Systems and methods for making boric acid

Abstract

The embodiment of the invention relates to the technical field of preparation of boron compounds, in particular to a system and a method for preparing boric acid. The system comprises a complexing device, an esterification device, a front-stage separation device, a hydrolysis crystallization device, a rear-stage separation device and a drying device, the complexing device is used for carrying out complexing reaction on boron trifluoride and methanol to generate a complex; the esterification device is used for carrying out esterification reaction on the complex and a solid defluorinating agent to generate trimethyl borate and a solid by-product; the preceding-stage separation device is used for separating trimethyl borate from solid byproducts; the hydrolysis crystallization device is used for carrying out hydrolysis reaction on trimethyl borate and a hydrolytic agent to generate boric acid and methanol, and crystallizing the boric acid; the post-stage separation device is used for separating crystallized boric acid from liquid components; the drying device is used for drying the separated boric acid. According to the system for preparing the boric acid, the devices are connected in series, so that the loss of materials can be reduced, the conversion rate of the materials is improved, and the preparation of nuclear grade boric acid-10 is facilitated.

Description

Technical Field

[0001] The embodiments of this application relate to the technical field of preparing boron compounds, and particularly to a system and method for producing boric acid. Background Technology

[0002] This section is only intended to provide background information relevant to this application and does not necessarily constitute prior art.

[0003] Boron has two stable isotopes: boron-10 and boron-11. Replacing natural boronic acid with boron-10-enriched boric acid in reactor water chemistry control can reduce the overall amount of boric acid used in the reactor cooling system, decrease the alkalinity of the primary coolant, reduce corrosiveness, and extend reactor life while maintaining the same boron-10 concentration. Currently, research on replacing natural boronic acid with boron-10-enriched boric acid in reactor water chemistry control is underway.

[0004] However, there are still many limitations in the preparation of nuclear-grade boric acid. Summary of the Invention

[0005] A brief overview of this application is provided below to offer a basic understanding of certain aspects thereof. It should be understood that this overview is not an exhaustive summary of the application. It is not intended to identify key or essential parts of the application, nor is it intended to limit its scope. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0006] In a first aspect, embodiments of this application provide a system for manufacturing boric acid. The system includes: a complexing device, an esterification device, a pre-separation device, a hydrolysis crystallization device, a post-separation device, and a drying device; the complexing device is used to allow boron trifluoride to undergo a complexation reaction with methanol to generate a complex; the esterification device is used to allow the complex to undergo an esterification reaction with a solid defluorinating agent to generate trimethyl borate and a solid byproduct; the pre-separation device is used to separate the trimethyl borate from the solid byproduct; the hydrolysis crystallization device is used to allow the trimethyl borate and a hydrolyzing agent to undergo a hydrolysis reaction to generate boric acid and methanol, and to crystallize the boric acid; the post-separation device is used to separate the crystallized boric acid from the liquid components; and the drying device is used to dry the boric acid separated by the post-separation device.

[0007] In the embodiments of this application, since the complexation reaction, esterification reaction, and hydrolysis reaction of the materials are carried out in different devices, it is beneficial to control each reaction process individually, thereby making each reaction more thorough and resulting in higher purity of the prepared nuclear-grade boric acid, which is beneficial for the preparation of nuclear-grade boric acid-10. Furthermore, by connecting the devices in series, the product of the previous device can be directly used as the raw material for the next device, reducing material loss and thus improving the material conversion rate.

[0008] Secondly, embodiments of this application provide a method for manufacturing boric acid. The method is implemented using the system for manufacturing boric acid provided in the first aspect of this application. The method includes: S1, mixing boron trifluoride with methanol to undergo a complexation reaction to generate a complex; S2, mixing the complex with a solid defluorinating agent to undergo an esterification reaction to generate trimethyl borate and a solid byproduct; S3, separating the trimethyl borate from the solid byproduct; S4, mixing the trimethyl borate with a hydrolyzing agent to undergo a hydrolysis reaction to generate boric acid and methanol, and crystallizing the boric acid; S5, separating the crystallized boric acid from the liquid components; and S6, drying the separated boric acid.

[0009] These and other advantages of this application will become more apparent from the following detailed description of preferred embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0010] To further illustrate the above and other advantages and features of this application, the specific embodiments of this application will be described in more detail below with reference to the accompanying drawings. The drawings, together with the following detailed description, are included in and form a part of this specification. Elements having the same function and structure are indicated by the same reference numerals. It should be understood that these drawings only depict typical examples of this application and should not be considered as limiting the scope of this application.

[0011] Figure 1 This is a schematic diagram of a system for manufacturing boric acid according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a complexing device according to an embodiment of this application; Figure 3 This is a cross-sectional view of a complexing device according to an embodiment of this application; Figure 4 This is a schematic diagram of a spray component according to an embodiment of this application; Figure 5 This is a schematic diagram of the structure of an esterification apparatus according to an embodiment of this application; Figure 6 This is a cross-sectional view of an esterification apparatus according to an embodiment of this application; Figure 7 This is a schematic diagram of the structure of a hydrolysis crystallization apparatus according to an embodiment of this application; Figure 8 This is a cross-sectional view of a hydrolysis crystallization apparatus according to an embodiment of this application; Figure 9 This is a schematic diagram of the structure of a crystal collecting assembly according to an embodiment of this application; Figure 10 This is a cross-sectional view of a crystal collecting assembly according to an embodiment of this application; Figure 11This is a schematic diagram of the structure of the conical cylindrical component of the separator according to an embodiment of this application; Figure 12 This shows the flow path of materials in the hydrolysis crystallization apparatus.

[0012] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding.

[0013] Explanation of reference numerals in the attached figures: 1. Complexing device; 10. Complexing container; 100. Complexing chamber; 11. Packing material; 12. Intake assembly; 120. Intake piping; 121. Intake valve; 122. Pressure regulator; 13. Liquid inlet / outlet assembly; 130. Liquid inlet pipeline; 1300. Liquid inlet valve; 1301. Liquid inlet / outlet valve; 131. Liquid outlet pipeline; 1310. Liquid outlet valve; 132. Spray pipeline; 1320. Spray valve; 133. Circulation pump; 134. Spray component; 1341. Conical surface; 1342. Curved surface; 1343. Water outlet; 135. Liquid inlet / outlet pipeline; 136. Connecting pipeline; 14. Measuring component; 140. Temperature measuring element; 141. Liquid level measuring element; 1410. Liquid level measuring chamber; 142. Pressure measuring element; 15. Observation window; 16. Drain port; 17. Vacuuming pipeline; 18. Vacuuming valve; 19. Drain valve; 2. Esterification device; 20. Esterification container; 200. Esterification chamber; 201. Liquid inlet; 202. Feed inlet; 203. Discharge outlet; 204. Vacuum port; 205. Exhaust valve; 206. Exhaust port; 21. Heating element; 210. Heating chamber; 211. Heating medium inlet; 212. Heating medium outlet; 213. Baffle plate; 22. Stirring assembly; 220. Stirring component; 2201. Drive motor; 2202. Stirring shaft; 2203. Blades; 221. Stirring auxiliary components; 23. Temperature measuring element; 24. Pressure measuring element; 25. Safety valve; 26. Conductivity measuring element; 27. Observation window; 3. Hydrolysis crystallization apparatus; 30. Container body; 300. Hydrolysis crystallization chamber; 301. Feed inlet; 302. First cylindrical component; 303. First conical component; 304. Baffle; 3040. Inclined surface; 305. Safety valve; 306. Vacuum port; 307. Discharge valve; 308. Hydrolyzing agent inlet; 31. Circulating heating assembly; 310. Circulating piping; 311. Circulating pump; 312. Heat exchanger; 32. Flow guide; 320. Second cylindrical component; 321. Second conical component; 3210. Heated material inlet; 3211. Heated material outlet; 3212. Flow guide chamber; 33. Stirring assembly; 330. Drive motor; 331. Stirring shaft; 332. Blades; 34. Crystal collecting assembly; 340. Collecting body; 3401. Collecting cavity; 3402. Return through hole; 3403. Cylindrical component; 3404. Base plate; 34040. Channel; 3405. Top plate; 3406. Connecting through hole; 341. Separator; 3410. Separation cavity; 3411. Upper through hole; 3412. Conical cylindrical part; 3413. Divider; 3414. Bowl-shaped part; 34141. Cylindrical section; 34142. Smooth transition section; 3415. Bottom through hole; 35. Steam collection component; 350. Steam outlet pipe; 351. Condensation component; 352. Receiving container; 36. Sight glass; 37. Conductivity measuring device; 38. Temperature measuring device; 39. Pressure measuring device;

[0014] 4. Pre-separation unit; 5. Post-separation unit; 6. Drying unit. Detailed Implementation

[0015] Exemplary embodiments of this application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of actual implementations are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the development of any such actual embodiment to achieve the developer's specific goals, such as complying with constraints related to the system and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the content of this application.

[0016] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the equipment structure and / or processing steps closely related to the solution according to this application are shown in the accompanying drawings, while other details that are not closely related to this application are omitted.

[0017] It should be noted that, unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning as understood by a person with ordinary skills in the field to which this application pertains.

[0018] In the description of the embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0019] Methods for producing boric acid from boron trifluoride include direct hydrolysis, alkali metal hydroxide method, borate method, alcoholysis-hydrolysis method, and fluoroboronic acid indirect method. The HF generated by direct hydrolysis is highly corrosive and difficult to treat; the alkali metal hydroxide method requires large amounts of acid and alkali, resulting in high costs; the purity of boric acid obtained by the borate method depends heavily on the purity of borax, leading to high uncertainty; the fluoroboronic acid indirect method involves complex equipment and significant investment; the alcoholysis-hydrolysis method can reduce HF generation, and the alcohols used can be recycled.

[0020] However, when preparing boric acid using the alcoholysis-hydrolysis method, the relevant techniques usually involve directly introducing boron trifluoride gas into the reaction system containing methanol, causing it to form a complex on-site and immediately participate in subsequent reactions. This method is only suitable for small-scale laboratory preparation and has problems such as uneven reaction and easy generation of local high temperatures. The purity of the prepared boron trifluoride-methanol complex is also not high, which affects the purity of the subsequent preparation of nuclear-grade boric acid.

[0021] Based on this, embodiments of this application provide a system for manufacturing boric acid to improve the purity of the produced boric acid, thereby facilitating the acquisition of nuclear-grade boric acid.

[0022] See Figure 1 , Figure 1 This is a schematic diagram of a system for manufacturing boric acid according to an embodiment of this application. The system for manufacturing boric acid according to this embodiment may include: a complexing device 1, an esterification device 2, a pre-separation device 4, a hydrolysis crystallization device 3, a post-separation device 5, and a drying device 6; the complexing device 1 is used to allow boron trifluoride to undergo a complexation reaction with methanol to generate a complex; the esterification device 2 is used to allow the complex to undergo an esterification reaction with a solid defluorinating agent to generate trimethyl borate and solid byproducts; the pre-separation device 4 is used to separate trimethyl borate from the solid byproducts; the hydrolysis crystallization device 3 is used to allow trimethyl borate to undergo a hydrolysis reaction with a hydrolyzing agent to generate boric acid and methanol, and to crystallize the boric acid; the post-separation device 5 is used to separate the crystallized boric acid from the liquid components; and the drying device 6 is used to dry the boric acid separated by the post-separation device 5.

[0023] In the embodiments of this application, since the complexation reaction, esterification reaction, and hydrolysis reaction of the materials are carried out in different devices, it is beneficial to control each reaction process individually, thereby making each reaction more thorough and resulting in higher purity of the prepared nuclear-grade boric acid, which is beneficial for the preparation of nuclear-grade boric acid-10. Furthermore, by connecting the devices in series, the product of the previous device can be directly used as the raw material for the next device, reducing material loss and improving material conversion rate. The raw materials for the complexation reaction are boron trifluoride and methanol, while the product of the hydrolysis crystallization reaction is methanol, which facilitates the recycling of raw materials.

[0024] In some embodiments, see Figure 2and Figure 3 , Figure 2 This is a schematic diagram of the complexing device 1 according to an embodiment of this application. Figure 3 This is a cross-sectional view of a complexing device 1 according to an embodiment of this application. The complexing device 1 may include: a complexing container 10, a packing 11, an air inlet assembly 12, a liquid inlet / outlet assembly 13, and a measuring assembly 14; the complexing container 10 forms a complexing chamber 100; the packing 11 is disposed within the complexing chamber 100; the air inlet assembly 12 is configured to supply boron trifluoride gas to the complexing chamber 100; the liquid inlet / outlet assembly 13 is configured to supply methanol liquid to the complexing chamber 100, and to circulate and spray the methanol liquid at the top of the complexing chamber 100 so that the methanol liquid reacts with the boron trifluoride gas within the complexing chamber 100 to form a complex, and to discharge the complex from the complexing chamber 100; the measuring assembly 14 is configured to measure the physical parameters of the complexing chamber 100; wherein, the complexing container 10 is configured to dissipate heat from within the complexing chamber 100 to the external environment using the surface of the complexing container 10.

[0025] In this embodiment, by introducing boron trifluoride gas into the complexing chamber 100 and circulating and spraying methanol liquid at the top of the complexing chamber 100, the contact area between the methanol liquid and the boron trifluoride gas can be increased. By providing packing material 11 in the complexing chamber 100, the sprayed methanol can achieve higher mass transfer and reaction efficiency through the packing material 11, enhancing the reaction contact between the gas and liquid phases, promoting thorough mixing of the methanol liquid and the boron trifluoride gas, thereby promoting their reaction. Furthermore, by providing packing material 11, the reaction heat in the complexing chamber 100 can be dispersed to avoid heat accumulation leading to localized heat concentration. Moreover, by utilizing the surface of the complexing container 10 to dissipate the heat inside the complexing chamber 100 to the external environment, forced heat dissipation of the complexing chamber 100 is unnecessary. This also achieves a uniform and mild reaction between the methanol liquid and the boron trifluoride gas, obtaining a high-purity boron trifluoride-methanol complex, which can then be used to prepare nuclear-grade boric acid.

[0026] In some embodiments, the height of the complexing container 10 can be more than seven times its diameter. By setting the height of the complexing container 10 to more than seven times its diameter, the complexing container 10 can be made more slender, which is more conducive to heat dissipation of the complexing chamber 100 by the surface of the complexing container 10. This is more conducive to achieving a uniform and mild reaction between methanol liquid and boron trifluoride gas without the need for forced heat dissipation of the complexing chamber 100, thereby obtaining a high-purity boron trifluoride-methanol complex.

[0027] The complexing container 10 may include an elongated cylindrical body and two end caps that seal the body at the top and bottom, respectively. The end caps and the body may be connected by bolts.

[0028] In some embodiments, such as Figure 3 As shown, the packing 11 can be formed by stacking multiple layers of packing units along the height direction of the complexing chamber 100. In this embodiment, by stacking multiple layers of packing units along the height direction of the complexing chamber 100, the total surface area of ​​the packing 11 can be increased, which also facilitates repeated contact between methanol liquid and boron trifluoride gas, thereby making the reaction between the two more complete. By setting multiple layers of packing units, the reaction heat of the complexing chamber 100 can be effectively dispersed, thereby avoiding local overheating.

[0029] In some embodiments, the packing unit can be a structured packing, which has good separation efficiency, large flow rate, low pressure drop, good corrosion resistance and high temperature resistance, compact structure, and is easy to maintain.

[0030] In some embodiments, the liquid level in the complexing chamber 100 may be below the packing 11; the gas inlet assembly 12 is configured to introduce boron trifluoride gas below the packing 11 and above the liquid level. In this embodiment, by introducing boron trifluoride gas below the packing 11 and above the liquid level, a countercurrent gas-liquid exchange motion can be achieved, allowing for more thorough contact between the methanol liquid and the boron trifluoride gas, thereby improving the reaction efficiency.

[0031] In some embodiments, such as Figure 2 As shown, the intake assembly 12 may include: an intake pipe 120 and a pressure regulator 122; the intake pipe 120 is configured to introduce boron trifluoride gas into the complexing chamber 100; the pressure regulator 122 is configured to regulate the pressure of the boron trifluoride gas.

[0032] In this embodiment, boron trifluoride gas enters the complexation chamber 100 through the inlet pipe 120 and undergoes a complexation reaction with methanol liquid. The pressure of the boron trifluoride gas is adjusted by the pressure regulator 122 to ensure that the gas pressure entering the complexation chamber 100 does not exceed a specific pressure range.

[0033] In some embodiments, the pressure regulator 122 may be a pressure reducing valve to reduce the pressure of boron trifluoride gas entering the complexing chamber 100.

[0034] In some embodiments, such as Figure 2 As shown, the complexing container 10 may also include a vacuum line 17 and a vacuum valve 18. The vacuum line 17 is used to evacuate the complexing chamber 100 to prevent residual moisture in the complexing chamber 100 from reacting with the gaseous medium to generate acidic substances, causing corrosion damage to the equipment.

[0035] In some embodiments, such as Figure 2As shown, an intake valve 121 is provided on the intake pipe 120. After the complexing chamber 100 is evacuated, the vacuum valve 18 is closed and the intake valve 121 is opened, so that boron trifluoride gas enters the complexing chamber 100 through the intake pipe 120.

[0036] In some embodiments, such as Figure 2 and Figure 3 As shown, the liquid inlet / outlet assembly 13 includes an inlet pipe 130, a circulation pipe, an outlet pipe 131, a circulation pump 133, and a spray element 134. The inlet pipe 130 is used to deliver methanol liquid to the complexing chamber 100. The spray element 134 is disposed at the top of the complexing chamber 100 and is located above the packing 11. The circulation pipe is used to connect the bottom of the complexing chamber 100 and the spray element 134. The outlet pipe 131 is used to discharge the complex from the complexing chamber 100. The circulation pump 133 is configured to deliver the liquid at the bottom of the complexing chamber 100 to the spray pipe 132 for spraying downward by the spray element 134, or to deliver the liquid at the bottom of the complexing chamber 100 to the outlet pipe 131.

[0037] In this embodiment, methanol liquid enters the circulation pump 133 through the inlet pipe 130. The circulation pump 133 transports the methanol liquid to the top of the complexing chamber 100 through the circulation pipe, and sprays the methanol liquid from the top of the complexing chamber 100 downwards through the spray element 134, allowing the methanol liquid to pass through the packing 11 from top to bottom. Compared with allowing the liquid to flow directly through the packing 11 from top to bottom, this allows the methanol liquid to cover the complexing chamber 100 more evenly, increasing the contact area between the methanol liquid and the packing 11, thereby improving the mass transfer and reaction efficiency of the methanol liquid. After the complexation reaction is completed, the generated complex enters the circulation pump 133, and the circulation pump 133 transports the generated complex to the outlet pipe 131.

[0038] In some embodiments, such as Figure 4 As shown, Figure 4 This is a schematic diagram of a spray member according to an embodiment of the present application. The spray member 134 can form a spray chamber and a plurality of water outlet holes 1343 communicating with the spray chamber. After the liquid enters the spray chamber, it is sprayed outward from the water outlet holes 1343.

[0039] In some embodiments, the spray element 134 may include a conical surface 1341 and a curved surface 1342, with the curved surface 1342 connected to the end of the conical surface 1341 with a larger inner diameter, and a water outlet 1343 formed on the curved surface 1342. This structure is more conducive to the uniform distribution of methanol liquid sprayed by the spray element 134 within the complexing chamber 100, avoiding local accumulation of methanol liquid.

[0040] In some embodiments, such as Figure 2As shown, the circulation pipeline may include a spray pipeline 132, an inlet / outlet pipeline 135, and a connecting pipeline 136. The spray pipeline 132 connects the inlet of the spray element 134 to the outlet of the circulation pump 133; the inlet / outlet pipeline 135 connects to the outlet at the bottom of the complexing chamber 100; and the connecting pipeline 136 connects to the inlet of the circulation pump 133. The inlet pipeline 130, inlet / outlet pipeline 135, and connecting pipeline 136 are connected via a tee. The outlet pipeline 131 is connected to the spray pipeline 132.

[0041] The inlet / outlet assembly 13 also includes an inlet valve 1300, an inlet / outlet valve 1301, an outlet valve 1310, and a spray valve 1320. The inlet valve 1300 is located on the inlet pipe 130 and is used to control the opening and closing of the inlet pipe 130. The inlet / outlet valve 1301 is located on the inlet / outlet pipe 135 and is used to control the opening and closing of the inlet / outlet pipe 135. The outlet valve 1310 is located on the outlet pipe 131 and is used to control the opening and closing of the outlet pipe 131. The spray valve 1320 is located on the spray pipe 132 and is used to control the opening and closing of the spray pipe 132.

[0042] When methanol liquid is added to the complexing chamber 100, the inlet valve 1300 and the inlet / outlet valve 1301 are opened, and the methanol liquid enters the bottom of the complexing chamber 100 through the inlet pipe 130 and the inlet / outlet pipe 135. Then, the inlet valve 1300 is closed, the inlet / outlet pipe 135 and the spray valve 1320 are opened, and the circulation pump 133 is started. The methanol liquid enters the inlet of the circulation pump 133 through the inlet / outlet pipe 135 and the connecting pipe 136, and enters the spray pipe 132 and the spray element 134 from the outlet of the circulation pump 133 for spraying. After the reaction is complete, when discharging, the inlet / outlet valve 1301 and the outlet valve 1310 are opened, and the inlet valve 1300 and the spray valve 1320 are closed, allowing the complex generated by the reaction to enter the circulation pump 133, and under the action of the circulation pump 133, the complex is transported to the outlet pipe 131.

[0043] In some embodiments, such as Figure 3 As shown, the measuring component 14 may include a temperature measuring element 140, a liquid level measuring element 141, and a pressure measuring element 142; the temperature measuring element 140 is used to measure the temperature of the complexing chamber 100; the liquid level measuring element 141 is used to measure the liquid level of the complexing chamber 100; and the pressure measuring element 142 is configured to measure the pressure of the complexing chamber 100.

[0044] In this embodiment, the temperature of the complexation chamber 100 during the complexation process of methanol liquid and boron trifluoride gas is measured by the temperature measuring device 140. When the measured temperature exceeds a certain temperature range (<55°C), the reaction rate of the complexation reaction can be reduced. For example, the amount of boron trifluoride gas entering the complexation chamber 100 can be reduced by closing or partially closing the inlet valve 121, or methanol can be introduced into the complexation chamber 100 through the liquid inlet pipe 130 and the liquid inlet / outlet pipe 135.

[0045] The complexation reaction is exothermic. As the reaction proceeds, the temperature inside the complexation chamber 100 rises slowly. Because the complexation container 10 has a slender structure and the packing 11 inside prevents the accumulation of reaction heat, the heat is dispersed. Thus, some of the reaction heat inside the complexation chamber 100 and the heat generated by the circulating pump 133 are dissipated through heat exchange with the external environment via the outer wall of the complexation container 10. The remaining heat is used to heat the liquid. At higher temperatures, the temperature rise is very slow with minimal fluctuations. When the temperature measured by the temperature measuring element 140 exceeds the aforementioned temperature range, the temperature inside the complexation chamber 100 can be lowered by reducing the reaction rate of the complexation reaction. The temperature measuring element 140 can be a temperature sensor.

[0046] The liquid level in the complexing chamber 100 is measured by the liquid level measuring element 141, so that the inlet / outlet liquid assembly 13 adjusts the amount of liquid in the complexing chamber 100 according to the measured liquid level data, preventing the circulation pump 133 from drying out. The liquid level measuring element 141 can form a liquid level measuring chamber 1410 communicating with the complexing chamber 100. The liquid level measuring chamber 1410 is provided with a scale so that the liquid level can be read. In some embodiments, such as Figure 3 As shown, a drain valve 19 can be installed below the liquid level measuring device 141. By opening the drain valve 19, the waste liquid in the liquid level measuring chamber 1410 can be discharged to avoid affecting the next reaction process.

[0047] The pressure in the complexing chamber 100 is measured by pressure measuring element 142 to determine whether the pressure in the complexing chamber 100 needs to be adjusted. Pressure measuring element 142 can be a pressure transmitter.

[0048] In some embodiments, such as Figure 3 As shown, the complexing device 1 may include an vent 16. During the initial water pressure test, cleaning, and other processes, the vent 16 is opened to prevent residual air at the top of the complexing chamber 100 from being unable to escape. During the complexing process, when the pressure inside the complexing chamber 100 is too high, the vent 16 is opened to reduce the pressure inside the complexing chamber 100.

[0049] In some embodiments, the peripheral wall of the complexing container 10 located below the packing 11 forms an observation window 15 for observing the complexation of materials. In some embodiments, the observation window 15 adopts a high-sealing structure to ensure the sealing performance of the complexing chamber 100, so as to prevent air from entering the complexing chamber 100 and reacting with the gaseous medium to generate acidic substances, causing corrosion damage to the equipment. At the same time, the high sealing performance can ensure the purity of the boron trifluoride-methanol complex.

[0050] In some embodiments, see Figure 5 and Figure 6 , Figure 5 This is a schematic diagram of the esterification apparatus according to an embodiment of this application. Figure 6 This is a cross-sectional view of an esterification apparatus according to an embodiment of this application. The esterification apparatus 2 may include: an esterification container 20, a heating element 21, and a stirring assembly 22; the esterification container 20 forms an esterification chamber 200 and an inlet 201, a feed inlet 202, and a discharge outlet 203 communicating with the esterification container 20. The inlet 201 is used to introduce a boron trifluoride-methanol complex into the esterification chamber 200, and the feed inlet 202 is used to introduce a solid defluorinating agent into the esterification chamber 200, so that the boron trifluoride-methanol complex and the solid defluorinating agent undergo an esterification reaction in the esterification chamber 200 to generate trimethyl borate and solid byproducts. The discharge outlet 203 is used to discharge the reacted material in the esterification chamber 200 to the outside; the heating element 21 is configured to heat the esterification chamber 200 and maintain a stable temperature inside the esterification chamber 200; the stirring assembly 22 is used to stir the material in the esterification chamber 200 to make the material uniformly mixed.

[0051] In the embodiments of this application, the heating element 21 heats the esterification chamber 200 and maintains a stable temperature within the esterification chamber 200, enabling the esterification reaction to proceed at a relatively constant reaction temperature, which is beneficial for maintaining the smooth progress of the esterification reaction. The stirring component 22 stirs the materials within the esterification chamber 200, ensuring uniform mixing of the materials, increasing the contact area of ​​the materials, and preventing local concentration of the defluorinating agent that could lead to incomplete reaction. This accelerates the esterification reaction process, resulting in the acquisition of high-purity trimethyl borate, which can then be used to prepare nuclear-grade boric acid.

[0052] The solid byproduct is fluoride. When the solid defluorinating agent is calcium oxide, the solid byproduct is calcium fluoride.

[0053] In some embodiments, such as Figure 5 As shown, the esterification chamber 200 is a sealed chamber, which allows the material to be processed in a tightly sealed chamber that is completely isolated from the external environment, thereby obtaining borate ester compounds with high purity.

[0054] In some embodiments, such as Figure 5and Figure 6 As shown, the heating element 21 can form an annular heating chamber 210 together with the esterification container 20 on the radially outer side of the esterification container 20. The heating chamber 210 is used to receive the flowing heating medium to heat the esterification container 20 using the heating medium.

[0055] In this embodiment, the heating element 21 and the esterification container 20 together form an annular heating chamber 210, allowing the heating medium entering the heating chamber 210 to flow directly over the surface of the esterification container 20. This improves the heating effect on the esterification container 20 and promotes uniform heating, preventing localized overheating during heating. The heating chamber 210 utilizes the flowing heating medium as a heat source, resulting in a more stable temperature and further ensuring temperature stability within the esterification chamber 200.

[0056] In some embodiments, such as Figure 5 As shown, the heating element 21 can form a heating medium inlet 211 and a heating medium outlet 212 that communicate with the heating chamber 210. The heating medium enters the heating chamber 210 through the heating medium inlet 211 to heat the esterification container 20, and flows out through the heating medium outlet 212 after heating is completed.

[0057] In some embodiments, such as Figure 6 As shown, the heating chamber 210 can be divided into a spiral channel by the partition 213. The heating medium flows in the spiral channel, which can extend the flow path of the heating medium in the heating chamber 210, fully transfer heat to the esterification container 20, and improve the heat transfer efficiency.

[0058] In some embodiments, such as Figure 6 As shown, the esterification apparatus 2 may also include a temperature measuring element 23, which is configured to measure the temperature of the esterification chamber 200, so as to adjust the temperature of the heating medium according to the temperature measured by the temperature measuring element 23, so as to stabilize the temperature of the esterification chamber 200.

[0059] In some embodiments, the temperature and flow rate of the heating medium in the heating chamber 210 can be determined based on the temperature measured by the temperature measuring element 23 and the reaction temperature, thereby controlling the temperature in the esterification chamber 200 to maintain the smooth progress of the esterification reaction.

[0060] The measuring end of the temperature measuring element 23 can be located at the bottom of the esterification chamber 200 to measure the temperature of the material inside the esterification chamber 200, so as to more accurately determine the actual temperature of the material.

[0061] In some embodiments, the temperature range of the heating medium can be 65-75°C to maintain the temperature inside the esterification chamber 200 at 60±1°C.

[0062] In some embodiments, such as Figure 6 As shown, the stirring assembly 22 includes a stirring element 220 and a stirring auxiliary element 221. The stirring element 220 is used to stir the material, and the stirring auxiliary element 221 is used to increase the mixing effect of the material.

[0063] In this embodiment, the material in the esterification chamber 200 is stirred by the stirring element 220, and the stirring aid 221 is used to increase the turbidity of the material, so that the material can be in more thorough contact and mixed more evenly, thereby improving the reaction efficiency of the esterification reaction.

[0064] In some embodiments, such as Figure 6 As shown, the stirring component 220 may include a drive motor 2201, a stirring shaft 2202, and multiple blades 2203 disposed at the end of the stirring shaft 2202. The drive motor 2201 drives the stirring shaft 2202 to rotate, thereby causing the multiple blades 2203 to rotate. By rotating the blades 2203, the material is stirred, increasing the contact area between the solid defluorinating agent and the liquid complex, allowing the solid defluorinating agent and the liquid complex to react fully, thereby accelerating the reaction rate of the esterification reaction.

[0065] The blade 2203 is designed to lift the material from the bottom to the top when rotating, thereby improving the mixing effect.

[0066] In some embodiments, the agitator 220 may also include a speed reducer, which can reduce the rotational speed and increase the torque, thereby reducing the heat and operating noise generated by the agitation.

[0067] In some embodiments, the agitator 220 may also include a magnetic coupler, and the agitator shaft 2202 is connected to the reducer via the magnetic coupler, thereby ensuring the sealing of the esterification chamber 200.

[0068] In some embodiments, the agitator 220 may be bolted to the esterification container 20 for easy maintenance and disassembly.

[0069] In some embodiments, the drive motor 2201 can achieve variable frequency speed regulation to control the stirring speed of the stirring shaft 2202 according to the needs of the esterification reaction.

[0070] In some embodiments, such as Figure 6 As shown, the stirring aid 221 can be multiple baffles disposed on the circumferential inner wall of the esterification container 20.

[0071] In this embodiment, by setting multiple baffles 221 around the inner wall of the esterification container 20, the stirring effect is increased, and the solid fluoride is prevented from depositing at the bottom of the esterification container 20 during the stirring process, which would result in insufficient contact with the liquid complex and incomplete reaction, thereby improving the efficiency of the esterification reaction.

[0072] Each baffle 221 can be spaced along the inner wall of the esterification container 20.

[0073] In some embodiments, the height direction of the baffle 221 is vertical, the width direction is radial to the esterification container 20, and the lower end face of the baffle 221 is in contact with the bottom wall of the esterification container 20 to enhance the stirring effect.

[0074] In some embodiments, such as Figure 5 As shown, the esterification apparatus 2 may further include a pressure measuring element 24, which is configured to measure the pressure in the esterification chamber 200. In some embodiments, such as Figure 12 As shown, the esterification apparatus 2 may also include an exhaust port 206 communicating with the esterification chamber 200 and an exhaust valve 205 for opening or closing the exhaust port. When the pressure measured by the pressure measuring element 24 is too high, the exhaust valve 205 is opened and exhaust is released through the exhaust port 206 to reduce the pressure in the esterification chamber 200 to the pressure value required for the reaction, thereby ensuring the smooth progress of the esterification reaction.

[0075] In some embodiments, the pressure measuring element 24 may be a pressure gauge.

[0076] The pressure measuring element 24 can be disposed on top of the esterification container 20.

[0077] In some embodiments, the esterification apparatus 2 may further include a safety valve 25, which is configured to automatically release pressure when the pressure in the esterification chamber 200 exceeds a threshold, so as to avoid the safety hazards caused by overpressure to the esterification container 20 itself and the reaction process during the reaction, thereby ensuring the safety of the reaction process.

[0078] In some embodiments, such as Figure 5 As shown, the esterification apparatus 2 may also include a conductivity measuring element 26, which is configured to measure the conductivity of the esterification reactants in the esterification chamber 200, so as to determine whether the esterification reaction has ended based on the conductivity measured by the conductivity measuring element 26.

[0079] In this embodiment, the conductivity within the esterification chamber 200 is measured by the conductivity measuring device 26. When the conductivity measured by the conductivity measuring device 26 reaches a specified value, the esterification reaction is determined to be complete.

[0080] Furthermore, the conductivity measured by the conductivity measuring device 26 can be used to determine whether the mixture needs to be purified before entering the next process. If the conductivity measured by the conductivity measuring device 26 exceeds the threshold, it indicates that impurities are mixed in the material, and the esterified mixture needs to be purified.

[0081] In some embodiments, such as Figure 5As shown, the peripheral wall of the esterification container 20 located above the heating element 21 can form an observation window 27 for observing the esterification of the material.

[0082] In this embodiment, the liquid level and reaction status in the esterification chamber 200 can be observed through the observation window 27, thereby allowing the feeding rate to be adjusted according to the reaction status.

[0083] In some embodiments, the observation window 27 employs a high-sealing structure to ensure the airtightness of the esterification container 20, thereby ensuring the purity of the esterified product generated in the reaction. The observation window 27 can be positioned above the heating element 21 so as not to affect the uniform heating of the esterification container 20 by the heating element 21.

[0084] In some embodiments, such as Figure 6 As shown, the esterification apparatus 2 may also include a vacuum port 204, which is located on the esterification container 20 and connected to a vacuum device at the other end to evacuate the esterification container 20, thereby ensuring a high cleanliness environment in the esterification chamber 200 before the material enters and reducing impurities.

[0085] In some embodiments, see Figure 7 and Figure 8 , Figure 7 This is a schematic diagram of the structure of a hydrolysis crystallization apparatus according to an embodiment of this application. Figure 8 This is a cross-sectional view of a hydrolysis crystallization apparatus according to an embodiment of this application. The hydrolysis crystallization apparatus may include: a container body 30, a circulating heating assembly 31, a flow guide 32, a stirring assembly 33, a crystal collecting assembly 34, and a steam collecting assembly 35.

[0086] The container body 30 is configured to form a hydrolysis crystallization chamber 300 and a feed inlet 301 in fluid communication with the hydrolysis crystallization chamber 300. The feed inlet 301 is used to supply material to the hydrolysis crystallization chamber 300 so that the material undergoes a hydrolysis reaction in the hydrolysis crystallization chamber 300 to generate solid hydrolysis products and liquid hydrolysis products, and to crystallize the solid hydrolysis products. The circulating heating component 31 is used to allow the material in the hydrolysis crystallization chamber 300 to flow out of the hydrolysis crystallization chamber 300 and to circulate it back to the hydrolysis crystallization chamber 300 after heating. The guide component 32 is disposed in the hydrolysis crystallization chamber 300 to form a guide chamber 3212, the top and bottom of which are in communication with the hydrolysis crystallization chamber 300.

[0087] See Figure 12The stirring assembly 33 is configured to stir the material in the guide chamber 3212 so that the material in the guide chamber 3212 can flow upward to the top of the guide chamber 3212 and enter the hydrolysis crystallization chamber 300, and then flow downward to the bottom of the hydrolysis crystallization chamber 300, and then return to the guide chamber 3212 from the bottom of the guide chamber 3212; part of the material at the bottom of the hydrolysis crystallization chamber 300 can flow downward into the crystal collecting assembly 34, wherein the material with a crystal size smaller than the threshold returns to the bottom of the hydrolysis crystallization chamber 300 and enters the guide chamber 3212, and the remaining material is retained in the crystal collecting assembly 34; the steam collecting component 35 is used to receive the steam at the top of the hydrolysis crystallization chamber 300, condense it into liquid and collect it.

[0088] In this embodiment, the material is heated by flowing out of the hydrolysis crystallization chamber 300 through the circulating heating component 31. After the material is heated to the required reaction temperature, it is returned to the hydrolysis crystallization chamber 300, thereby achieving circulating heating of the material. A guide chamber 3212 is formed by setting the guide component 32. When the material in the guide chamber 3212 is stirred by the stirring component 33, the material in the guide chamber 3212 can flow upward to the top of the guide chamber 3212 and enter the hydrolysis crystallization chamber 300. After flowing downward to the bottom of the hydrolysis crystallization chamber 300, it returns to the guide chamber 3212 from the bottom. Through the above-mentioned circulating heating of the material and the circulating flow of the material inside and outside the guide chamber 3212, it is beneficial to make the material mix more uniformly, thereby making the material temperature more uniform and accelerating the hydrolysis process. It is also beneficial to the gradual nucleation and growth of particles into crystallization, thus improving the crystallization efficiency.

[0089] Furthermore, under the stirring action of the stirring component 33, some material at the bottom of the hydrolysis crystallization chamber 300 flows downward into the crystal collecting component 34. Material with a crystal size smaller than the threshold value can return to the bottom of the hydrolysis crystallization chamber 300 and enter the guiding chamber 3212, while the remaining material is retained in the crystal collecting component 34. This ensures that crystals meeting the size requirements are retained in the crystal collecting component 34, enabling control over crystal size and obtaining crystals with uniform particle size. In addition, the steam at the top of the hydrolysis crystallization chamber 300 is condensed into liquid and collected by the steam collecting component 35, which helps reduce the amount of liquid material in the material, thus facilitating the crystallization of hydrolysis products and enabling the recovery and utilization of the material.

[0090] Therefore, the hydrolysis crystallization chamber 300 and crystal collection assembly 34 of this application are particularly suitable for the process of hydrolysis and recrystallization of materials.

[0091] In some embodiments, such as Figures 8 to 10As shown, the crystal collection assembly 34 may include: a collection body 340 and a separator 341. The collection body 340 forms a collection cavity 3401 and a plurality of return through holes 3402 for connecting the collection cavity 3401 and the hydrolysis crystallization chamber 300. The separator 341 is disposed in the collection cavity 3401 and forms a separator 3410 and a bottom through hole 3415 and a plurality of upper through holes 3411 for connecting the separator 3410 and the collection cavity 3401. Some material at the bottom of the hydrolysis crystallization chamber 300 can enter the separator 3410. Material with a grain size less than or equal to the inner diameter of the upper through-hole 3411 in 3410 can enter the collection chamber 3401 through multiple upper through-holes 3411 under the action of centrifugal force, and return to the bottom of the hydrolysis crystallization chamber 300 through multiple return through-holes 3402. The remaining material in the separation chamber 3410 falls into the collection chamber 3401 through the bottom through-hole 3415. The separator 341 is also configured such that when the remaining material flows downward, the light fluid can also flow upward along the inner wall and enter the collection chamber 3401 through the upper through-hole 3411.

[0092] In this embodiment, the crystal grains formed by crystallization enter the separation chamber 3410 through the bottom of the hydrolysis crystallization chamber 300. Under the action of the centrifugal force provided by the stirring assembly 22, the crystal grains with a size smaller than or equal to the inner diameter of the upper through hole 3411 can enter the collection chamber 3401 through the upper through hole 3411 of the separator 341, and further enter the bottom of the hydrolysis crystallization chamber 300 through the return through hole 3402. Under the action of the stirring assembly 22, they enter the guide chamber 3212 upwards to continue crystallizing during the flow until the crystal grain size is larger than the inner diameter of the upper through hole 3411. Then, they flow downwards in the separation chamber 3410 and finally fall into the collection chamber 3401 through the bottom through hole 3415. During the downward flow of the material, the light fluid (i.e., crystals and liquids with small crystal grain size) flows upwards along the inner wall of the separation chamber 3410 and enters the collection chamber 3401 through the upper through hole 3411, thereby ensuring that the collected crystal grain size is uniform and improving the recovery rate of liquid materials. Furthermore, the aforementioned arrangement of the crystal collecting component 34 facilitates the return of material entering the separation chamber 3410 to the hydrolysis crystallization chamber 300 during the hydrolysis process, preventing material accumulation within the chamber and thus promoting a more thorough hydrolysis reaction. The structure of the crystal collecting component 34 of this application is particularly suitable for processes involving prior hydrolysis followed by crystallization, ensuring both rapid hydrolysis and crystallization processes simultaneously.

[0093] In some embodiments, the upper through hole 3411 forms a circle along the circumference of the collection cavity 3401 to ensure that the material enters the separation cavity 3410 evenly.

[0094] In some embodiments, such as Figures 9 to 11As shown, the separator 341 may include a conical cylindrical member 3412, a partition member 3413, and a bowl-shaped member 3414. The conical cylindrical member 3412, the partition member 3413, and the bowl-shaped member 3414 together form a separation chamber 3410. The top opening of the conical cylindrical member 3412 is larger than the bottom opening, and the top opening of the conical cylindrical member 3412 communicates with the hydrolysis crystallization chamber 300. The upper part of the conical cylindrical member 3412 forms multiple upper through holes 3411 that communicate with the collection chamber 3401. The partition member 3413 is disposed below the multiple upper through holes 3411 of the conical cylindrical member 3412 to form multiple channels within the conical cylindrical member 3412. The bowl-shaped member 3414 is connected to the bottom opening of the conical cylindrical member 3412. A bottom through-hole 3415 is formed at the bottom; materials smaller than the through-hole in the material entering the conical cylinder 3412 from the top opening can enter the collection chamber 3401 through the through-hole, and the remaining material flows downward through multiple channels to enter the bowl-shaped part 3414, and enters the collection chamber 3401 through the bottom through-hole 3415; when the remaining material flows downward, the light fluid can flow upward along the inner wall of the bowl-shaped part 3414 and the conical cylinder 3412 and enter the collection chamber 3401 through multiple upper through-holes 3411.

[0095] In this embodiment, the material at the bottom of the hydrolysis crystallization chamber 300 can enter the separation chamber 3410 through the top opening of the conical cylinder 3412. The smaller material entering the upper part of the separation chamber 3410 enters the collection chamber 3401 through the upper through hole 3411, and then returns to the hydrolysis crystallization chamber 300 for recrystallization through the return through hole 3402. As the larger material spirals down along the inner wall of the conical cylinder 3412, the bowl-shaped part 3414 helps to reduce the turbulence and resistance generated at the abrupt cross section, allowing the lighter material entering the bowl-shaped part 3414 to flow upward and enter the collection chamber 3401 through the upper through hole 3411. By using the separator 3413 to form multiple channels in the conical cylinder 3412, the material flowing into the separation chamber 3410 can be diverted, avoiding local concentration of material flowing into the separation chamber 3410 and causing blockage, thereby ensuring its smooth flow into the bowl-shaped part 3414.

[0096] In some embodiments, the separator 3413 is located on the upper part of the conical cylinder 3412 and below the upper through hole 3411, so as not to affect the small-sized material from leaving the separation chamber 3410 quickly through the upper through hole 3411 after entering the separation chamber 3410; and it also facilitates the material flowing downward along the separator 3413 to slide slowly downward and the small-sized material to slide slowly upward during the rotation process, thereby ensuring that the material flowing out from the bottom through hole 3415 is of uniform size.

[0097] In some embodiments, the separator 3413 may be two plates arranged at opposite ends to divide and form four channels within the conical cylinder 3412.

[0098] In some embodiments, such as Figure 10 As shown, the bowl-shaped component 3414 includes a cylindrical section 34141 and a smooth transition section 34142. A bottom through hole 3415 is formed on the radially inner periphery of the bottom of the smooth transition section 34142. This arrangement increases the flow path of the fluid, allowing the lightweight fluid to flow upward along the inner wall of the bowl-shaped component 3414. This prevents the material from failing to return to the hydrolysis crystallization chamber 300 during hydrolysis, and also prevents small-sized crystals from failing to return to the hydrolysis crystallization chamber 300 during crystallization, thus helping to ensure the uniformity of the crystal grains.

[0099] In some embodiments, such as Figure 9 and Figure 10 As shown, the collecting body 340 may include: a cylindrical component 3403, a bottom plate 3404 that closes the lower end of the cylindrical component 3403, and a top plate 3405 in the annular region between the closed cylindrical component 3403 and the separating component 341. The top plate 3405 is connected to the lower end of the container body 30. The top plate 3405 forms a plurality of return through holes 3402 that communicate with the hydrolysis crystallization chamber 300. The bottom plate 3404 forms a channel 34040 for crystal discharge.

[0100] In this embodiment, by providing a bottom plate 3404 at the lower end of the closed cylindrical component 3403 and a top plate 3405 in the annular region between the closed cylindrical component 3403 and the separator 341, sealing can be ensured, thereby ensuring the purity of the crystal grains obtained from crystallization. By forming multiple return through holes 3402 on the top plate 3405 that communicate with the hydrolysis crystallization chamber 300, the lightweight material with small crystal grains can enter the hydrolysis crystallization chamber 300 for recrystallization through the multiple return through holes 3402, thereby realizing material circulation, improving material utilization, and avoiding material waste.

[0101] In some embodiments, the top plate 3405 forms an opening with the same size as the top opening of the tapered cylinder 3412, and the tapered cylinder 3412 is connected to the periphery of the opening of the top plate 3405.

[0102] In some embodiments, the return through-hole 3402 forms a ring around the radially outer side of the tapered cylinder 3412 to allow material to return uniformly to the hydrolysis crystallization chamber 300.

[0103] In some embodiments, the top plate 3405 may also form a connecting through hole 3406 through which fasteners pass to connect the collecting body 340 to the lower part of the first conical cylinder 303, thereby ensuring a seal.

[0104] In one embodiment of this application, such as Figure 8 As shown, the container body 30 may include: a first cylindrical tube 302 and a first conical tube 303 connected to the lower end of the first cylindrical tube 302, wherein the size of the top opening of the first conical tube 303 is larger than the size of its bottom opening; the guide member 32 may include: a second cylindrical tube 320 and a second conical tube 321 connected to the lower end of the second cylindrical tube 320, wherein the size of the top opening of the second conical tube 321 is larger than the size of its bottom opening; wherein, the first conical tube 303 forms a heating material inlet 3210, and the first cylindrical tube 302 forms a heating material outlet 3211, wherein the material in the hydrolysis crystallization chamber 300 enters the circulating heating assembly 31 through the heating material outlet 3211, and returns to the hydrolysis crystallization chamber 300 through the heating material inlet 3210 after being heated.

[0105] In this embodiment, by making the top opening size of the second conical cylinder 321 larger than its bottom opening size, it is beneficial for the material at the bottom of the hydrolysis and crystallization chamber 300 to flow upward along the second conical cylinder 321 under the action of the stirring assembly 22 during the hydrolysis and crystallization processes, thereby reducing the content of light materials that also enter the separation chamber 3410 at the bottom of the hydrolysis and crystallization chamber 300. By making the top opening size of the first conical cylinder 303 larger than its bottom opening size, the material can be concentrated and flow to the bottom of the hydrolysis and crystallization chamber 300 to participate in the circulation.

[0106] By forming a heating material inlet 3210 in the first conical cylinder 303 and a heating material outlet 3211 in the first cylindrical cylinder 302, the material enters the circulating heating assembly 31 from the heating material outlet 3211, is heated, and then returns from the heating material inlet 3210 to the hydrolysis and crystallization chamber 300 for hydrolysis and crystallization. This continuous circulation continuously heats the material, enabling it to reach the temperature required for hydrolysis and crystallization, thereby improving hydrolysis efficiency and crystallization stability.

[0107] In some embodiments, the crystal collecting assembly 34 is connected to the first conical cylinder 303 and closes the bottom opening of the first conical cylinder 303. Specifically, the top plate 3405 is connected to the first conical cylinder 303 and closes the bottom opening of the first conical cylinder 303.

[0108] In some embodiments, the temperature of the material is maintained at 53-57°C during the hydrolysis process.

[0109] In some embodiments, the temperature of the material is maintained at 73-77°C during the crystallization process.

[0110] In some embodiments, such as Figure 2As shown, the heating material inlet 3210 can face the outer wall of the second conical cylinder 321, allowing the material returning from the heating material inlet 3210 to flow towards the outer wall of the second conical cylinder 321. Because the material returning from the heating material inlet 3210 can flow towards the outer wall of the second conical cylinder 321, when the material circulating downwards within the hydrolysis crystallization chamber 300 mixes with the material returning from the heating material inlet 3210, heat can be diffused more evenly within the material. Furthermore, the material returning from the heating material inlet 3210 flowing towards the outer wall of the second conical cylinder 321 allows the outer wall of the second conical cylinder 321 to guide the material flow, resulting in a more stable flow rate and avoiding interference with the upward and downward flow of material at the bottom of the hydrolysis crystallization chamber 300; it also improves the material mixing effect and promotes uniform material temperature.

[0111] In some embodiments, the axis of the heating material inlet 3210 intersects with the outer wall of the second conical cylinder 321, so that the material returned from the heating material inlet 3210 can flow to the outer wall of the second conical cylinder 321. This not only utilizes the outer wall of the second conical cylinder 321 to guide the material, but also helps to improve the material mixing effect and make the material temperature more uniform.

[0112] In some embodiments, such as Figure 8 As shown, the container body 30 may further include multiple baffles 304, which are spaced apart along the circumference of the first cylindrical member 302 on the inner wall of the first cylindrical member 302. In this embodiment, by spaced apart multiple baffles 304 along the circumference of the first cylindrical member 302 on the inner wall of the first cylindrical member 302, the stirring effect is increased, and the material is prevented from settling at the bottom of the hydrolysis and crystallization chamber 300 during the stirring process, which would lead to insufficient hydrolysis and crystallization, thereby improving the efficiency of hydrolysis and crystallization.

[0113] In some embodiments, such as Figure 8 As shown, the lower end face of the baffle 304 is an inclined surface 3040 that matches the inner wall of the first conical cylinder 303, so as to connect with the inner wall of the first conical cylinder 303, which is conducive to further increasing the turbidity effect and improving the hydrolysis and crystallization efficiency.

[0114] In some embodiments, such as Figure 8 As shown, the circulating heating assembly 31 may include: a circulating pipeline 310, a circulating pump 311, and a heat exchanger 312; the circulating pipeline 310 is connected to the heating material inlet 3210 and the heating material outlet 3211; the circulating pump 311 is used to drive the material from the heating material outlet 3211 into the circulating pipeline 310, exchange heat with the heat exchanger 312 and be heated, and return to the heating material inlet 3210 after heat exchange.

[0115] In this embodiment, the circulating pump 311 drives the material from the heated material outlet 3211 into the circulating pipeline 310, where it exchanges heat with the heat exchanger 312 and then returns to the hydrolysis crystallization chamber 300. This enables the material to be circulated and heated, making the material temperature in the hydrolysis crystallization chamber 300 more uniform. This avoids insufficient reaction due to localized excessively high or low temperatures of the material, thereby improving the efficiency of hydrolysis and crystallization. It also enhances the stirring effect of the material in the hydrolysis crystallization chamber 300.

[0116] Water can be used as the heat exchange medium of heat exchanger 312 to transfer the heat of the water to the material.

[0117] In some embodiments, such as Figure 8 As shown, the steam collection device 35 may include: an outlet pipe 350, a condenser 351, and a receiving container 352; the container body 30 forms an outlet, the outlet pipe 350 is used to connect the outlet and the condenser 351, the condenser 351 is used to condense the steam to form a liquid; the receiving container 352 is disposed below the condenser 351, and the condensed liquid flows into the receiving container 352 under the action of gravity and is collected.

[0118] In this embodiment, the outlet and the condenser 351 are connected by the outlet pipe 350, so that steam flows out from the outlet and enters the condenser 351 through the outlet pipe 350. The condenser 351 condenses the steam into liquid. By placing the collection container below the condenser, the condensed liquid enters the collection container under the action of gravity, and the liquid can be recovered without applying additional force, so that the recovered liquid can be recycled to avoid waste. At the same time, reducing the liquid content in the hydrolysis crystallization chamber 300 is beneficial to accelerating the crystallization rate.

[0119] In some embodiments, the condenser 351 can condense steam by exchanging heat with the steam using a heat exchange medium.

[0120] In some embodiments, such as Figure 8 As shown, the stirring assembly 33 may include a drive motor 330, a stirring shaft 331, and multiple blades 332 disposed at the end of the stirring shaft 331. The drive motor 330 drives the stirring shaft 331 to rotate, thereby causing the multiple blades 332 to rotate. When the blades 332 rotate, they can drive the material to flow upward. In this embodiment, by providing multiple blades 332 at the end of the stirring shaft 331, when the drive motor 330 drives the stirring shaft 331 to rotate, it can drive the multiple blades 332 to rotate, thereby enabling the material to fully hydrolyze and crystallize and accelerating the hydrolysis and crystallization rate.

[0121] In some embodiments, the stirring assembly 33 may further include a speed reducer, which can reduce the rotational speed and increase the torque, thereby reducing the heat and operating noise generated by stirring.

[0122] In some embodiments, the stirring assembly 33 may also include a magnetic coupler, through which the stirring shaft 331 is connected to the reducer, thereby ensuring the sealing of the hydrolysis crystallization chamber 300.

[0123] In some embodiments, the stirring assembly 33 is connected to the container body 30 by bolts, which facilitates maintenance and disassembly.

[0124] In some embodiments, the hydrolysis crystallization apparatus 3 may also include a vacuum port 306, through which a vacuum device is used to evacuate the hydrolysis crystallization chamber 300, thereby ensuring a high cleanliness environment in the hydrolysis crystallization chamber 300 before the material enters and reducing impurities.

[0125] In some embodiments, the hydrolysis crystallization apparatus 3 may further include a temperature measuring element 38, which is disposed on the container body 30 and is used to measure the temperature of the mixed materials in the hydrolysis crystallization chamber 300. When the measured temperature is not within the temperature range required for the reaction, the circulating heating component 31 is controlled to keep the entire reaction process within a stable temperature range, thereby ensuring the smooth progress of hydrolysis and crystallization.

[0126] In some embodiments, the hydrolysis crystallization apparatus 3 may further include a pressure measuring element 39 for measuring the pressure within the hydrolysis crystallization chamber 300.

[0127] In some embodiments, the pressure measuring element 39 may be a pressure gauge. The pressure measuring element 24 may be disposed at the top of the hydrolysis crystallization chamber 300.

[0128] In some embodiments, the hydrolysis crystallization apparatus 3 may further include a safety valve 305, which is configured to automatically release pressure when the pressure in the hydrolysis crystallization chamber 300 exceeds a threshold, so as to avoid safety hazards to the container body 30 itself and the reaction process caused by overpressure during the reaction, thereby ensuring the safety of the reaction process.

[0129] In some embodiments, the hydrolysis crystallization apparatus 3 may further include a conductivity measuring element 37, which is disposed on the container body 30. The conductivity measuring element 37 monitors the conductivity value of the mixed materials. When the conductivity no longer changes significantly, the hydrolysis reaction is considered to be complete.

[0130] In some embodiments, conductivity measuring element 37 may be a conductivity meter.

[0131] In some embodiments, the hydrolysis crystallization apparatus 3 may also include a sight glass 36, which is disposed on the container body 30. The sight glass 36 is used to observe the hydrolysis reaction and liquid level in the hydrolysis crystallization chamber 300, thereby enabling the feeding to be adjusted according to the reaction.

[0132] In some embodiments, the sight glass 36 employs a high-sealing structure to ensure the sealing of the hydrolysis crystallization chamber 300, thereby ensuring the purity of the crystal grains generated by crystallization.

[0133] In some embodiments, the hydrolysis crystallization apparatus 3 may further include a discharge valve 307 disposed at the channel 34040. After crystallization is completed, the discharge valve 307 is opened to collect the crystals in the collection chamber 3401 into the container.

[0134] In some embodiments, the hydrolysis crystallization apparatus is a sealed device, which allows the material to react in a tightly sealed container that is completely isolated from the outside world, thereby improving the purity of the crystal.

[0135] In some embodiments, the feed inlet 301 is used to supply the material to be hydrolyzed into the hydrolysis crystallization chamber 300; the hydrolysis crystallization apparatus 3 may also include a hydrolysate inlet 308 for adding a hydrolysate. In such embodiments, the material to be hydrolyzed and the hydrolysate can be added through two separate inlets.

[0136] In some embodiments, the material to be hydrolyzed is trimethyl borate, and the hydrolysing agent can be water.

[0137] Embodiments of this application also provide a hydrolysis crystallization method, implemented using the hydrolysis crystallization apparatus 3 provided in any embodiment of this application. The method includes: providing trimethyl borate and a hydrolyzing agent to a hydrolysis crystallization chamber 300; stirring the material at a first rotational speed using a stirring assembly 33, and heating the material to a first temperature using a circulating heating assembly 31, so that the trimethyl borate and the hydrolyzing agent undergo a hydrolysis reaction in the hydrolysis crystallization chamber 300 to generate boric acid and methanol; then, stirring the material at a second rotational speed using the stirring assembly 33, and heating the material to a second temperature using the circulating heating assembly 31, so that the boric acid crystallizes and the methanol evaporates; activating a steam collector 35 to liquefy the methanol vapor and collect the methanol; wherein the first rotational speed is greater than the second rotational speed, and the first temperature is lower than the second temperature.

[0138] In the embodiments of this application, the hydrolysis and crystallization apparatus 3 can be used to sequentially realize the hydrolysis of the material and the subsequent crystallization process. By controlling the stirring speed and temperature, the stirring speed and the material temperature are made to meet the needs of the hydrolysis reaction and crystallization, respectively, thereby improving the hydrolysis efficiency of trimethyl borate and the purity of the crystal grains. After hydrolysis and crystallization are completed, methanol vapor is collected and liquefied to recover methanol, enabling the methanol to be recycled and avoiding material waste.

[0139] In some embodiments, the first temperature can be 53-57°C; the second temperature can be 73-77°C.

[0140] In some embodiments, during hydrolysis, the material temperature in the hydrolysis crystallization chamber 300 is maintained at around 55°C by using the circulating heating component 31 and the material is stirred by the first rotation speed, which helps to mix the material evenly and thus accelerates hydrolysis.

[0141] In some embodiments, during crystallization, the circulating heating component 31 is used to maintain the material temperature in the hydrolysis crystallization chamber 300 at around 75°C, and a second rotation speed is used for stirring. This is more conducive to nucleation and grain growth, and avoids crystal breakage and fine particle size caused by excessive speed. The second rotation speed can be determined experimentally to avoid excessively slow crystal deposition and uneven particle size.

[0142] In some embodiments, a hydrolyzing agent and trimethyl borate are introduced into the hydrolysis crystallization chamber until the total liquid level is higher than the heating material outlet 3211 to achieve material circulation heating.

[0143] The working process of the hydrolysis crystallization apparatus 3 in this embodiment is as follows: (1) Hydrolysis process: Trimethyl borate is injected into the hydrolysis crystallization chamber 300 through the feed inlet 301. The circulation pump 133 and the stirring assembly 33 are started. The constant temperature water pump is adjusted, and the temperature of the trimethyl borate is heated and maintained at about 55°C using the heat exchanger 312. Deionized water is injected into the hydrolysis crystallization chamber 300 through the hydrolysing agent inlet 308 to accelerate the stirring speed of the blades 332. Under the action of the circulation pump 311, the material flows from the heated material outlet 3211 into the heat exchanger 312 for heat exchange, and then returns to the bottom of the hydrolysis crystallization chamber 300 through the heated material inlet 3210. Under the action of the blades 332, the material in the guide chamber 3212 is pushed out from bottom to top, and passes through the guide assembly 32 and the container body 30. In the annular gap region, some material flows into the heat exchanger 312 for heat exchange; at the bottom of the hydrolysis crystallization chamber 300, some material rises into the guide chamber 3212 region under the push of the blades 332, and some material descends into the separation chamber 3410, and then circulates back to the bottom of the hydrolysis crystallization chamber 300 through the upper through hole 3411 and the return through hole 3402, and enters the guide chamber 3212 for further circulation under the push of the blades 332. The material circulates repeatedly in the hydrolysis crystallization chamber 300, so that the liquid is fully mixed, which can ensure that the material is relatively uniform in all places, which is conducive to the hydrolysis reaction; the conductivity value of the slurry is monitored by a conductivity meter, and when the conductivity no longer changes significantly, the hydrolysis reaction is considered to be complete.

[0144] (2) Crystallization process: Adjust the temperature of the constant temperature water machine, use the heat exchanger 312 to heat the material to about 75°C, reduce the stirring speed of the blade 332 to avoid crystal breakage and fine particle size due to excessive speed, and crystal deposition and uneven particle size due to excessive slowness. Under the action of the circulating pump 311, the material flows from the heated material outlet 3211 into the heat exchanger 312 for heat exchange, and then returns from the heated material inlet 3210 to the bottom of the hydrolysis crystallization chamber 300. Under the action of the blades 332, the material in the guide chamber 3212 is pushed out from bottom to top. Through the annular gap area between the guide member 32 and the container body 30, some of the material flows into the heat exchanger 312 for heat exchange. At the bottom of the hydrolysis crystallization chamber 300, some of the material rises into the guide chamber 3212 area under the push of the blades 332, and some of the material descends into the separation chamber 3410. Among them, the small particles of material are circulated back to the bottom of the hydrolysis crystallization chamber 300 through the upper through hole 3411 and the return through hole 3402, and enter the guide chamber 3212 for continued circulation under the push of the blades 332. Larger crystal particles cannot pass through the upper through hole 3411 and the return through hole 3402 and are deposited at the bottom of the collection chamber 3401. The circulating material continues to circulate repeatedly within the hydrolysis crystallization chamber 300, ensuring thorough mixing of the liquid and guaranteeing relatively uniform supersaturation throughout. At 75°C, methanol continuously evaporates and enters the condenser 351 for collection, while boric acid begins to crystallize. Through continuous circulation, crystal nuclei form and grow, and uniformly sized boric acid crystals gradually accumulate at the bottom of the collection chamber 3401. Once the crystallization reaction is complete, the discharge valve 307 is opened to remove the crystals.

[0145] In some embodiments, the pre-separation device 4 and / or the pre-separation device 4 may be a centrifugal separator.

[0146] In this embodiment, the centrifuge can separate trimethyl borate and solid byproducts. The separated solid exists as solid waste, and the separated liquid is used for further hydrolysis and crystallization.

[0147] In some embodiments, the drying apparatus 6 is configured to dry boric acid by heating it. In this embodiment, heating the boric acid crystals with the drying apparatus 6 evaporates the liquid remaining on the surface of the boric acid crystals, thereby obtaining dried boric acid-10 crystals with higher purity.

[0148] In some embodiments, the drying device 6 can perform single-batch drying operations or batch drying operations.

[0149] In some embodiments, the drying device 6 may be a drying oven.

[0150] Embodiments of this application also provide a method for manufacturing boric acid, implemented using the system provided in any embodiment of this application. The method may include: S1, mixing boron trifluoride with methanol to undergo a complexation reaction to generate a complex; S2, mixing the complex with a solid defluorinating agent to undergo an esterification reaction to generate trimethyl borate and a solid byproduct; S3, separating the trimethyl borate from the solid byproduct; S4, mixing the trimethyl borate with a hydrolyzing agent to undergo a hydrolysis reaction to generate boric acid and methanol, and crystallizing the boric acid; S5, separating the crystallized boric acid from the liquid components; and S6, drying the separated boric acid.

[0151] In this embodiment, since the complexation, esterification, and hydrolysis reactions of the materials are carried out in different devices, it is beneficial to control each reaction process individually, thereby making each reaction more thorough and resulting in higher purity of the prepared nuclear-grade boric acid, which is beneficial for the preparation of nuclear-grade boric acid-10. Furthermore, by connecting the devices in series, the product of the previous device can be directly used as the raw material for the next device, reducing material loss and thus improving the material conversion rate.

[0152] In some embodiments, step S1 may include: S11, providing methanol to the complexing device 1 and allowing the methanol to flow from the bottom to the top of the complexing device 1 for downward circulating spraying; S12, adding boron trifluoride gas to the complexing device 1 above the surface of the methanol to allow the boron trifluoride gas and the methanol liquid to mix countercurrently and undergo a complexing reaction to generate a complex.

[0153] In this embodiment, by circulating and spraying methanol downwards from the top of the complexing device 1, and then introducing boron trifluoride gas above the methanol liquid surface, a countercurrent gas-liquid exchange motion can be achieved, which can increase the contact area between the methanol liquid and the boron trifluoride gas, allowing the methanol and boron trifluoride gas to fully contact each other, thereby improving the reaction efficiency of the complexation reaction.

[0154] In some embodiments, step S2 may include: S21, providing a complex and a solid defluorinating agent to the esterification apparatus; S22, stirring and heating the materials to cause the complex and the solid defluorinating agent to undergo an esterification reaction to generate trimethyl borate and solid byproducts.

[0155] In this embodiment, by stirring and heating the complex and solid defluorinating agent introduced into the esterification device, the complex and solid defluorinating agent can be brought into full contact and kept within a suitable temperature range, thereby accelerating the esterification reaction process.

[0156] In some embodiments, step S4 may include: S41, providing trimethyl borate and a hydrolyzing agent to the hydrolysis crystallization apparatus; S42, stirring the material at a first rotational speed and heating the material to a first temperature to cause the trimethyl borate and the hydrolyzing agent to undergo a hydrolysis reaction to generate boric acid and methanol; S43, after step S42, stirring the material at a second rotational speed and heating the material to a second temperature to cause the boric acid to crystallize and the methanol to evaporate; S44, liquefying the methanol vapor and collecting the methanol; wherein the first rotational speed is greater than the second rotational speed, and the first temperature is lower than the second temperature.

[0157] In this embodiment, by setting different stirring speeds and heating temperatures for hydrolysis and crystallization respectively, the stirring speed and reaction temperature are made to meet the needs of hydrolysis and crystallization respectively, thereby improving the rate of hydrolysis and crystallization and the purity of the crystal grains obtained from crystallization.

[0158] Regarding the embodiments of this application, it should also be noted that, without conflict, the embodiments of this application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0159] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A system for manufacturing boric acid, characterized in that, It includes: Complexation unit, esterification unit, pre-separation unit, hydrolysis crystallization unit, post-separation unit, and drying unit; The complexing device is used to allow boron trifluoride to undergo a complexing reaction with methanol to generate a complex. The esterification device is used to allow the complex to undergo an esterification reaction with a solid defluorinating agent to generate trimethyl borate and solid byproducts. The pre-separation unit is used to separate trimethyl borate from solid byproducts. The hydrolysis crystallization apparatus is used to allow the trimethyl borate and the hydrolyzing agent to undergo a hydrolysis reaction to generate boric acid and methanol, and to crystallize the boric acid. The subsequent separation device is used to separate the crystallized boric acid from the liquid components; The drying device is used to dry the boric acid separated by the subsequent separation device.

2. The system according to claim 1, characterized in that, The complexing device includes: Complexing container, packing material, air inlet assembly, liquid inlet / outlet assembly, and measuring assembly; The complexing container forms a complexing chamber; The packing material is disposed within the complexing chamber; The air intake assembly is configured to deliver boron trifluoride gas into the complexation chamber; The inlet / outlet assembly is configured to deliver methanol liquid to the complexing chamber and circulate and spray the methanol liquid at the top of the complexing chamber, so that the methanol liquid reacts with the boron trifluoride gas in the complexing chamber to form a complex, and the complex is discharged from the complexing chamber. The measuring component is configured to measure the physical parameters of the complexing chamber; The complexing container is configured to dissipate heat from the complexing chamber to the external environment using the surface of the complexing container.

3. The system according to claim 1, characterized in that, The esterification apparatus includes: Esterification container, heating element and stirring assembly; The esterification container forms an esterification chamber and an inlet, a feed inlet, and a discharge outlet connected to the esterification container. The inlet is used to introduce boron trifluoride-methanol complex into the esterification chamber, and the feed inlet is used to introduce a solid defluorinating agent into the esterification chamber, so that the boron trifluoride-methanol complex and the solid defluorinating agent undergo an esterification reaction in the esterification chamber to generate trimethyl borate and solid byproducts. The discharge outlet is used to discharge the reacted material in the esterification chamber to the outside. The heating element is configured to heat the esterification chamber and maintain a stable temperature within the esterification chamber; The stirring assembly is used to stir the materials in the esterification chamber to ensure that the materials are mixed evenly.

4. The system according to claim 1, characterized in that, The hydrolysis crystallization apparatus includes: The container body is configured to form a hydrolysis crystallization chamber and have a feed inlet in fluid communication with the crystallization chamber. The feed inlet is used to supply material to the hydrolysis crystallization chamber so that the material undergoes a hydrolysis reaction in the hydrolysis crystallization chamber to generate solid hydrolysis products and liquid hydrolysis products, and to crystallize the solid hydrolysis products. A circulating heating component is used to allow the material in the hydrolysis crystallization chamber to flow out of the hydrolysis crystallization chamber, and after heating it, return it to the crystallization chamber and repeat the above process. A flow guide is disposed within the hydrolysis crystallization chamber to form a flow guide chamber, wherein the top and bottom of the flow guide chamber are in communication with the hydrolysis crystallization chamber; The stirring assembly is configured to stir the material in the guide chamber, so that the material in the guide chamber can flow upward to the top of the guide chamber and enter the hydrolysis crystallization chamber, flow downward to the bottom of the hydrolysis crystallization chamber, and then return to the guide chamber from the bottom of the guide chamber; A crystal collecting assembly is provided in which a portion of the material at the bottom of the crystallization chamber can flow downward into the crystal collecting assembly, wherein the material with a crystal size smaller than a threshold returns to the bottom of the hydrolysis crystallization chamber and enters the guide chamber, and the remaining material is retained in the crystal collecting assembly. A steam collector is used to receive the steam at the top of the hydrolysis crystallization chamber, condense it into liquid, and collect it.

5. The system according to claim 1, characterized in that, The pre-separation device and / or the pre-separation device is a centrifugal separator.

6. The system according to claim 1, characterized in that, The drying apparatus is configured to dry the boric acid by heating it.

7. A method for manufacturing boric acid, characterized in that, Implemented using the system of any one of claims 1-6, the method comprises: S1. Mix boron trifluoride with methanol to induce a complexation reaction and form a complex. S2. The complex is mixed with a solid defluorinating agent to undergo an esterification reaction to generate trimethyl borate and solid byproducts. S3. Separate trimethyl borate from solid byproducts; S4. The trimethyl borate and the hydrolysant are mixed to undergo a hydrolysis reaction to generate boric acid and methanol, and to crystallize the boric acid. S5. Separate the crystallized boric acid from the liquid components; S6. The separated boric acid is dried.

8. The method according to claim 7, characterized in that, Step S1 includes: S11. Methanol is supplied to the complexing device and the methanol flows from the bottom to the top of the complexing device for downward circulation spraying; S12. Above the surface of methanol, add boron trifluoride gas into the complexing device so that the boron trifluoride gas and methanol are mixed in a countercurrent manner, and a complexing reaction occurs to form a complex.

9. The method according to claim 7, characterized in that, Step S2 includes: S21. The complex and solid defluorinating agent are provided into the esterification apparatus; S22. Stir and heat the material to cause the complex to undergo an esterification reaction with the solid defluorinating agent to generate trimethyl borate and solid byproducts.

10. The method according to claim 7, characterized in that, Step S4 includes: S41. Trimethyl borate and hydrolyzing agent are provided to the hydrolysis crystallization apparatus; S42. Stir the material at the first rotation speed and heat the material to the first temperature so that trimethyl borate and hydrolysate can undergo a hydrolysis reaction to produce boric acid and methanol; S43. After step S42, the material is stirred at a second rotation speed and heated to a second temperature to crystallize boric acid and evaporate methanol. S44. Liquefy methanol vapor and collect methanol; Wherein, the first rotational speed is greater than the second rotational speed, and the first temperature is lower than the second temperature.

Images