A boron-rich 10 Method for producing boron carbide with adjustable b content

Abstract

The application relates to the technical field of boron carbide material preparation, in particular to a boron carbide preparation method with adjustable B content. 10 The method comprises the following steps: S1, purifying mixed boron trifluoride gas; S2, introducing the high-purity deionized water to perform a hydrolysis reaction; S3, mixing, dispersing, ball milling and drying treatment with high-purity graphite powder to obtain boron-carbon composite precursor powder; S4, performing a segmented pre-burning treatment to obtain a pre-reaction boron-carbon composite powder; S5, performing carbon thermal reduction sintering to obtain a boron carbide sintering intermediate with rich B; S6, performing crushing, airflow pulverization and grading screening to obtain a boron carbide powder with rich B. 10 The method comprises the following steps: S1, purifying mixed boron trifluor 10 ide gas; S2, introducing the high-purity deionized water to perform a hydrolys 10 is reaction; S3, mixing, dispersing, ball milling and drying treatment with high-purity 10 graphite powder to obtain boron-carbon composite precursor powder; S4, performing a segmented pre-burn 10 ing treatment to obtain a pre-reaction boron-carbon composite powder; S5, performing carbon thermal reduction sintering to obtain a boron carbide sintering intermediate with rich B; and S6, performing crushing, airflow pulverization and grading screening to obtain a boron carbide powder with rich B. The application realizes the preparation of the boron carbide product with rich B by adjusting the boron source abundance through the proportioning of the boron trifluoride gas sources with different abundances, combining the acid preparation through hydrolysis, the boron-carbon compounding, the segmented pre-burning, the vacuum carbon thermal reduction and the powder grading detection process, and adjusting the B content, the impurity content and the particle size distribution of the boron carbide product.

Description

Technical Field

[0001] This invention relates to the field of boron carbide material preparation technology, and particularly to a boron carbide-rich material... 10 A method for preparing boron carbide with adjustable boron content. Background Technology

[0002] Boron carbide possesses characteristics such as high hardness, low density, high temperature resistance, corrosion resistance, and strong neutron absorption capacity, making it an important inorganic non-metallic material in nuclear reactor control materials, neutron shielding materials, special ceramics, and wear-resistant structural components. Among these, 10 Bo isotopes have a high thermal neutron absorption cross section, and in natural boron... 10 The abundance of boron is typically around 19.9%, and it is commonly used in the nuclear industry. 10 Boron carbide (B) utilizes its neutron absorption properties to enable reactor power regulation and shutdown control; while boron carbide, due to its high melting point, high hardness, low secondary gamma radiation, and ease of subsequent disposal, has been widely used as a neutron absorbing material. With the increasing demands for neutron absorption performance and material purity in nuclear-grade control materials, shielding materials, and high-end ceramic components, neutron-rich... 10 Boron carbide (B) 10 B abundance, impurity content, free boron / free carbon control, and batch stability are important factors affecting its application performance.

[0003] Existing wealth 10 The preparation process of boron carbide typically involves a carbothermic reduction reaction between a natural boric acid, boron oxide, or a boron source enriched to a fixed abundance and a carbon source. 10 The boron content is primarily determined by the abundance of the boron source itself, making it difficult to controllably adjust over a wide range to meet different application requirements. Furthermore, traditional boron-carbon mixing and high-temperature reduction processes are prone to problems such as uneven boron-carbon dispersion, residual water and oxygen-containing components, B2O3 volatilization loss, and excessively high levels of free boron or free carbon, resulting in insufficient purity, abundance consistency, and particle size distribution stability of the finished product. This is especially true for nuclear-grade boron-rich materials. 10 For boron carbide products, relying solely on fixed-abundance boric acid for direct carbon sintering makes it difficult to achieve the desired balance. 10 Adjustable boron abundance, controlled boron loss, controlled impurity content, and improved post-treatment powder parameters. Therefore, it is necessary to propose a method for enriching... 10 A method for preparing boron carbide with adjustable boron content to solve the problem of boron enrichment 10 Boron carbide products suffer from problems such as inflexible abundance adjustment, significant boron loss during the reaction process, and insufficient stability in product quality. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides a rich 10 A method for preparing boron carbide with adjustable boron content.

[0005] A kind of wealth 10A method for preparing boron carbide with adjustable boron content includes the following steps:

[0006] S1: Based on the target of the boron carbide product to be prepared 10 B abundance, select at least two. 10 Boron trifluoride gas sources with different abundances were mixed in a specific ratio, and the mixed boron trifluoride gas was purified to obtain boron trifluoride gas enriched with abundance calibration.

[0007] S2: The abundance-calibrated boron trifluoride gas obtained in S1 is introduced into high-purity deionized water for hydrolysis to obtain rich... 10 B boric acid hydrolysate; and for rich boric acid hydrolysate; 10 The boric acid hydrolysate was subjected to crystallization, solid-liquid separation and drying to obtain boric acid powder with abundance calibration.

[0008] S3: The boric acid powder obtained from S2 with abundance calibration enrichment was used as a boron source and mixed with high-purity graphite powder, dispersed, ball-milled and dried to obtain boron-carbon composite precursor powder.

[0009] S4: The boron-carbon composite precursor powder obtained in S3 is placed in an inert atmosphere for segmented pre-calcination to obtain pre-calcined boron-carbon composite powder; and the pre-calcined boron-carbon composite powder is crushed and sieved to obtain pre-reacted boron-carbon composite powder.

[0010] S5: The pre-reacted boron-carbon composite powder obtained in S4 is placed in a vacuum sintering environment and subjected to carbothermic reduction sintering under high-purity inert gas protection to obtain a rich... 10 Boron carbide sintering intermediate;

[0011] S6: The richness obtained from S5 10 The boron carbide sintering intermediate was crushed, air-jet milled, and graded and sieved to obtain a rich boron carbide sintering intermediate. 10 Boron carbide powder; and for rich boron carbide powder; 10 Boron carbide powder is subjected to 10 B abundance and impurity content were detected, and after passing the tests, the product was considered rich. 10 Boron carbide products with adjustable boron content.

[0012] Optionally, S1 specifically includes:

[0013] S11: Determine the target for the boron carbide product to be prepared. 10 B abundance The target 10 B abundance The content is 70%–97%, and at least two types are selected from the boron trifluoride gas source group. 10 Boron trifluoride gas sources with different abundances are used as the gas sources to be mixed. The boron trifluoride gas source group includes... 10 A first boron trifluoride gas source with a boron abundance of 70%–80%,10 A boron trifluoride gas source with a boron abundance of 80%–90% and 10 A third boron trifluoride gas source with a boron abundance of 90%–97%;

[0014] S12: Obtain the gas sources to be mixed respectively. 10 B Measured Abundance And according to the target 10 B abundance and each gas source to be mixed 10 B Measured Abundance Determine the intake flow rate of each gas source to be mixed. The intake flow rates of each gas source to be mixed satisfy: ,in, The quantity of gas sources to be mixed, and The single-path intake flow rate of each gas source to be mixed The flow rate is 0.05–5 L / min, and the total mixed flow rate is 0.2–10 L / min;

[0015] S13: Each gas source to be mixed is introduced into the corresponding drying and filtration branch for pretreatment. The drying and filtration branch includes a molecular sieve drying column and a microporous filter. The drying temperature is 20-35℃, and the dew point of the gas after drying is not higher than -40℃. The filtration accuracy of the microporous filter is 0.01-0.1μm, and the corresponding pretreated boron trifluoride gas is obtained.

[0016] S14: The pretreated boron trifluoride gases obtained in S13 are respectively fed into the gas mixing tank via a mass flow controller, according to the inlet flow rate determined in S12. Continuous gas mixing is performed, with the pressure inside the gas mixing tank controlled at 0.02–0.15 MPa, the mixing temperature controlled at 15–35 °C, and the mixing time at 20–60 min, to obtain the mixed boron trifluoride gas.

[0017] Optionally, S1 further includes:

[0018] S15: The mixed boron trifluoride gas obtained in S14 is introduced into a complexation absorption tank to react with the ethylene glycol dimethyl ether complexing agent. The molar ratio of the ethylene glycol dimethyl ether complexing agent to the boron trifluoride in the mixed boron trifluoride gas is 1.05:1 to 1.30:1. The complexation absorption temperature is 15 to 30°C, the complexation absorption pressure is 0.03 to 0.20 MPa, and the complexation absorption time is 1 to 4 h to obtain a boron trifluoride complex solution.

[0019] S16: The boron trifluoride complex obtained in S15 is transferred to the decomposition and purification unit for decomposition at a temperature of 75–95°C, a pressure of 0.01–0.08 MPa, and a time of 0.5–3 h, releasing decomposition boron trifluoride gas. The decomposition boron trifluoride gas is then passed sequentially through a cold trap and a filter. The cold trap temperature is -50–-20°C, and the filter accuracy is 0.01–0.05 μm, to obtain purified boron trifluoride gas.

[0020] S17: The purified boron trifluoride gas obtained in S16 is subjected to... 10 B abundance and purity detection, when purifying boron trifluoride gas 10 B Measured abundance and target 10 B abundance When the deviation is no greater than 0.3 percentage points and the purity of boron trifluoride is no less than 99.5%, the purified boron trifluoride gas is used as the abundance calibration enrichment gas for boron trifluoride.

[0021] Optionally, S2 specifically includes:

[0022] S21: Add high-purity deionized water with a resistivity of not less than 18 MΩ·cm to the hydrolysis reactor, control the initial temperature of the high-purity deionized water to be 5-25℃, and form the water phase to be absorbed under stirring conditions of 80-250 r / min;

[0023] S22: The abundance-calibrated boron trifluoride gas obtained in S1 is introduced into the aqueous phase to be absorbed obtained in S21 through a fluorine-resistant gas distributor. The inlet flow rate is controlled at 0.03–0.50 L / min, the hydrolysis reaction temperature is 10–35℃, the hydrolysis reaction pressure is 0.01–0.10 MPa, and the reaction time is 0.5–4 h to obtain the initial enriched... 10 B boric acid hydrolysate;

[0024] S23: The initial richness obtained from S22 10 The boric acid hydrolysate was stirred and matured for another 20–60 minutes, with the pH adjusted to 2.8–4.2. It was then filtered through a membrane with a pore size of 0.1–0.45 μm to obtain a solution rich in boric acid. 10 B boric acid hydrolysate;

[0025] S24: The richness obtained from S23 10 The boric acid hydrolysate was concentrated under reduced pressure at a temperature of 45–70 °C and a vacuum degree of -0.06–-0.095 MPa until the boric acid mass concentration in the solution reached 20%–45%, yielding a boric acid-rich solution. 10 B. Boric acid concentrate.

[0026] Optionally, S2 further includes:

[0027] S25: The richness obtained from S24 10 The concentrated boric acid solution was cooled to 2–12°C for crystallization at a cooling rate of 0.2–1.5°C / min for 2–8 hours to obtain a rich boric acid solution. 10 Boric acid crystallizing slurry; for rich boric acid crystals 10 The boric acid crystal slurry was filtered to obtain a wet-state rich boric acid crystal. 10 B-boronic acid crystals;

[0028] S26: The wet enrichment obtained from S25 is processed with high-purity deionized water at 5-15℃. 10 Boric acid crystals were washed 1–3 times and dried at 50–80°C and a vacuum of -0.08–-0.098 MPa for 2–8 hours. They were then passed through an 80–200 mesh sieve to obtain boric acid powder with enrichment calibrated by abundance.

[0029] Optionally, S3 specifically includes:

[0030] S31: Take the abundance-calibrated boric acid powder obtained in S2 as the boron source, and take high-purity graphite powder with a purity of not less than 99.99% and a D50 of 0.5 to 3 μm as the carbon source; weigh the abundance-calibrated boric acid powder and high-purity graphite powder according to the molar ratio of boron to carbon of 4:0.98 to 1.05 to obtain the boron-carbon feedstock composition.

[0031] S32: Add the boron-carbon ingredient components obtained in S31 into a mixing container, and add anhydrous ethanol as a dispersion medium. The amount of anhydrous ethanol added is 40% to 120% of the total mass of the boron-carbon ingredient components. Premix at a stirring speed of 100 to 300 r / min for 20 to 60 min to obtain boron-carbon premixed slurry.

[0032] S33: The boron-carbon premixed slurry obtained in S32 is transferred into a ball mill jar for dispersion ball milling. Both the ball mill jar and the grinding balls are made of zirconium oxide. The ball-to-material mass ratio is 3-8:1, the ball milling speed is 200-450 r / min, and the ball milling time is 4-12 h to obtain the boron-carbon dispersion slurry.

[0033] S34: The boron-carbon dispersion slurry is subjected to solid-liquid transfer and preliminary evaporation treatment at 60-90℃ to reduce the anhydrous ethanol content in the boron-carbon dispersion slurry to 5wt%-15wt%, thereby obtaining wet boron-carbon composite powder.

[0034] S35: Place the wet boron-carbon composite powder in a vacuum drying equipment and dry it for 3 to 8 hours at 80 to 120°C and a vacuum degree of -0.08 to -0.098 MPa to obtain dry boron-carbon composite powder; then grind the dry boron-carbon composite powder and pass it through an 80 to 200 mesh sieve to obtain boron-carbon composite precursor powder.

[0035] Optionally, S4 specifically includes:

[0036] S41: Spread the boron-carbon composite precursor powder obtained in S3 in an alumina crucible, with the thickness of the spread material controlled at 5-30 mm, and place the alumina crucible containing the boron-carbon composite precursor powder into an inert atmosphere pre-calcination furnace.

[0037] S42: High-purity argon or high-purity nitrogen is introduced into the inert atmosphere pre-burning furnace for replacement. The purity of the inert gas is not less than 99.99%, and the replacement time is 20 to 60 minutes. After replacement, the inert gas flow rate is maintained at 0.2 to 2.0 L / min.

[0038] S43: The inert atmosphere pre-calcination furnace is heated to 300-450℃ at a heating rate of 2-5℃ / min and held for 1.5-3h to obtain low-temperature pre-calcined boron-carbon powder.

[0039] S44: The low-temperature pre-calcined boron-carbon powder is further heated to 650-780℃ at a heating rate of 2-6℃ / min and held for 1.5-3h to obtain pre-calcined boron-carbon composite powder;

[0040] S45: After the pre-burned boron-carbon composite powder obtained in S44 is cooled to below 80°C in the furnace, it is taken out and crushed. The particle size of the crushed powder is controlled to be no greater than 2mm.

[0041] S46: The pre-burned boron-carbon composite powder after crushing S45 is sieved and collected sequentially. The sieve mesh size is 80-200 mesh, and the material passing through the sieve is taken as the pre-reacted boron-carbon composite powder.

[0042] Optionally, S5 specifically includes:

[0043] S51: Load the pre-reacted boron-carbon composite powder into a graphite crucible, control the thickness of the material to be 10-50mm, and place the graphite crucible containing the pre-reacted boron-carbon composite powder into a vacuum sintering furnace.

[0044] S52: Vacuum the vacuum sintering furnace to achieve a vacuum level of 1×10⁻⁶. -2 ~5×10 -3 Pa, and heated to 600-900℃ at a heating rate of 3-8℃ / min, and held for 20-60min to obtain vacuum pre-desorbed powder;

[0045] S53: High-purity argon or high-purity nitrogen is introduced into the vacuum sintering furnace. The purity of the high-purity argon or high-purity nitrogen is not less than 99.999%. The gas pressure inside the furnace is controlled at 0.02 to 0.12 MPa, and the gas flow rate is controlled at 0.2 to 2.0 L / min.

[0046] S54: The vacuum pre-desorbed powder obtained in S52 is heated to 1200-1450℃ under the protection of high-purity inert gas in S53, with a heating rate of 5-10℃ / min, and held for 20-60min to obtain the preliminary reduced boron carbon powder.

[0047] S55: The preliminarily reduced boron-carbon powder obtained in S54 is further heated to 1750–1920℃ at a heating rate of 3–8℃ / min and held at that temperature for 30–120 min to complete the carbothermic reduction sintering and obtain a rich boron-carbon powder. 10 B. Boron carbide sintering material;

[0048] S56: The richness obtained from S55 10 After the boron carbide sintering material was cooled to below 300°C under high-purity inert gas protection, the gas supply was stopped, and it was cooled to below 80°C with the furnace. The resulting product was rich in boron carbide. 10 B. Boron carbide sintering intermediate.

[0049] Optionally, S6 specifically includes:

[0050] S61: The richness obtained from S5 10 After the boron carbide sintering intermediate is cooled to room temperature, it is coarsely crushed to a particle size of no more than 5 mm to obtain a rich boron carbide intermediate. 10 B. Boron carbide coarse crushed material;

[0051] S62: The richness obtained from S61 10 Boron carbide coarse crushed material (B) is ground and crushed. The grinding equipment is lined with boron carbide, silicon nitride, or zirconium oxide. The grinding time is 0.5–3 hours. After grinding, the material is passed through a 40–100 mesh sieve to obtain a rich... 10 B. Boron carbide pre-crushed material;

[0052] S63: The richness obtained from S62 10 Boron carbide pre-crushed material is fed into an air jet mill for air jet milling. The milling medium is high-purity nitrogen or high-purity argon gas with a purity of not less than 99.999%. The milling pressure is 0.4–0.9 MPa, the feed rate is 0.2–2 kg / h, and the classifier speed is 3000–9000 r / min, to obtain a material rich in boron carbide. 10 Boron carbide refined powder;

[0053] S64: The richness obtained from S63 10 Boron carbide fine powder was graded and sieved at a mesh size of 300–1000 mesh. The undersize powder with a D50 of 50–200 nm and a D90 not exceeding 500 nm was collected to obtain a rich powder. 10 B. Boron carbide powder.

[0054] Optionally, S6 specifically includes:

[0055] S65: From wealth10 A sample of 5–20 g of boron carbide powder was taken and dried at 80–120 °C and a vacuum of -0.08–-0.098 MPa for 1–3 h to obtain the boron-rich sample to be tested. 10 B boron carbide sample;

[0056] S66: Treatment of rich substances in the test 10 Boron carbide sample B was subjected to 10 B abundance detection, free boron content detection, free carbon content detection, oxygen content detection, and metal impurity content detection;

[0057] S67: When detected by S66 10 B Measured abundance and target 10 The abundance deviation of boron is no greater than 0.3 percentage points, the free boron content is no greater than 0.5 wt%, the free carbon content is no greater than 0.3 wt%, the oxygen content is no greater than 0.1 wt%, the total amount of metallic impurities is no greater than 100 ppm, and it is rich in... 10 When the purity of boron carbide powder is not less than 99.9%, the corresponding batch of enriched... 10 Boron carbide powder as a rich 10 Boron carbide products with adjustable boron content.

[0058] The beneficial effects of this invention are:

[0059] This invention, by using at least two 10 Using boron trifluoride gas sources with varying abundances as raw materials, and according to the target... 10 The boron carbide (B) abundance is subjected to proportioning, mixing, and purification, followed by hydrolysis to prepare abundance-calibrated enriched boric acid powder, which is then used in subsequent boron carbide products. 10 The boron content can be controlled from the feedstock gas source. Compared to directly preparing boron carbide using fixed-abundance boric acid or natural boron sources, this method allows for the preparation of boron-rich boron carbide according to different application requirements. 10 Boron carbide products with adjustable boron content solve the problems associated with existing processes. 10 The problem of B abundance relying on a single boron source and lacking sufficient adjustment flexibility.

[0060] This invention provides a method for mixing, dispersing, ball milling, and drying boric acid powder enriched with boric acid based on abundance calibration with high-purity graphite powder to form a boron-carbon composite precursor powder. Further processing involves staged pre-calcination in an inert atmosphere, carbothermic reduction sintering under vacuum, and subsequent crushing, airflow milling, and grading sieving to obtain a boron-carbon composite precursor powder. 10 B. Boron carbide powder; This process chain enables the boron and carbon sources to fully combine before the reaction, and reduces the influence of water and oxygen-containing impurities on the high-temperature reduction process through pre-calcination and vacuum sintering. This facilitates the control of free boron, free carbon, oxygen content, and metal impurity content, thereby improving the enrichment... 10The purity, particle size consistency, and batch stability of boron carbide products. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This is a schematic diagram of the boron carbide preparation method according to an embodiment of the present invention. Detailed Implementation

[0063] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0064] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0065] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0066] Example 1

[0067] like Figure 1 As shown, a rich 10 A method for preparing boron carbide with adjustable boron content includes the following steps:

[0068] S1: Based on the target of the boron carbide product to be prepared 10 B abundance, select at least two. 10Boron trifluoride gas sources with different abundances were mixed in a specific ratio, and the mixed boron trifluoride gas was purified to obtain boron trifluoride gas enriched with abundance calibration.

[0069] S2: The abundance-calibrated boron trifluoride gas obtained in S1 is introduced into high-purity deionized water for hydrolysis to obtain rich... 10 B boric acid hydrolysate; and for rich boric acid hydrolysate; 10 The boric acid hydrolysate was subjected to crystallization, solid-liquid separation and drying to obtain boric acid powder with abundance calibration.

[0070] S3: The boric acid powder obtained from S2 with abundance calibration enrichment was used as a boron source and mixed with high-purity graphite powder, dispersed, ball-milled and dried to obtain boron-carbon composite precursor powder.

[0071] S4: The boron-carbon composite precursor powder obtained in S3 is placed in an inert atmosphere for segmented pre-calcination to obtain pre-calcined boron-carbon composite powder; and the pre-calcined boron-carbon composite powder is crushed and sieved to obtain pre-reacted boron-carbon composite powder.

[0072] S5: The pre-reacted boron-carbon composite powder obtained in S4 is placed in a vacuum sintering environment and subjected to carbothermic reduction sintering under high-purity inert gas protection to obtain a rich... 10 Boron carbide sintering intermediate;

[0073] S6: The richness obtained from S5 10 The boron carbide sintering intermediate was crushed, air-jet milled, and graded and sieved to obtain a rich boron carbide sintering intermediate. 10 Boron carbide powder; and for rich boron carbide powder; 10 Boron carbide powder is subjected to 10 B abundance and impurity content were detected, and after passing the tests, the product was considered rich. 10 Boron carbide products with adjustable boron content. Specifically:

[0074] S1: Determine the target product to be prepared (boron carbide product) 10 The abundance of B (Ft) was 85.0%. [Selection] 10 B is a boron trifluoride gas source with a measured abundance of 80.0% and 10 Using boron trifluoride gas with a measured abundance of 90.0% as the gas source to be mixed, the two inlet flow rates Q1 and Q2 were set to 2.5 L / min and 2.5 L / min respectively, with a total mixing flow rate of 5.0 L / min, according to the formula... The calculated mixed abundance was 85.0%. Two streams of boron trifluoride gas were pretreated by passing them through a molecular sieve drying column and a microporous filter, respectively. The drying temperature was controlled at 27℃, the dew point of the dried gas was -50℃, and the filtration accuracy of the microporous filter was 0.05μm. The pretreated boron trifluoride gas was then fed into a gas mixing tank via a mass flow controller. The pressure inside the gas mixing tank was controlled at 0.08MPa, the mixing temperature at 25℃, and the mixing time at 40min, resulting in a mixed boron trifluoride gas. This mixed boron trifluoride gas was then passed into a complexation absorption tank and reacted with an ethylene glycol dimethyl ether complexing agent. The molar ratio of the ethylene glycol dimethyl ether complexing agent to boron trifluoride was 1.18:1, the complexation absorption temperature was 22℃, the complexation absorption pressure was 0.10MPa, and the complexation absorption time was 2.5h, yielding a boron trifluoride complex solution. The boron trifluoride complex solution was then transferred to a decomplexing purification unit. The decomplexing temperature was 85℃, the decomplexing pressure was 0.045MPa, and the decomplexing time was 1.5h, releasing decomplexed boron trifluoride gas. This gas was then passed sequentially through a -35℃ cold trap and a filter with a filtration accuracy of 0.03μm to obtain purified boron trifluoride gas. Testing revealed that the purified boron trifluoride gas... 10 The measured abundance of B was 85.1%, which is consistent with the target. 10 The abundance deviation of boron trifluoride was 0.1 percentage points, and the purity of boron trifluoride was 99.7%. It was used as the abundance calibration to enrich boron trifluoride gas.

[0075] S2: High-purity deionized water with a resistivity of 18.2 MΩ·cm was added to the hydrolysis reactor. The initial temperature of the high-purity deionized water was controlled at 15℃, and the aqueous phase to be absorbed was formed under stirring at 160 r / min. The abundance-calibrated boron trifluoride gas obtained in S1 was introduced into the aqueous phase to be absorbed through a fluorine-resistant gas distributor. The inlet flow rate was controlled at 0.25 L / min. The hydrolysis reaction temperature was 22℃, the hydrolysis reaction pressure was 0.05 MPa, and the reaction time was 2 h, resulting in an initial enriched... 10 B boric acid hydrolysate. For initially rich 10 The boric acid hydrolysate was stirred and matured for another 40 minutes, and the pH of the solution was controlled to 3.5. It was then filtered through a 0.22 μm pore size membrane to obtain a solution rich in boric acid. 10 B boric acid hydrolysate. (The rich...) 10 The boric acid hydrolysate was concentrated under reduced pressure at 58℃ and a vacuum of -0.080 MPa until the boric acid mass concentration in the solution reached 32%, yielding a solution rich in boric acid. 10 B boric acid concentrate. (The rich...) 10 The concentrated boric acid solution was cooled to 7°C at a cooling rate of 0.8°C / min and crystallized for 5 hours to obtain a rich solution. 10 Boric acid crystallizing slurry; for rich boric acid crystals 10 The boric acid crystal slurry was filtered to obtain a wet-state rich boric acid crystal.10 Boric acid crystals. The wet state rich in boronic acid was treated with high-purity deionized water at 10℃. 10 Boric acid crystals were washed twice and dried at 65°C and a vacuum of -0.090 MPa for 5 hours. They were then passed through a 140-mesh sieve to obtain boric acid powder with enrichment calibrated by abundance.

[0076] S3: Using the abundance-calibrated enriched boric acid powder obtained in S2 as the boron source, and high-purity graphite powder with a purity of 99.995% and a D50 of 1.5 μm as the carbon source, weigh the abundance-calibrated enriched boric acid powder and high-purity graphite powder according to a boron to carbon molar ratio of 4:1.02 to obtain the boron-carbon feedstock. Add the boron-carbon feedstock to a mixing container and add anhydrous ethanol as the dispersion medium. The amount of anhydrous ethanol added is 80% of the total mass of the boron-carbon feedstock. Premix at a stirring speed of 200 r / min for 40 min to obtain a boron-carbon premixed slurry. Transfer the boron-carbon premixed slurry to a zirconia ball mill jar and disperse it using zirconia grinding balls at a ball-to-powder mass ratio of 5:1, a ball milling speed of 325 r / min, and a ball milling time of 8 h to obtain a boron-carbon dispersion slurry. The boron-carbon dispersion slurry was subjected to preliminary evaporation treatment at 75℃ to reduce the anhydrous ethanol content to 10wt%, yielding a wet boron-carbon composite powder. The wet boron-carbon composite powder was then placed in a vacuum drying apparatus and dried at 100℃ and a vacuum of -0.090MPa for 5 hours to obtain a dry boron-carbon composite powder. Subsequently, the dry boron-carbon composite powder was ground and passed through a 140-mesh sieve to obtain the boron-carbon composite precursor powder.

[0077] S4: The boron-carbon composite precursor powder obtained in S3 is spread evenly in an alumina crucible with a thickness controlled at 18 mm. The alumina crucible is then placed in an inert atmosphere pre-calcination furnace. High-purity argon gas (99.995%) is introduced into the inert atmosphere pre-calcination furnace for purging for 40 min. After purging, the argon gas flow rate is maintained at 1.0 L / min. The pre-calcination furnace is heated to 375℃ at a heating rate of 3.5℃ / min and held for 2.2 h to obtain low-temperature pre-calcined boron-carbon powder. Then, the temperature is increased to 720℃ at a heating rate of 4℃ / min and held for 2.2 h to obtain pre-calcined boron-carbon composite powder. The pre-calcined boron-carbon composite powder is cooled to below 80℃ in the furnace and then removed for crushing. The particle size of the crushed powder is controlled to be no greater than 1 mm. Subsequently, it is sieved with a sieve mesh of 140 mesh, and the undersize material is taken as the pre-reacted boron-carbon composite powder.

[0078] S5: The pre-reacted boron-carbon composite powder obtained in S4 is loaded into a graphite crucible, with a thickness controlled at 30 mm. The graphite crucible is then placed into a vacuum sintering furnace. The vacuum sintering furnace is evacuated to a vacuum level of 7 × 10⁻⁶. -3The temperature was increased to 750℃ at a rate of 5℃ / min and held for 40 min to obtain vacuum pre-desorbed powder. Then, high-purity argon gas (99.9995%) was introduced into the vacuum sintering furnace, with the furnace pressure controlled at 0.07 MPa and the gas flow rate at 1.0 L / min. The vacuum pre-desorbed powder was then heated to 1320℃ at a rate of 7℃ / min under high-purity argon protection and held for 40 min to obtain pre-reduced boron-carbon powder. The temperature was then further increased to 1840℃ at a rate of 5℃ / min and held for 75 min to complete carbothermic reduction sintering, yielding a rich boron-carbon powder. 10 B. Boron carbide sintering material. (The text abruptly ends here, likely due to an incomplete sentence 10 After the boron carbide sinter was cooled to below 300°C under high-purity argon protection, the gas supply was stopped, and the furnace was cooled to below 80°C. The resulting product was then enriched with high-purity argon. 10 B. Boron carbide sintering intermediate.

[0079] S6: The richness obtained in S5 10 After the boron carbide sintering intermediate is cooled to room temperature, it is coarsely crushed to a particle size of no more than 3 mm to obtain a rich boron carbide intermediate. 10 B. Boron carbide coarse crushed material. For rich... 10 Boron carbide coarse crushed material (B) was ground and crushed using a grinding equipment lined with silicon nitride. The grinding time was 1.5 hours, and the crushed material was then passed through an 80-mesh sieve to obtain a rich... 10 B. Boron carbide pre-crushed material. (The text abruptly ends here, likely due to an incomplete sentence or missing information.) 10 Boron carbide pre-crushed material is fed into an air jet mill. The grinding medium is high-purity nitrogen gas with a purity of 99.9995%. The grinding pressure is 0.65 MPa, the feed rate is 1.0 kg / h, and the classifier speed is 6000 r / min, resulting in a material rich in boron carbide. 10 Boron carbide refined powder. For rich... 10 Boron carbide fine powder was graded and sieved at a mesh size of 600 mesh. The undersize powder with a D50 of 120 nm and a D90 of 350 nm was collected to obtain a rich powder. 10 Boron carbide powder (B). A 10g sample was dried at 100℃ under a vacuum of -0.090MPa for 2 hours to obtain the boron-rich powder to be tested. 10 Sample B, boron carbide. Analysis showed that the sample... 10 The measured abundance of B was 85.0%, which is consistent with the target abundance. 10 The abundance deviation of boron was 0 percentage points, the free boron content was 0.18 wt%, the free carbon content was 0.12 wt%, the oxygen content was 0.04 wt%, and the total amount of metallic impurities was 38 ppm, indicating a rich boron content. 10 The boron carbide powder has a purity of 99.95%, and this batch of powder is deemed qualified, yielding a rich... 10 Boron carbide products with adjustable boron content.

[0080] Example 2

[0081] S1: Determine the target product to be prepared (boron carbide product) 10 The abundance of B (Ft) was 72.5%. [Selection] 10 B is a boron trifluoride gas source with a measured abundance of 70.0% and 10 Using boron trifluoride gas with a measured abundance of 80.0% as the gas source to be mixed, the inlet flow rates Q1 and Q2 were set to 0.15 L / min and 0.05 L / min respectively, with a total mixing flow rate of 0.20 L / min. The calculated mixed abundance was 72.5%. Two streams of boron trifluoride gas were separately introduced into the drying and filtration branches. The drying temperature was controlled at 20℃, and the dew point of the dried gas was -40℃. The microfiltration accuracy was 0.01μm, resulting in pretreated boron trifluoride gas. Each pretreated boron trifluoride gas was then fed into a gas mixing tank via a mass flow controller. The pressure inside the gas mixing tank was controlled at 0.02MPa, the mixing temperature at 15℃, and the mixing time at 20min, resulting in mixed boron trifluoride gas. This mixed boron trifluoride gas was then introduced into a complexation absorption tank, where it reacted with an ethylene glycol dimethyl ether complexing agent. The molar ratio of the ethylene glycol dimethyl ether complexing agent to boron trifluoride was 1.05:1. The complexation absorption temperature was 15℃, the complexation absorption pressure was 0.03MPa, and the complexation absorption time was 1h, resulting in a boron trifluoride complex solution. The boron trifluoride complex solution was purified by decomplexing at a temperature of 75℃, a pressure of 0.01 MPa, and a time of 0.5 h. The released decomplexed boron trifluoride gas was then passed sequentially through a -50℃ cold trap and a filter with a filtration precision of 0.01 μm to obtain purified boron trifluoride gas. The purified boron trifluoride gas was tested... 10 The measured abundance of B was 72.4%, which is consistent with the target abundance. 10 The abundance deviation of boron trifluoride was 0.1 percentage points, and the purity of boron trifluoride was 99.5%. It was used as the abundance calibration to enrich boron trifluoride gas.

[0082] S2: High-purity deionized water with a resistivity of 18.0 MΩ·cm was added to the hydrolysis reactor, and the initial temperature was controlled at 5℃. The aqueous phase to be absorbed was formed under stirring at 80 r / min. The abundance-calibrated boron trifluoride gas obtained in S1 was introduced into the aqueous phase to be absorbed through a fluorine-resistant gas distributor. The inlet flow rate was controlled at 0.03 L / min. The hydrolysis reaction temperature was 10℃, the hydrolysis reaction pressure was 0.01 MPa, and the reaction time was 0.5 h, yielding the initial enriched... 10 B boric acid hydrolysate. For initially rich 10 The boric acid hydrolysate was stirred and matured for another 20 minutes, and the pH of the solution was controlled to 2.8. It was then filtered through a 0.10 μm pore size membrane to obtain a solution rich in boric acid. 10 B boric acid hydrolysate. (The rich...) 10The boric acid hydrolysate was concentrated under reduced pressure at 45℃ and a vacuum of -0.060 MPa until the boric acid mass concentration in the solution reached 20%, yielding a boric acid-rich solution. 10 B boric acid concentrate. (The rich...) 10 The concentrated boric acid solution was cooled to 2℃ at a cooling rate of 0.2℃ / min and crystallized for 2 hours to obtain a rich solution. 10 Boric acid crystallizing slurry; for rich boric acid crystals 10 Boric acid crystallization slurry was separated by filtration to obtain wet-state rich boric acid. 10 Boric acid crystals were washed once with high-purity deionized water at 5°C and dried for 2 hours at 50°C and a vacuum of -0.080 MPa. The resulting product was then passed through an 80-mesh sieve to obtain boric acid powder with enrichment calibrated by abundance.

[0083] S3: Using the boric acid powder enriched by abundance calibration obtained in S2 as the boron source, and high-purity graphite powder with a purity of 99.99% and a D50 of 0.5 μm as the carbon source, the raw materials were weighed according to a boron to carbon molar ratio of 4:0.98 to obtain the boron-carbon feedstock. The boron-carbon feedstock was added to a mixing container, and anhydrous ethanol was added as the dispersion medium. The amount of anhydrous ethanol added was 40% of the total mass of the boron-carbon feedstock. Premixing was carried out at a stirring speed of 100 r / min for 20 min to obtain a boron-carbon premixed slurry. The boron-carbon premixed slurry was transferred to a zirconia ball mill jar for dispersion and ball milling. The ball-to-powder mass ratio was 3:1, the ball milling speed was 200 r / min, and the ball milling time was 4 h to obtain a boron-carbon dispersion slurry. The boron-carbon dispersion slurry was subjected to preliminary evaporation treatment at 60℃ to reduce the anhydrous ethanol content to 5 wt%, obtaining a wet boron-carbon composite powder. The wet boron-carbon composite powder was dried at 80℃ and under a vacuum of -0.080MPa for 3 hours to obtain the dried boron-carbon composite powder; then it was ground and passed through an 80-mesh sieve to obtain the boron-carbon composite precursor powder.

[0084] S4: Spread the boron-carbon composite precursor powder obtained in S3 evenly in an alumina crucible, controlling the thickness of the spread to be 5 mm, and place the alumina crucible in an inert atmosphere pre-calcination furnace. Purge the pre-calcination furnace with 99.99% pure nitrogen gas for 20 min, maintaining a nitrogen flow rate of 0.2 L / min after purging. Heat the pre-calcination furnace to 300℃ at a heating rate of 2℃ / min and hold for 1.5 h to obtain low-temperature pre-calcined boron-carbon powder; then heat to 650℃ at a heating rate of 2℃ / min and hold for 1.5 h to obtain pre-calcined boron-carbon composite powder. Cool the pre-calcined boron-carbon composite powder in the furnace to below 80℃, remove it, and crush it to a particle size no greater than 2 mm; then sieve it using an 80-mesh sieve, and take the undersize as the pre-reacted boron-carbon composite powder.

[0085] S5: The pre-reacted boron-carbon composite powder obtained in S4 is loaded into a graphite crucible, with a thickness controlled at 10 mm. The graphite crucible is then placed into a vacuum sintering furnace. The vacuum sintering furnace is evacuated to a vacuum level of 1×10⁻⁶. -2 The temperature was increased to 600℃ at a rate of 3℃ / min and held for 20 min to obtain vacuum pre-desorbed powder. High-purity nitrogen (99.999%) was introduced into the vacuum sintering furnace, with the furnace pressure controlled at 0.02 MPa and the gas flow rate at 0.2 L / min. The vacuum pre-desorbed powder was heated to 1200℃ at a rate of 5℃ / min under high-purity nitrogen protection and held for 20 min to obtain pre-reduced boron-carbon powder. Subsequently, the temperature was increased to 1750℃ at a rate of 3℃ / min and held for 30 min to complete carbothermic reduction sintering, obtaining rich boron-carbon powder. 10 B. Boron carbide sintering material. (The text abruptly ends here, likely due to an incomplete sentence 10 After the boron carbide sinter was cooled to below 300°C under high-purity nitrogen protection, the gas supply was stopped, and the sinter was cooled to below 80°C in the furnace. The resulting product was then enriched with nitrogen. 10 B. Boron carbide sintering intermediate.

[0086] S6: The richness obtained in S5 10 After the boron carbide sintering intermediate is cooled to room temperature, it is coarsely crushed to a particle size of no more than 5 mm to obtain a rich boron carbide intermediate. 10 B. Boron carbide coarse crushed material. For rich... 10 Boron carbide coarse crushed material (B) was ground and crushed using a grinding equipment lined with boron carbide. The grinding time was 0.5 hours. After grinding, the material was passed through a 40-mesh sieve to obtain a rich boron carbide product. 10 B. Boron carbide pre-crushed material. (The text abruptly ends here, likely due to an incomplete sentence or missing information.) 10 Boron carbide pre-crushed material is fed into an air jet mill. The grinding medium is high-purity nitrogen gas with a purity of 99.999%. The grinding pressure is 0.4 MPa, the feed rate is 0.2 kg / h, and the classifier speed is 3000 r / min, resulting in a material rich in... 10 Boron carbide refined powder. For rich... 10 Boron carbide fine powder was subjected to 300-mesh sieving, and the undersize powder with D50 of 50 nm and D90 of 300 nm was collected to obtain a rich powder. 10 Boron carbide powder (B). A 5g sample was dried at 80℃ and a vacuum of -0.080MPa for 1 hour to obtain the boron-rich powder to be tested. 10 Sample B, boron carbide. Analysis showed that the sample... 10 The measured abundance of B was 72.3%, which is consistent with the target abundance. 10 The abundance deviation of boron was 0.2 percentage points, the free boron content was 0.46 wt%, the free carbon content was 0.28 wt%, the oxygen content was 0.09 wt%, the total metal impurities were 92 ppm, and the powder purity was 99.90%. Therefore, this batch of powder was deemed qualified and rich in boron. 10Boron carbide products with adjustable boron content.

[0087] Example 3:

[0088] S1: Determine the target product to be prepared (boron carbide product) 10 The abundance of boron trifluoride (B) was 96.95%. Two sources were selected from the high-abundance boron trifluoride gas source. 10 One of the boron trifluoride gas sources with different abundances is B. 10 The measured abundance of B was 96.9%, and another path 10 The measured abundance of B was 97.0%. The two intake flow rates were set to 5.0 L / min and 5.0 L / min respectively, and the total mixed flow rate was 10.0 L / min. The calculated mixture abundance was 96.95%. Two streams of boron trifluoride gas were separately introduced into a drying and filtration branch. The drying temperature was controlled at 35℃, and the dew point of the dried gas was -60℃. The microfiltration accuracy was 0.10 μm, resulting in pretreated boron trifluoride gas. These two streams of pretreated boron trifluoride gas were then fed into a gas mixing tank via a mass flow controller. The pressure inside the gas mixing tank was controlled at 0.15 MPa, the mixing temperature at 35℃, and the mixing time at 60 min, resulting in mixed boron trifluoride gas. This mixed boron trifluoride gas was then introduced into a complexation absorption tank, where it reacted with an ethylene glycol dimethyl ether complexing agent. The molar ratio of the ethylene glycol dimethyl ether complexing agent to boron trifluoride was 1.30:1. The complexation absorption temperature was 30℃, the complexation absorption pressure was 0.20 MPa, and the complexation absorption time was 4 h, resulting in a boron trifluoride complex solution. The boron trifluoride complex solution was transferred to a decomplexing purification unit. The decomplexing temperature was 95℃, the decomplexing pressure was 0.08MPa, and the decomplexing time was 3 hours, releasing decomplexed boron trifluoride gas. This gas was then passed sequentially through a -20℃ cold trap and a filter with a filtration accuracy of 0.05μm to obtain purified boron trifluoride gas. Testing revealed that the purified boron trifluoride gas... 10 The measured abundance of B was 96.9%, which is consistent with the target. 10 The abundance deviation of boron trifluoride was 0.05 percentage points, and the purity of boron trifluoride was 99.9%. It was used as the abundance calibration to enrich boron trifluoride gas.

[0089] S2: High-purity deionized water with a resistivity of 18.5 MΩ·cm was added to the hydrolysis reactor. The initial temperature of the high-purity deionized water was controlled at 25℃, and the aqueous phase to be absorbed was formed under stirring at 250 r / min. The abundance-calibrated boron trifluoride gas obtained in S1 was introduced into the aqueous phase to be absorbed through a fluorine-resistant gas distributor. The inlet flow rate was controlled at 0.50 L / min. The hydrolysis reaction temperature was 35℃, the hydrolysis reaction pressure was 0.10 MPa, and the reaction time was 4 h, resulting in an initial enriched... 10 B boric acid hydrolysate. For initially rich 10The boric acid hydrolysate was stirred and matured for another 60 minutes, and the pH of the solution was controlled to 4.2. It was then filtered through a 0.45 μm pore size membrane to obtain a solution rich in boric acid. 10 B boric acid hydrolysate. (The rich...) 10 The boric acid hydrolysate was concentrated under reduced pressure at 70℃ and a vacuum of -0.095 MPa until the boric acid mass concentration in the solution reached 45%, yielding a boric acid-rich solution. 10 B boric acid concentrate. (The rich...) 10 The concentrated boric acid solution was cooled to 12℃ at a cooling rate of 1.5℃ / min and crystallized for 8 hours to obtain a rich boric acid solution. 10 Boric acid crystallizing slurry; for rich boric acid crystals 10 Boric acid crystallization slurry was separated by filtration to obtain wet-state rich boric acid. 10 Boric acid crystals. The wet state rich in boronic acid was treated with high-purity deionized water at 15℃. 10 Boric acid crystals were washed three times and dried at 80°C and a vacuum of -0.098 MPa for 8 hours. They were then passed through a 200-mesh sieve to obtain boric acid powder with abundance calibration.

[0090] S3: Using the abundance-calibrated enriched boric acid powder obtained in S2 as the boron source, and high-purity graphite powder with a purity of 99.999% and a D50 of 3 μm as the carbon source, the abundance-calibrated enriched boric acid powder and high-purity graphite powder are weighed according to a boron to carbon molar ratio of 4:1.05 to obtain the boron-carbon feedstock. The boron-carbon feedstock is added to a mixing container, and anhydrous ethanol is added as the dispersion medium. The amount of anhydrous ethanol added is 120% of the total mass of the boron-carbon feedstock. Premixing is carried out at a stirring speed of 300 r / min for 60 min to obtain a boron-carbon premixed slurry. The boron-carbon premixed slurry is transferred to a zirconia ball mill jar for dispersion and ball milling. The ball-to-powder mass ratio is 8:1, the ball milling speed is 450 r / min, and the ball milling time is 12 h to obtain a boron-carbon dispersion slurry. The boron-carbon dispersion slurry is subjected to preliminary evaporation treatment at 90℃ to reduce the anhydrous ethanol content to 15 wt%, obtaining a wet boron-carbon composite powder. The wet boron-carbon composite powder was placed in a vacuum drying equipment and dried at 120℃ and a vacuum of -0.098MPa for 8 hours to obtain the dried boron-carbon composite powder; then it was ground and passed through a 200-mesh sieve to obtain the boron-carbon composite precursor powder.

[0091] S4: The boron-carbon composite precursor powder obtained in S3 is spread evenly in an alumina crucible with a thickness controlled at 30 mm. The alumina crucible is then placed in an inert atmosphere pre-calcination furnace. High-purity argon gas (99.999%) is introduced into the pre-calcination furnace for purging for 60 min, and the argon flow rate is maintained at 2.0 L / min after purging. The pre-calcination furnace is heated to 450°C at a heating rate of 5°C / min and held for 3 h to obtain low-temperature pre-calcined boron-carbon powder. Then, the temperature is increased to 780°C at a heating rate of 6°C / min and held for 3 h to obtain pre-calcined boron-carbon composite powder. The pre-calcined boron-carbon composite powder is cooled to below 80°C in the furnace and then removed and crushed to a particle size of no more than 2 mm. Subsequently, it is sieved using a 200-mesh sieve, and the undersize material is taken as the pre-reacted boron-carbon composite powder.

[0092] S5: The pre-reacted boron-carbon composite powder obtained in S4 is loaded into a graphite crucible, with a thickness controlled at 50 mm. The graphite crucible is then placed into a vacuum sintering furnace. The vacuum sintering furnace is evacuated to achieve a vacuum level of 5 × 10⁻⁶. -3 The temperature was increased to 900℃ at a rate of 8℃ / min and held for 60 min to obtain vacuum pre-desorbed powder. High-purity argon gas (99.9999%) was introduced into the vacuum sintering furnace, with the furnace pressure controlled at 0.12 MPa and the gas flow rate at 2.0 L / min. The vacuum pre-desorbed powder was heated to 1450℃ at a rate of 10℃ / min under high-purity argon protection and held for 60 min to obtain initially reduced boron-carbon powder. Subsequently, the temperature was further increased to 1920℃ at a rate of 8℃ / min and held for 120 min to complete carbothermic reduction sintering, obtaining rich boron-carbon powder. 10 B. Boron carbide sintering material. (The text abruptly ends here, likely due to an incomplete sentence 10 After the boron carbide sinter was cooled to below 300°C under high-purity argon protection, the gas supply was stopped, and the furnace was cooled to below 80°C. The resulting product was then enriched with high-purity argon. 10 B. Boron carbide sintering intermediate.

[0093] S6: The richness obtained in S5 10 After the boron carbide sintering intermediate is cooled to room temperature, it is coarsely crushed to a particle size of no more than 5 mm to obtain a rich boron carbide intermediate. 10 B. Boron carbide coarse crushed material. For rich... 10 Boron carbide coarse crushed material (B) was ground and crushed using a grinding equipment lined with zirconium oxide. The grinding time was 3 hours, and the crushed material was then passed through a 100-mesh sieve to obtain a rich... 10 B. Boron carbide pre-crushed material. (The text abruptly ends here, likely due to an incomplete sentence or missing information.) 10 Boron carbide pre-crushed material is fed into an air jet mill for air jet milling. The milling medium is high-purity argon gas with a purity of 99.9999%. The milling pressure is 0.9 MPa, the feed rate is 2 kg / h, and the classifier speed is 9000 r / min, resulting in a material rich in argon. 10Boron carbide refined powder. For rich... 10 Boron carbide fine powder was subjected to 1000-mesh sieving, and the undersize powder with D50 of 200 nm and D90 of 500 nm was collected to obtain rich powder. 10 Boron carbide powder (B). A 20g sample was dried at 120℃ and a vacuum of -0.098MPa for 3 hours to obtain the boron-rich powder to be tested. 10 Sample B, boron carbide. Analysis showed that the sample... 10 The measured abundance of B was 96.8%, which is consistent with the target. 10 The abundance deviation of boron was 0.15 percentage points, the free boron content was 0.31 wt%, the free carbon content was 0.21 wt%, the oxygen content was 0.06 wt%, and the total amount of metallic impurities was 65 ppm, indicating a rich boron content. 10 The boron carbide powder has a purity of 99.97%, and this batch of powder is deemed qualified, yielding a rich... 10 Boron carbide products with adjustable boron content.

[0094] Comparative Example 1

[0095] S1: Purchase a commercially available fixed-price product. 10 Boric acid enriched powder with a boron abundance of 85% was used as the boron source, and graphite powder with a purity of 99.5% and a D50 of 5μm was used as the carbon source. The boron and carbon were weighed according to a molar ratio of 4:1.10. Then, the enriched boric acid powder and graphite powder were added to a mixer and dry-mixed at 80r / min for 30min to obtain boron-carbon mixed powder.

[0096] S2: The boron-carbon mixed powder obtained in S1 is loaded into a graphite crucible and placed in a conventional tube furnace. It is then preheated and dehydrated under a nitrogen atmosphere with a nitrogen purity of 99.9% and a nitrogen flow rate of 0.5 L / min. The temperature is increased to 350℃ at a rate of 5℃ / min and held for 1 hour. The temperature is then increased to 750℃ and held for 1 hour to obtain the pretreated boron-carbon powder.

[0097] S3: The pretreated boron-carbon powder obtained in S2 was placed in a high-temperature sintering furnace and subjected to a single carbothermic reduction sintering under nitrogen protection. The nitrogen purity was 99.9%, the furnace pressure was atmospheric pressure, the heating rate was 8℃ / min, the sintering temperature was 1750℃, and the holding time was 60min. After sintering, the powder was cooled to room temperature with the furnace to obtain a fixed... 10 B-abundance boron carbide sintered blocks.

[0098] S4: Fix the result obtained in S3 10 B-abundance boron carbide sintered blocks were coarsely crushed using a jaw crusher to a particle size not exceeding 10 mm; then ground in a conventional ball mill for 2 hours at a speed of 250 r / min, and finally passed through a 300-mesh sieve to obtain conventional fixed-abundance boron carbide sintered blocks. 10 Boron carbide powder with B abundance. Testing revealed that this powder...10 The measured abundance of boron carbide (B) was 84.2%, the boron loss rate was 43%, the product purity was 98.9%, the free boron content was 1.12 wt%, the free carbon content was 0.68 wt%, the oxygen content was 0.32 wt%, and the total metallic impurities were 380 ppm. The flexural strength of the boron carbide sintered sample obtained using this powder was 425 MPa. This comparative example used a fixed-abundance enriched boric acid for direct carbonization and sintering, without boron trifluoride abundance ratio calibration, complexation purification, hydrolysis crystallization, or segmented pre-sintering control.

[0099] Table 1 Comparison of Finished Product Performance Parameters

[0100]

[0101] As can be seen from Table 1, after using the combined process of boron trifluoride gas source abundance ratio calibration, complexation purification, hydrolysis crystallization, segmented pre-calcination, and vacuum inert atmosphere carbothermic reduction sintering in Example 1, the finished product... 10 The abundance of boric acid (B) remained consistent with the target abundance, with an abundance deviation of 0.00 percentage points, significantly better than Examples 2, 3, and Comparative Example 1. Comparative Example 1 used commercially available boric acid enriched at a fixed 85% abundance for direct carbothermal reduction, and the finished product... 10 The measured abundance of B was only 84.2%, with a deviation of 0.80 percentage points, indicating that it could not be precisely adjusted according to the target abundance, and that boron loss was significant during sintering. Meanwhile, Example 1 showed a boron loss rate of only 12.6%, a product purity of 99.96%, a free boron content of 0.18 wt%, a free carbon content of 0.12 wt%, an oxygen content of 0.04 wt%, and a total metal impurity content of 38 ppm. All impurity indicators were lower than those of other examples and Comparative Example 1. The sintered sample obtained using the powder from Example 1 achieved a flexural strength of 535 MPa, higher than the 486 MPa of Example 2, the 512 MPa of Example 3, and the 425 MPa of Comparative Example 1, indicating that Example 1 performed best in terms of abundance control, impurity control, and finished product mechanical properties.

[0102] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0103] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A kind of rich 10 A method for preparing boron carbide with adjustable boron content, characterized in that, Includes the following steps: S1: Based on the target of the boron carbide product to be prepared 10 B abundance, select at least two. 10 Boron trifluoride gas sources with different abundances were mixed in a specific ratio, and the mixed boron trifluoride gas was purified to obtain boron trifluoride gas enriched with abundance calibration. S2: The abundance-calibrated boron trifluoride gas obtained in S1 is introduced into high-purity deionized water for hydrolysis to obtain a rich... 10 B boric acid hydrolysate; and for rich boric acid hydrolysate; 10 The boric acid hydrolysate was subjected to crystallization, solid-liquid separation and drying to obtain boric acid powder with abundance calibration. S3: The boric acid powder obtained from S2 with abundance calibration enrichment was used as a boron source and mixed with high-purity graphite powder, dispersed, ball-milled and dried to obtain boron-carbon composite precursor powder. S4: The boron-carbon composite precursor powder obtained in S3 is placed in an inert atmosphere for segmented pre-calcination to obtain pre-calcined boron-carbon composite powder; and the pre-calcined boron-carbon composite powder is crushed and sieved to obtain pre-reacted boron-carbon composite powder. S5: The pre-reacted boron-carbon composite powder obtained in S4 is placed in a vacuum sintering environment and subjected to carbothermic reduction sintering under high-purity inert gas protection to obtain a rich... 10 Boron carbide sintering intermediate; S6: The richness obtained from S5 10 The boron carbide sintering intermediate was crushed, air jet milled, and graded and sieved to obtain a rich boron carbide sintering intermediate. 10 Boron carbide powder; and for rich boron carbide powder; 10 Boron carbide powder is subjected to 10 B abundance and impurity content were detected, and after passing the tests, the product was considered rich. 10 Boron carbide products with adjustable boron content.

2. A rich [material] according to claim 1 10 A method for preparing boron carbide with adjustable boron content, characterized in that, S1 specifically includes: S11: Determine the target for the boron carbide product to be prepared. 10 B abundance The target 10 B abundance The content is 70%–97%, and at least two types are selected from the boron trifluoride gas source group. 10 Boron trifluoride gas sources with different abundances are used as the gas sources to be mixed. The boron trifluoride gas source group includes... 10 A first boron trifluoride gas source with a boron abundance of 70%–80%, 10 A boron trifluoride gas source with a boron abundance of 80%–90% and 10 A third boron trifluoride gas source with a boron abundance of 90%–97%; S12: Obtain the gas sources to be mixed respectively. 10 B Measured Abundance And according to the target 10 B abundance and each gas source to be mixed 10 B Measured Abundance Determine the intake flow rate of each gas source to be mixed. The intake flow rates of each gas source to be mixed satisfy: ,in, The quantity of gas sources to be mixed, and The single-path intake flow rate of each gas source to be mixed The flow rate is 0.05–5 L / min, and the total mixed flow rate is 0.2–10 L / min; S13: Each gas source to be mixed is introduced into the corresponding drying and filtration branch for pretreatment. The drying and filtration branch includes a molecular sieve drying column and a microporous filter. The drying temperature is 20-35℃, and the dew point of the gas after drying is not higher than -40℃. The filtration accuracy of the microporous filter is 0.01-0.1μm, and the corresponding pretreated boron trifluoride gas is obtained. S14: The pretreated boron trifluoride gases obtained in S13 are respectively fed into the gas mixing tank via a mass flow controller, according to the inlet flow rate determined in S12. Continuous gas mixing is performed, with the pressure inside the gas mixing tank controlled at 0.02–0.15 MPa, the mixing temperature controlled at 15–35 °C, and the mixing time at 20–60 min, to obtain the mixed boron trifluoride gas.

3. A rich [material] according to claim 2 10 A method for preparing boron carbide with adjustable boron content, characterized in that, S1 further includes: S15: The mixed boron trifluoride gas obtained in S14 is introduced into a complexation absorption tank to react with the ethylene glycol dimethyl ether complexing agent. The molar ratio of the ethylene glycol dimethyl ether complexing agent to the boron trifluoride in the mixed boron trifluoride gas is 1.05:1 to 1.30:

1. The complexation absorption temperature is 15 to 30°C, the complexation absorption pressure is 0.03 to 0.20 MPa, and the complexation absorption time is 1 to 4 h to obtain a boron trifluoride complex solution. S16: The boron trifluoride complex obtained in S15 is transferred to the decomposition and purification unit for decomposition at a temperature of 75–95°C, a pressure of 0.01–0.08 MPa, and a time of 0.5–3 h, releasing decomposition boron trifluoride gas. The decomposition boron trifluoride gas is then passed sequentially through a cold trap and a filter. The cold trap temperature is -50–-20°C, and the filter accuracy is 0.01–0.05 μm, to obtain purified boron trifluoride gas. S17: The purified boron trifluoride gas obtained in S16 is subjected to... 10 B abundance and purity detection, when purifying boron trifluoride gas 10 B Measured abundance and target 10 B abundance When the deviation is no greater than 0.3 percentage points and the purity of boron trifluoride is no less than 99.5%, the purified boron trifluoride gas is used as the abundance calibration enrichment gas for boron trifluoride.

4. A rich [product / method] according to claim 1 10 A method for preparing boron carbide with adjustable boron content, characterized in that, S2 specifically includes: S21: Add high-purity deionized water with a resistivity of not less than 18 MΩ·cm to the hydrolysis reactor, control the initial temperature of the high-purity deionized water to be 5-25℃, and form the water phase to be absorbed under stirring conditions of 80-250 r / min; S22: The abundance-calibrated boron trifluoride gas obtained in S1 is introduced into the aqueous phase to be absorbed obtained in S21 through a fluorine-resistant gas distributor. The inlet flow rate is controlled at 0.03–0.50 L / min, the hydrolysis reaction temperature is 10–35℃, the hydrolysis reaction pressure is 0.01–0.10 MPa, and the reaction time is 0.5–4 h to obtain the initial enriched... 10 B boric acid hydrolysate; S23: The initial richness obtained from S22 10 The boric acid hydrolysate was stirred and matured for another 20–60 minutes, with the pH adjusted to 2.8–4.

2. It was then filtered through a membrane with a pore size of 0.1–0.45 μm to obtain a solution rich in boric acid. 10 B boric acid hydrolysate; S24: The richness obtained from S23 10 The boric acid hydrolysate was concentrated under reduced pressure at a temperature of 45–70 °C and a vacuum degree of -0.06–-0.095 MPa until the boric acid mass concentration in the solution reached 20%–45%, yielding a boric acid-rich solution. 10 B. Boric acid concentrate.

5. A rich [product / method] according to claim 4 10 A method for preparing boron carbide with adjustable boron content, characterized in that, S2 further includes: S25: The richness obtained from S24 10 The concentrated boric acid solution was cooled to 2–12°C for crystallization at a cooling rate of 0.2–1.5°C / min for 2–8 hours to obtain a rich boric acid solution. 10 Boric acid crystallizing slurry; for rich boric acid crystals 10 The boric acid crystal slurry was filtered to obtain a wet-state rich boric acid crystal. 10 B-boronic acid crystals; S26: The wet enrichment obtained from S25 is processed with high-purity deionized water at 5-15℃. 10 Boric acid crystals were washed 1–3 times and dried at 50–80°C and a vacuum of -0.08–-0.098 MPa for 2–8 hours. They were then passed through an 80–200 mesh sieve to obtain boric acid powder with enrichment calibrated by abundance.

6. A rich [material] according to claim 1 10 A method for preparing boron carbide with adjustable boron content, characterized in that, S3 specifically includes: S31: Take the abundance-calibrated boric acid powder obtained in S2 as the boron source, and take high-purity graphite powder with a purity of not less than 99.99% and a D50 of 0.5 to 3 μm as the carbon source; weigh the abundance-calibrated boric acid powder and high-purity graphite powder according to the molar ratio of boron to carbon of 4:0.98 to 1.05 to obtain the boron-carbon feedstock composition. S32: Add the boron-carbon ingredient components obtained in S31 into a mixing container, and add anhydrous ethanol as a dispersion medium. The amount of anhydrous ethanol added is 40% to 120% of the total mass of the boron-carbon ingredient components. Premix at a stirring speed of 100 to 300 r / min for 20 to 60 min to obtain boron-carbon premixed slurry. S33: The boron-carbon premixed slurry obtained in S32 is transferred into a ball mill jar for dispersion ball milling. Both the ball mill jar and the grinding balls are made of zirconium oxide. The ball-to-material mass ratio is 3-8:1, the ball milling speed is 200-450 r / min, and the ball milling time is 4-12 h to obtain the boron-carbon dispersion slurry. S34: The boron-carbon dispersion slurry is subjected to solid-liquid transfer and preliminary evaporation treatment at 60-90℃ to reduce the anhydrous ethanol content in the boron-carbon dispersion slurry to 5wt%-15wt%, thereby obtaining wet boron-carbon composite powder. S35: Place the wet boron-carbon composite powder in a vacuum drying equipment and dry it for 3 to 8 hours at 80 to 120°C and a vacuum degree of -0.08 to -0.098 MPa to obtain dry boron-carbon composite powder; then grind the dry boron-carbon composite powder and pass it through an 80 to 200 mesh sieve to obtain boron-carbon composite precursor powder.

7. A rich [material] according to claim 1 10 A method for preparing boron carbide with adjustable boron content, characterized in that, S4 specifically includes: S41: Spread the boron-carbon composite precursor powder obtained in S3 in an alumina crucible, with the thickness of the spread material controlled at 5-30 mm, and place the alumina crucible containing the boron-carbon composite precursor powder into an inert atmosphere pre-calcination furnace. S42: High-purity argon or high-purity nitrogen is introduced into the inert atmosphere pre-burning furnace for replacement. The purity of the inert gas is not less than 99.99%, and the replacement time is 20 to 60 minutes. After replacement, the inert gas flow rate is maintained at 0.2 to 2.0 L / min. S43: The inert atmosphere pre-calcination furnace is heated to 300-450℃ at a heating rate of 2-5℃ / min and held for 1.5-3h to obtain low-temperature pre-calcined boron-carbon powder. S44: The low-temperature pre-calcined boron-carbon powder is further heated to 650-780℃ at a heating rate of 2-6℃ / min and held for 1.5-3h to obtain pre-calcined boron-carbon composite powder; S45: After the pre-burned boron-carbon composite powder obtained in S44 is cooled to below 80°C in the furnace, it is taken out and crushed. The particle size of the crushed powder is controlled to be no more than 2mm. S46: The pre-burned boron-carbon composite powder after crushing S45 is sieved and collected sequentially. The sieve mesh size is 80-200 mesh, and the material passing through the sieve is taken as the pre-reacted boron-carbon composite powder.

8. A rich [material] according to claim 1 10 A method for preparing boron carbide with adjustable boron content, characterized in that, S5 specifically includes: S51: Load the pre-reacted boron-carbon composite powder into a graphite crucible, control the thickness of the material to be 10-50mm, and place the graphite crucible containing the pre-reacted boron-carbon composite powder into a vacuum sintering furnace. S52: Vacuum the vacuum sintering furnace to achieve a vacuum level of 1×10⁻⁶. -2 ~5×10 -3 Pa, and heated to 600-900℃ at a heating rate of 3-8℃ / min, and held for 20-60min to obtain vacuum pre-desorbed powder; S53: High-purity argon or high-purity nitrogen is introduced into the vacuum sintering furnace. The purity of the high-purity argon or high-purity nitrogen is not less than 99.999%. The gas pressure inside the furnace is controlled at 0.02 to 0.12 MPa, and the gas flow rate is controlled at 0.2 to 2.0 L / min. S54: The vacuum pre-desorbed powder obtained in S52 is heated to 1200-1450℃ under the protection of high-purity inert gas in S53, with a heating rate of 5-10℃ / min, and held for 20-60min to obtain the preliminary reduced boron carbon powder. S55: The preliminarily reduced boron-carbon powder obtained in S54 is further heated to 1750–1920℃ at a heating rate of 3–8℃ / min and held at that temperature for 30–120 min to complete the carbothermic reduction sintering and obtain a rich boron-carbon powder. 10 B. Boron carbide sintering material; S56: The richness obtained from S55 10 After the boron carbide sintering material was cooled to below 300°C under high-purity inert gas protection, the gas supply was stopped, and it was cooled to below 80°C with the furnace. The resulting product was rich in boron carbide. 10 B. Boron carbide sintering intermediate.

9. A rich [material] according to claim 1 10 A method for preparing boron carbide with adjustable boron content, characterized in that, S6 specifically includes: S61: The richness obtained from S5 10 After the boron carbide sintering intermediate is cooled to room temperature, it is coarsely crushed to a particle size of no more than 5 mm to obtain a rich boron carbide intermediate. 10 B. Boron carbide coarse crushed material; S62: The richness obtained from S61 10 Boron carbide coarse crushed material (B) is ground and crushed. The grinding equipment is lined with boron carbide, silicon nitride, or zirconium oxide. The grinding time is 0.5–3 hours. After grinding, the material is passed through a 40–100 mesh sieve to obtain a rich... 10 B. Boron carbide pre-crushed material; S63: The richness obtained from S62 10 Boron carbide pre-crushed material is fed into an air jet mill for air jet milling. The milling medium is high-purity nitrogen or high-purity argon gas with a purity of not less than 99.999%. The milling pressure is 0.4–0.9 MPa, the feed rate is 0.2–2 kg / h, and the classifier speed is 3000–9000 r / min, to obtain a material rich in boron carbide. 10 Boron carbide refined powder; S64: The richness obtained from S63 10 Boron carbide fine powder was graded and sieved at a mesh size of 300–1000 mesh. The undersize powder with a D50 of 50–200 nm and a D90 not exceeding 500 nm was collected to obtain a rich powder. 10 B. Boron carbide powder.

10. A rich [material] according to claim 9 10 A method for preparing boron carbide with adjustable boron content, characterized in that, S6 specifically includes: S65: From wealth 10 A sample of 5–20 g of boron carbide powder was taken and dried at 80–120 °C and a vacuum of -0.08–-0.098 MPa for 1–3 h to obtain the boron-rich sample to be tested. 10 B boron carbide sample; S66: Treatment of rich substances in the test 10 Boron carbide sample B was subjected to 10 B abundance detection, free boron content detection, free carbon content detection, oxygen content detection, and metal impurity content detection; S67: When detected by S66 10 B Measured abundance and target 10 The abundance deviation of boron is no greater than 0.3 percentage points, the free boron content is no greater than 0.5 wt%, the free carbon content is no greater than 0.3 wt%, the oxygen content is no greater than 0.1 wt%, the total amount of metallic impurities is no greater than 100 ppm, and it is rich in... 10 When the purity of boron carbide powder is not less than 99.9%, the corresponding batch of rich... 10 Boron carbide powder as a rich 10 Boron carbide products with adjustable boron content.

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