阅读说明：本技术 一种制备高丰度硼10碳化硼的方法 (Method for preparing high-abundance boron 10 boron carbide ) 是由 于景东 张斌 庞蕾 刘喜民 孙国新 昃向君 于 2020-09-03 设计创作，主要内容包括：本发明提供了一种制备高丰度硼10碳化硼的方法,包括：S1：以氟化氢和硼酸为原料,在三氧化硫氛围下,制备得到三氟化硼；S2：收集三氟化硼气体,并经三级精馏脱除杂质,得到纯化后的三氟化硼气体；S3：以纯化后的三氟化硼气体和二乙二醇二甲醚为原料,进行络合反应,然后将络合物解络合,得到富集硼-10的硼-10三氟化硼气体；S4：以富集硼-10的硼-10三氟化硼气体和水为原料,制备得到富集硼-10的硼-10硼酸；S5：以硼-10硼酸为原料,制备得到硼-10硼酸粉末；S6：以硼-10硼酸粉末和碳粉为原料,在高温电炉中进行还原反应,得到硼-10碳化硼。本发明提供的制备高丰度硼-10碳化硼的方法,生成的硼-10碳化硼的丰度可以高达96％以上,且纯度可高达99.999％,兼顾了高丰度与高纯度。(The invention provides a method for preparing high-abundance boron 10 boron carbide, which comprises the following steps: s1: preparing boron trifluoride by taking hydrogen fluoride and boric acid as raw materials in a sulfur trioxide atmosphere; s2: collecting boron trifluoride gas, and removing impurities through three-stage rectification to obtain purified boron trifluoride gas; s3: carrying out complexation reaction on purified boron trifluoride gas and diethylene glycol dimethyl ether serving as raw materials, and then decomplexing a complex to obtain boron-10 boron trifluoride gas enriched with boron-10; s4: preparing boron-10-enriched boron-10 boric acid by using boron-10-enriched boron-10 trifluoride gas and water as raw materials; s5: preparing boron-10 boric acid powder by taking boron-10 boric acid as a raw material; s6: boron-10 boric acid powder and carbon powder are used as raw materials to carry out reduction reaction in a high-temperature electric furnace to obtain boron-10 boron carbide. According to the method for preparing the high-abundance boron-10-boron carbide, the abundance of the generated boron-10-boron carbide can reach more than 96%, the purity can reach 99.999%, and both high abundance and high purity are taken into consideration.)

1. A method for preparing abundant boron 10 boron carbide is characterized by comprising the following steps:

s1: preparing boron trifluoride by taking hydrogen fluoride and boric acid as raw materials in a sulfur trioxide atmosphere;

s2: collecting boron trifluoride gas generated in the reaction in the S1, and removing impurities through three-stage rectification to obtain purified boron trifluoride gas;

s3: carrying out complexation reaction by using the boron trifluoride gas purified in the S2 and diethylene glycol dimethyl ether as raw materials, and then decomplexing a complex to obtain boron-10 boron trifluoride gas enriched with boron-10;

s4: preparing boron-10 boric acid enriched with boron-10 by using the boron-10 trifluoride gas enriched with boron-10 in S3 and water as raw materials;

s5: preparing boron-10 boric acid powder by using the boron-10 boric acid obtained in the S4 as a raw material;

s6: and (3) taking the boron-10 boric acid powder obtained in the step (S5) and carbon powder as raw materials, and carrying out reduction reaction in a high-temperature electric furnace to obtain boron-10 boron carbide.

2. The method for preparing abundant boron 10 carbide of claim 1, wherein the abundance ratio of the prepared boron-10 carbide in S6 is greater than or equal to 96%, and the purity is greater than or equal to 99.999%.

3. The method for preparing abundant boron 10 carbide according to claim 1, wherein in the S1, the molar ratio of raw material components is as follows: HF: H₃BO₃:SO₃＝(1-3):(1-3):(2-6)。

4. The method for preparing abundant boron 10 carbide according to claim 3, wherein in the S1, the molar ratio of the raw material components is as follows: HF: H₃BO₃:SO₃＝1:1:2。

5. The method for preparing abundant boron 10 carbide according to claim 1, wherein the reaction temperature of hydrogen fluoride and boric acid in S1 is 80-99 ℃.

6. The method for preparing abundant boron 10 carbide according to claim 1, wherein in S2, the process of removing impurities from boron trifluoride gas by three-stage rectification specifically comprises: the first stage of rectification is light component removal rectification, and the rectification temperature is-10 ℃ to-20 ℃; the second-stage rectification is the heavy component removal rectification, and the rectification temperature is-12 to-22 ℃; the third stage of rectification is carried out in a rectifying tower, the temperature of the bottom of the rectifying tower is-12 to-15 ℃, the temperature of the top of the rectifying tower is-15 to-25 ℃, and the purity of boron trifluoride extracted from a measuring line of the rectifying tower is more than or equal to 99.999 percent.

7. The method for preparing abundant boron 10 carbide according to claim 1, wherein in the S3, the molar ratio of raw material components is as follows: boron trifluoride: diethylene glycol dimethyl ether is 1: 30-50; the temperature of the complex reaction is 15-40 ℃; the temperature of the decomplexation reaction is 120-180 ℃.

8. The method as claimed in claim 1, wherein in S3, the number of complexation and decomplexation reactions of the complex between boron trifluoride gas and diethylene glycol dimethyl ether is multiple, and the number of complexation-decomplexation cycle reactions is 150-120 times, so as to obtain boron-10-enriched boron trifluoride gas with an abundance of 96%.

9. The method for preparing abundant boron 10 boron carbide according to claim 1, wherein in the step S5, boron-10 boric acid powder is prepared by using boron-10 boric acid as a raw material and adopting a crystallization-purification-recrystallization method.

10. The method for preparing abundant boron 10 carbide according to claim 1, wherein in the S6, the molar ratio of raw material components is as follows: boron-10 boric acid powder and carbon powder with the purity of more than or equal to 99.999 percent are 3-4: 1.

Technical Field

The invention relates to the field of chemical synthesis, in particular to a method for preparing high-abundance boron 10 boron carbide.

Background

Natural boron (B) has two stable isotopes, i.e.¹⁰B and¹¹b, 19.78% and 80.22% abundance, respectively. The thermal neutron absorption cross section of boron-10 is as high as 3837 bar, about 8 ten thousand times of 11B and 5.12 times of natural B, and the absorption spectrum of boron-10 is wide, and after neutron absorption, strong secondary radiation is not generated, so that the post-treatment is easy, and the radiation-proof effect in a radiation-proof safety control system and medical facilities in nuclear energy and national defense industries is obvious. And the boron carbide (B4C) is used as a neutron absorption material, the absorption capacity of the boron carbide mainly depends on the content of boron-10 in the boron carbide, so that the boron-10-enriched boron carbide (boron-104C) is used for replacing natural abundance boron carbide (B4C), the total material consumption can be greatly reduced, and the neutron absorption efficiency is improved.

At present, no boron-10 boron carbide product with abundance of more than or equal to 96% and purity of more than or equal to 99.999% exists in China, and boron-10 boric acid is produced by adopting a boron trifluoride-methyl ether method, but the boron-10 boric acid is still in a hundred kilogram level test stage at present due to the problems of technology and safety. In addition, the boron trifluoride-anisole method is tried, the abundance of the obtained boron-10 can only reach about 50 percent, and the boron-10 cannot be put into production, so that the abundance difference from the US 95 percent is very far. Other boron carbide produced by the traditional method is boric acid or boron powder with natural abundance (19.78%), has poor radiation protection effect and is generally used as a material for machining. Furthermore, high purity of 99.999% is also important in addition to abundance, and if boron carbide contains silicon, calcium or other impurities, it can have an adverse effect on processing alloy materials, stainless steel, aluminum, etc. with abundant boron-10 carbide. Therefore, it is necessary to develop a method capable of stably producing boron-10 boron carbide products having high abundance and high purity on a large scale.

Disclosure of Invention

The invention aims to provide a method for preparing high-abundance boron 10-boron carbide, which solves the problem that a method for simultaneously preparing high-abundance and high-purity boron 10-boron carbide products is lacked in the prior art.

In order to achieve the above object, the present invention provides a method for preparing boron carbide 10 with high abundance, comprising the steps of:

s1: preparing boron trifluoride by taking hydrogen fluoride and boric acid as raw materials in a sulfur trioxide atmosphere;

s2: collecting boron trifluoride gas generated in the reaction in the S1, and removing impurities through three-stage rectification to obtain purified boron trifluoride gas;

s3: carrying out complexation reaction by using the boron trifluoride gas purified in the S2 and diethylene glycol dimethyl ether as raw materials, and then decomplexing a complex to obtain boron-10 boron trifluoride gas enriched with boron-10;

s4: preparing boron-10 boric acid enriched with boron-10 by using the boron-10 trifluoride gas enriched with boron-10 in S3 and water as raw materials;

s5: preparing boron-10 boric acid powder by using the boron-10 boric acid obtained in the S4 as a raw material;

s6: and (3) taking the boron-10 boric acid powder obtained in the step (S5) and carbon powder as raw materials, and carrying out reduction reaction in a high-temperature electric furnace to obtain boron-10 boron carbide.

Further, in S6, the abundance ratio of the prepared boron-10 boron carbide is more than or equal to 96%, and the purity is more than or equal to 99.999%.

Further, in the S1, the molar ratio of the raw material components is HF to H₃BO₃:SO₃＝(1-3):(1-3):(2-6)。

Further, in the S1, the molar ratio of the raw material components is: HF: H₃BO₃:SO₃＝1:1:2。

Further, in the S1, the reaction temperature of the hydrogen fluoride and the boric acid is 80-99 ℃.

Further, in S2, the process of removing impurities from the boron trifluoride gas by three-stage rectification specifically includes: the first stage of rectification is light component removal rectification, and the rectification temperature is-10 ℃ to-20 ℃; the second-stage rectification is the heavy component removal rectification, and the rectification temperature is-12 to-22 ℃; the third stage of rectification is carried out in a rectifying tower, the temperature of the bottom of the rectifying tower is-12 to-15 ℃, the temperature of the top of the rectifying tower is-15 to-25 ℃, and the purity of boron trifluoride extracted from a measuring line of the rectifying tower is more than or equal to 99.999 percent.

Further, in the S3, the molar ratio of the raw material components is: boron trifluoride: diethylene glycol dimethyl ether is 1: 30-50; the temperature of the complex reaction is 15-40 ℃; the temperature of the decomplexation reaction is 120-180 ℃.

Further, in the S3, the complexing reaction between boron trifluoride gas and diethylene glycol dimethyl ether and the decomplexing reaction of the complex are carried out for a plurality of times, and the complexing-decomplexing cycle reaction is carried out for 150 times, so that the abundance of the boron-10 boron trifluoride gas enriched with boron-10 is more than or equal to 96%.

Further, in the step S5, boron-10 boric acid is used as a raw material, and a method of crystallization-purification-recrystallization is used to prepare boron-10 boric acid powder.

Further, in the S6, the molar ratio of the raw material components is: boron-10 boric acid powder and carbon powder with the purity of more than or equal to 99.999 percent are 3-4: 1.

The invention provides a method for preparing high-abundance boron-10 boron carbide, which takes hydrogen fluoride and boric acid as raw materials, adopts a multi-step method to prepare the high-abundance boron-10 boron carbide, and highly purifies the product of each step, so that the abundance of the finally generated boron-10 boron carbide can reach more than 96 percent, the purity can reach 99.999 percent, both the high abundance and the high purity are considered, substantial technical progress is made in the field of radiation-proof materials, the preparation method is simple, and the large-scale production can be enlarged.

Drawings

Fig. 1 is a flow chart of a method for preparing abundant boron 10 boron carbide according to an embodiment of the present invention.

Detailed Description

The method for preparing the abundant boron 10 boron carbide provided by the invention is described in more detail by combining the figures and specific examples. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

Referring to fig. 1, a flow chart of a method for preparing abundant boron 10 boron carbide according to the present invention specifically includes the following steps:

s1: preparing boron trifluoride by taking hydrogen fluoride and boric acid as raw materials in a sulfur trioxide atmosphere; wherein the molar ratio of the raw material components is HF to H₃BO₃:SO₃(1-3) - (2-6), preferably, the molar ratio of each component is HF: H₃BO₃:SO₃1:1: 2. In the reaction of this step, the reaction temperature of hydrogen fluoride and boric acid may be set to 80 to 99 c, preferably 85 to 95 c, and the products of the reaction are boron trifluoride and water, which is absorbed by sulfur trioxide in a sulfur trioxide atmosphere to sulfuric acid.

S2: collecting boron trifluoride gas generated in the reaction in the S1, and removing impurities through three-stage rectification to obtain purified boron trifluoride gas; the process of removing impurities by three-stage rectification specifically comprises the following steps: the first stage of rectification is light component removal rectification, namely removing light component impurities such as nitrogen and oxygen in boron trifluoride gas, wherein the rectification temperature is-10 ℃ to-20 ℃; the second-stage rectification is heavy-weight-removing rectification, namely impurities heavier than boron trifluoride, such as calcium, silicon, sulfur-containing compounds and the like, are removed, and light components obtained by rectification are collected, wherein the rectification temperature is-12 to-22 ℃; the third stage of rectification is carried out in a rectifying tower, the temperature of the bottom of the rectifying tower is-12 to-15 ℃, the temperature of the top of the rectifying tower is-15 to-25 ℃, trace elements such as silicon tetrafluoride and the like are further removed, and the purity of boron trifluoride extracted from a measuring line of the rectifying tower is more than or equal to 99.999 percent.

S3: carrying out complexation reaction by using the boron trifluoride gas purified in the S2 and diethylene glycol dimethyl ether as raw materials, and then decomplexing a complex to obtain boron-10 boron trifluoride gas enriched with boron-10; wherein the molar ratio of the raw material components is boron trifluoride: diethylene glycol dimethyl ether is 1: 30-50; the temperature of the complexation reaction is 15-40 ℃. Preferably 20-30 ℃; the temperature of the decomplexation reaction is 120-180 ℃, and preferably 130-160 ℃. As the proton numbers of the boron-10 and the boron 11 are the same and the neutron numbers are different, the selectivity of the complex formed by the boron-10 and the diethylene glycol dimethyl ether is slightly larger than that of the boron 11, so that the boron-10 can be enriched in the complex, the abundance of the obtained boron-10 can be improved after the complex is decomplexed, in order to ensure that the abundance of the finally generated boron-10 boron trifluoride gas is high enough, the complexation reaction between the boron trifluoride gas and the diethylene glycol dimethyl ether and the decomplexation reaction of the complex are carried out for multiple times, and the frequency of the complexation-decomplexation cycle reaction is preferably 120-150 times, so that the abundance of the obtained boron-10 boron trifluoride gas can be ensured to be more than or equal to 96.

S4: preparing boron-10 boric acid enriched with boron-10 by using the boron-10 trifluoride gas enriched with boron-10 in S3 and water as raw materials;

s5: preparing boron-10 boric acid powder by using the boron-10 boric acid obtained in the S4 as a raw material; the preparation method can adopt a crystallization-purification-recrystallization method to obtain high-purity boron-10 boric acid powder.

S6: and (3) taking the boron-10 boric acid powder obtained in the step (S5) and carbon powder as raw materials, and carrying out reduction reaction in a high-temperature electric furnace to obtain boron-10 boron carbide. Wherein the molar ratio of the raw material components is as follows: boron-10 boric acid powder, namely 3-4:1 carbon powder, preferably 4:1, wherein the purity of the carbon powder is more than or equal to 99.999 percent, a vacuum arc furnace is adopted as a high-temperature electric furnace, the reaction temperature can be set to 1800-1850 ℃, the reaction vacuum degree is 600-650mm mercury column, and the reaction time is 1-2 hours; the abundance ratio of the finally obtained boron-10 boron carbide is more than or equal to 96 percent, and the purity ratio is more than or equal to 99.999 percent.

For a further understanding of the present invention, preferred embodiments of the present invention will be described below in conjunction with more detailed embodiments to highlight the features and characteristics of a method for preparing abundant boron-10 carbide provided by the present invention. The description is only intended to illustrate the features and advantages of the method of the invention, and not to limit the scope of protection of the invention. In the following examples, water is understood to be distilled water of high purity, unless otherwise specified.