained in S2 is sent to the light-removal tower 2, the operating temperature of the top of the light-removal tower 2 is -60 ° C, the operating pressure is 0.8 MPa, the reflux ratio is 5, and the light components are removed by distillation. The removed light component impurities include: H2, O2, Ar, N2 and part of boron trifluoride 11. The total light component (H2, O2+Ar, N2) is less than 1ppm after detection. At this time, a mixed liquid is obtained at the bottom of the light-removal tower 2;

[0048] S4, the mixed liquid obtained in step S3 is sent from the bottom of the light removal tower 2 to the middle of the heavy removal tower 3, the operating temperature of the top of the heavy removal tower 3 is 60°C, the operating pressure is 0.2MPa, the reflux ratio is 5, and the heavy components are removed again by distillation. The removed heavy component impurities include: CO2, SO2, HF, SiF4 and part of boron trifluoride 11. The total amount of heavy components is less than 10ppm after detection, and high-purity boron trifluoride 11 is obtained;

[0049] S5, the high-purity boron trifluoride 11 obtained in S4 is sent from the top of the deweighting tower 3 to the collection cold trap 6, the operating temperature of the collection cold trap 6 is -110 ° C, the pressure is 0.12 MPa, and then passed through the membrane press 7, filled into the product cylinder 8. After testing, the mass fraction of the final product boron trifluoride 11 is greater than 5N, H2 = 0.16ppm, HF = 4.1ppm, SiF4 = 4.2ppm;

[0050] S6. The light components removed in step S3 and the heavy components removed in step S4 are collected into three-waste cold trap 4, the operating temperature of the three-waste cold trap 4 is -110°C, and then purified by primary separation tower 5, the operating temperature of primary separation tower 5 is -80°C, the operating pressure is 0.5MPa, and the reflux ratio is 7, so that the mass fraction content of boron trifluoride 11 is ≥99%, and further purified as raw material.

[0051] Example 4

[0052] The invention discloses a purification device for high-purity boron trifluoride 11, comprising an adsorption tower 1, a lightness removal tower 2, a weight removal tower 3, a collection cold trap 6, a membrane press 7 and a product cylinder 8 which are sequentially connected by pipelines, wherein a raw material input pipeline is connected to a feed port at the bottom of the adsorption tower 1 through a pipeline, a mass flow controller is arranged on the pipeline, a discharge port at the top of the adsorption tower 1 is connected to a feed port at the middle of the lightness removal tower 2 through a pipeline, the bottom of the lightness removal tower 2 is connected to the middle of the weight removal tower 3 through a pipeline, the top of the weight removal tower 3 is connected to the collection cold trap 6 through a pipeline, the collection cold trap 6 is connected to the membrane press 7 through a pipeline, the membrane press 7 is connected to the collection cylinder 8 through a pipeline; the top of the lightness removal tower 2 is connected to a three-waste cold trap 4 through a pipeline, the bottom of the weight removal tower 3 is connected to the three-waste cold trap 4 through a pipeline, the three-waste cold trap 4 is connected to the middle of a primary separation tower 5 through a pipeline, and the bottom of the primary separation tower 5 is connected to the raw material input pipeline.

[0053] The technical solution of the present invention is to pass the purchased products into a distillation tower to remove light components and heavy components to obtain a high-purity product. Through precise control of the distillation process, light components and heavy impurities in boron trifluoride 11, such as H2, O2, Ar, N2, CO2, SO2, HF, SiF4, etc., are effectively removed, thereby obtaining a high-purity 5N grade boron trifluoride 11 product to meet the needs of high-end applications.

[0054] During the preparation stage of the purification unit, nitrogen purging and replacement were performed to ensure that the moisture content in the system was less than 1 ppm, which greatly reduced the loss of boron trifluoride 11.

[0055] The optimized distillation operating temperature and pressure range, as well as the reasonable reflux ratio setting, not only improve the purification efficiency, but also effectively reduce energy consumption, making the production process more economical and efficient.

[0056] For the sake of environmental protection and reuse, the light and heavy components collected by the light removal tower 2 and the heavy removal tower 3 are collected and recycled; this technical solution has mature process, simple steps, environmental protection and high product quality.

[0057] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for purifying high-purity boron trifluoride 11, characterized in that: The following steps are involved: S1. Purging and replacing the boron trifluoride 11 purification device with nitrogen to maintain the moisture content <1ppm; S2, subjecting the boron trifluoride 11 raw material to sodium fluoride adsorption to remove part of the HF impurities, the adsorption temperature is 10-70°C, the regeneration temperature is 200-300°C, and a mixed gas is obtained; S3, removing light components from the mixed gas obtained in S2 by distillation to obtain a mixed liquid; S4, subjecting the mixed solution obtained in S3 to distillation again to remove heavy components, thereby obtaining high-purity boron trifluoride 11; S5. Collect high-purity boron trifluoride 11 into a cold trap and fill it.

2. A method for purifying high-purity boron trifluoride 11 according to claim 1, characterized in that: The method further comprises step S6, collecting the light components removed in step S3 and the heavy components removed in step S4 into a three-waste cold trap, and then purifying them through a primary separation tower to make the mass fraction content of boron trifluoride 11 ≥99%, and further purifying them as raw materials.

3. A method for purifying high-purity boron trifluoride 11 according to claim 2, characterized in that: In step S6, the operating temperature of the three waste cold traps is -120 to -100°C.

4. A method for purifying high-purity boron trifluoride 11 according to claim 2, characterized in that: In step S6, the operating temperature of the primary tower is -90 to -60°C, the operating pressure is 0.3 to 0.8 MPa, and the reflux ratio is 5 to 10.

5. The method for purifying high-purity boron trifluoride 11 according to claim 1, characterized in that: In step S2, the mass fraction content of boron trifluoride 11 is greater than or equal to 99%.

6. The method for purifying high-purity boron trifluoride 11 according to claim 1, characterized in that: In step S2, the flow rate of the boron trifluoride 11 raw material for purification is 0.5 to 2 kg / h.

7. The method for purifying high-purity boron trifluoride 11 according to claim 1, characterized in that: In step S3, the operating temperature for removing light components by distillation operation is -90 to -60°C, the operating pressure is 0.3 to 0.8 MPa, the reflux ratio is 5 to 10, and the light component impurities removed include: H2, O2, Ar, N2 and part of boron trifluoride 11.

8. The method for purifying high-purity boron trifluoride 11 according to claim 1, characterized in that: In step S4, the operating temperature for removing heavy components by distillation operation is -80 to 60°C, the operating pressure is 0.2 to 0.7 MPa, the reflux ratio is 5 to 10, and the removed heavy component impurities include: CO2, SO2, HF, SiF4 and part of boron trifluoride 11.

9. The method for purifying high-purity boron trifluoride 11 according to claim 1, characterized in that: In step S5, the operating temperature of the cold trap is -120 to -100°C.

10. A purification device for high-purity boron trifluoride 11, used in the purification method for high-purity boron trifluoride 11 according to any one of claims 1 to 9, characterized in that: It comprises an adsorption tower, a lightness removal tower, a heaviness removal tower, a collection cold trap, a membrane press and a product cylinder which are connected in sequence by pipelines. A raw material input pipeline is connected to a feed port at the bottom of the adsorption tower through a pipeline, a mass flow controller is arranged on the pipeline, a discharge port at the top of the adsorption tower is connected to a feed port in the middle of the lightness removal tower through a pipeline, the bottom of the lightness removal tower is connected to the middle of the heaviness removal tower through a pipeline, the top of the heaviness removal tower is connected to a collection cold trap through a pipeline, the collection cold trap is connected to a membrane press through a pipeline, and the membrane press is connected to a collection cylinder through a pipeline; the top of the lightness removal tower is connected to a three-waste cold trap through a pipeline, the bottom of the heaviness removal tower is connected to the three-waste cold trap through a pipeline, the three-waste cold trap is connected to the middle of a primary separation tower through a pipeline, and the bottom of the primary separation tower is connected to a raw material input pipeline.

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