A high-purity boric acid preparation equipment

Abstract

This utility model discloses a high-purity boric acid preparation device, belonging to the field of chemical production technology. It includes a reactor shell with multiple partitions fixed inside the reactor shell and equidistantly distributed axially, dividing the inner cavity of the reactor shell into multiple independent chambers. Each independent chamber is equipped with a nitric acid replenishment pipe, a heating coil, a pH meter, and a thermometer. A main shaft penetrates all chambers and is rotatably connected to the through-holes at the center of each partition. Multiple overflow channels are provided within the main shaft, with the inlet of each overflow channel located at the top of the current independent chamber and the outlet extending to the bottom of the next independent chamber. This high-purity boric acid preparation device, by setting multiple partitions within a single reactor to form multiple independent reaction chambers, achieves multi-stage series reaction. Stepwise acid addition avoids the problem of excessively high local concentrations caused by adding nitric acid all at once, and significantly reduces the phenomenon of boric acid encapsulating unreacted borax.

Description

Technical Field

[0001] This utility model belongs to the field of chemical production technology, and in particular relates to a high-purity boric acid preparation equipment. Background Technology

[0002] With the continuous growth in demand for high-purity boric acid in the chemical industry, especially its widespread application in glass manufacturing, pharmaceuticals, and electronics, how to efficiently and stably produce high-purity boric acid has become a focus of industry attention. Boric acid is mainly prepared through the acidolysis reaction of borax and nitric acid. Traditional production methods mostly employ batch acidolysis or multi-reactor series processes. However, with the expansion of production scale and the improvement of product quality requirements, these traditional processes have gradually revealed problems such as low reaction efficiency, high equipment maintenance costs, and unstable product quality, making it difficult to meet the needs of modern chemical production.

[0003] Traditional multi-stage series reactor processes are widely used in boric acid production, but they have significant drawbacks. Single-point acid addition leads to severe localized over-acidification, and boric acid encapsulates unreacted borax, causing the reaction yield to consistently hover below 85%. Furthermore, the inter-stage piping connection method not only increases the risk of nitric acid corrosion and leakage but also affects reaction kinetics due to temperature drops (>5°C) during material transport, further restricting production efficiency and product quality improvement.

[0004] Therefore, we propose a high-purity boric acid preparation device to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to solve the problems in the prior art where single-point acid addition leads to severe local over-acidification and boric acid encapsulates unreacted borax, resulting in low reaction yield. Therefore, this invention proposes a high-purity boric acid preparation device.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A high-purity boric acid preparation device includes a reaction vessel shell, wherein the reaction vessel shell is provided with: Multiple partitions are fixed inside the reactor shell and are equidistant along the axis, dividing the inner cavity of the reactor shell into multiple independent chambers along the axis. Each partition has a through hole in the center, and each independent chamber is equipped with a nitric acid replenishment pipe, a heating coil, a pH monitor and a thermometer. The raw material inlet pipe connects to the uppermost independent chamber; The main shaft runs through all chambers and is rotatably connected to the through holes in the center of each partition. Multiple overflow channels are provided inside the main shaft. The inlet of the overflow channel is located at the top of the current independent chamber, and the outlet extends to the bottom of the next independent chamber. The motor is installed at the bottom of the reactor shell, and its output end is fixedly connected to the main shaft coaxially.

[0007] Preferably, each of the independent chambers is equipped with two sets of anti-back-mixing plates, which divide the independent chamber into an upper push flow zone, a mixing zone, and a lower push flow zone.

[0008] Preferably, the anti-backmixing plate includes an inner positioning ring and an outer positioning ring. The outer positioning ring is fixedly connected to the inner wall of the reactor shell, and the inner positioning ring is rotatably connected to the main shaft. Multiple arc-shaped baffles are provided between the inner and outer positioning rings. The concave surfaces of the baffles are arranged facing each other and staggered, forming an anti-mixing channel between two adjacent baffles.

[0009] Preferably, multiple sets of stirring rods are installed on the side wall of the main shaft, and each set of stirring rods is located in the mixing zone of an independent chamber.

[0010] Preferably, the inlet of the overflow channel is located in the upper push flow zone of the current level independent chamber, and the outlet is located in the lower push flow zone of the next level independent chamber.

[0011] Preferably, at least two partitions are provided, forming at least three independent chambers within the reactor shell.

[0012] Preferably, an overflow pipe is installed at the bottom of the reactor shell, and the inlet of the overflow pipe is located in the upper push flow zone of the lowest independent chamber.

[0013] In summary, the technical effects and advantages of this utility model are as follows: This high-purity boric acid preparation equipment, by setting multiple layers of partitions in a single reactor to form multiple independent reaction chambers (preferably 4-6 stages), achieves multi-stage series reaction. Each stage chamber is independently equipped with a heating plate to control the temperature (95-100℃) and a nitric acid replenishment pipe. The amount of nitric acid added is dynamically allocated according to the reaction progress: 40% is added in the initial stage (for rapid reaction start-up), 40% in the intermediate stage (to maintain the reaction rate), and 20% in the final stage (to precisely adjust the final pH). This stepwise acid addition method avoids the problems associated with traditional methods. The process significantly reduces the problem of excessively high local concentrations caused by the one-time addition of nitric acid, resulting in boric acid coating of unreacted borax. The reaction yield is increased to over 94.5%. The pH of the first-stage reaction chamber is controlled at 5.0-6.0 to prevent clumping caused by rapid acidolysis of borax through a weakly acidic environment. The pH of subsequent chambers is gradually reduced, with the final stage pH controlled at 2.0-3.0 to ensure complete reaction of borax to form boric acid. This gradient pH control strategy solves the problem of local over-acidity in traditional single-point acid addition processes, resulting in a more uniform reaction and higher product purity.

[0014] Compared to traditional multi-stage series processes, this high-purity boric acid preparation equipment eliminates interstage pipeline connections, avoiding heat loss and pipeline corrosion leakage risks during material transportation. It also reduces equipment footprint and investment costs. With the elimination of interstage pipelines, leakage points are reduced to zero, eliminating the risk of nitric acid corrosion leakage. The equipment operates more stably, and maintenance costs are significantly reduced. In addition, the integrated overflow channel design of the main shaft avoids crystallization blockage caused by temperature loss in interstage pipelines, ensuring production continuity. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the internal structure of this utility model; Figure 3 This is a cross-sectional structural diagram of the present invention; Figure 4 This is a schematic diagram of the anti-mixing plate structure in this utility model; Figure 5 for Figure 3 A magnified structural diagram of part A in the middle.

[0016] In the diagram: 1. Reactor shell; 2. Baffle plate; 3. Independent chamber; 4. Main shaft; 41. Stirring rod; 5. Motor; 6. Anti-back-mixing plate; 61. Inner positioning ring; 62. Outer positioning ring; 63. Baffle bar; 64. Anti-mixing channel; 7. Upper push flow zone; 8. Mixing zone; 9. Lower push flow zone; 10. Overflow channel; 11. Nitric acid replenishment pipe; 12. Heating coil; 13. pH meter; 14. Thermometer; 15. Overflow pipe; 16. Raw material inlet pipe. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0018] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0019] Reference Figures 1-5 A high-purity boric acid preparation device includes a reaction vessel shell 1, on which a raw material inlet pipe 16, a main shaft 4, a motor 5, and multiple partitions 2 are provided.

[0020] Multiple baffles 2 are fixed inside the reactor shell 1 and are equidistantly distributed axially, dividing the inner cavity of the reactor shell 1 into multiple independent chambers 3 along the axial direction. The baffles 2 have through holes in the center. Each independent chamber 3 is equipped with a nitric acid replenishment pipe 11, a heating coil 12, a pH monitor 13, and a thermometer 14. Compared with the traditional single-chamber reactor, the design of multiple independent chambers 3 has significant advantages. In the traditional reactor for pure boric acid preparation, the raw materials are mixed and reacted in a single chamber. A single addition of acid leads to local over-acidity, causing boric acid encapsulation and reducing the yield. The multiple independent chambers 3 of this high-purity boric acid preparation equipment can dynamically distribute the amount of nitric acid added according to the reaction progress through the nitric acid replenishment pipes 11 on different independent chambers 3. 40% is added in the initial stage (for rapid reaction start-up), 40% in the intermediate stage (for maintaining the reaction rate), and 20% in the final stage (for precise adjustment of the final pH). This stepwise acid addition method avoids the problem of excessively high local concentration caused by a single addition of nitric acid in the traditional process, significantly reduces the phenomenon of boric acid encapsulating unreacted borax, and increases the reaction yield to over 94.5%.

[0021] The heating coil 12 can precisely adjust the temperature in the independent chamber 3 according to the needs of the reaction, providing a suitable temperature environment for the reaction and ensuring that the reaction can proceed smoothly.

[0022] pH meter 13 can monitor the acidity or alkalinity of the material in independent chamber 3 in real time. By monitoring the pH value in real time, the operator can understand the progress of the reaction in a timely manner and adjust the amount of nitric acid or other reaction conditions as needed, so as to ensure that the reaction always proceeds within the optimal pH range.

[0023] The thermometer 14 is used to accurately measure the temperature inside the independent chamber 3. In conjunction with the heating coil 12, the thermometer 14 can feed back the measured temperature data to the control system. The control system adjusts the heating power of the heating coil 12 according to the preset temperature value to achieve precise control of the temperature inside the independent chamber 3, which can effectively improve the efficiency of the reaction and the quality of the product. The control system is existing technology and adopts a programmable PLC controller. Its program setting is a conventional method for those skilled in the art and will not be elaborated on here.

[0024] The main shaft 4 passes through the chamber and is rotatably connected to the through holes in the center of each partition 2, ensuring a good seal between the main shaft 4 and the partition 2. Multiple overflow channels 10 are opened inside the main shaft 4. The inlet of the overflow channel 10 is located at the top of the independent chamber 3 of the current stage, and the outlet extends to the bottom of the next independent chamber 3. The overflow channels 10 realize the interconnection between the independent chambers 3, integrating the multi-stage series process in the reactor shell 1. The material can flow orderly between different independent chambers 3, eliminating the interstage pipeline connection, avoiding heat loss and pipeline corrosion leakage risks during material transportation, and reducing the equipment footprint and investment costs. After eliminating the interstage pipeline, the leakage points are reduced to zero, eliminating the risk of nitric acid corrosion leakage, making the equipment operation more stable and significantly reducing maintenance costs. At the same time, the main shaft integrated overflow channel design avoids the crystallization blockage problem caused by temperature loss in the interstage pipeline, ensuring production continuity.

[0025] Reference Figures 2-3 When the material reaction in the independent chamber 3 reaches a certain level, the material will enter from the top overflow channel 10 inlet and then flow to the bottom of the next level independent chamber 3 through the overflow channel 10. The raw material overflows from the top and enters from the bottom, which can ensure that it has enough residence time in the independent chamber 3 so that the reaction can proceed fully. The material flows in a directional manner through continuous overflow. This flow method allows the material to be fully mixed with the material in the next level chamber when it enters the next level chamber, and to continue the subsequent reaction. The raw material inlet pipe 16 is connected to the uppermost independent chamber 3, and gradually overflows from top to bottom in each level of independent chamber 3, and finally enters the lowermost independent chamber 3. An overflow pipe 15 is installed at the bottom of the reactor shell 1. The inlet of the overflow pipe 15 is located in the upper push flow zone 7 of the lowermost independent chamber 3. After the final reaction is completed in the lowermost independent chamber 3, ensuring that the borax is completely reacted to generate boric acid, it is discharged through the overflow pipe 15 and enters the subsequent crystallization and washing equipment.

[0026] Reference Figures 2-3 At least two baffles 2 are provided, forming at least three independent chambers 3 inside the reactor shell 1. In this embodiment, it is constructed as a four-stage series overflow reactor.

[0027] The high-purity boric acid preparation equipment adopts the following process conditions: First-level independent chamber 3: Borax to mother liquor solid-liquid ratio 1:3, total nitric acid added 40%, temperature 95±1℃, pH=5.5±0.2; Second-level independent chamber 3: 30% of the total nitric acid is added, temperature is 98±1℃, pH=4.0±0.2; Third-level independent chamber 3: 20% total nitric acid supplementation, temperature 100±1℃, pH=3.2±0.2; Fourth-level independent chamber 3: 10% total nitric acid added, temperature 100±1℃, pH=2.5±0.2.

[0028] The motor 5 is installed at the bottom of the reactor shell 1, and its output end is coaxially and fixedly connected to the main shaft 4. Multiple sets of stirring rods 41 are installed on the side wall of the main shaft 4. The motor 5 provides power for the rotation of the main shaft 4, so that the main shaft 4 can drive the stirring rods 41 and other components on it to rotate, thereby improving the reaction rate and mixing effect.

[0029] Reference Figures 2-5 Each independent chamber 3 is equipped with an anti-back-mixing plate 6. Each set of stirring rods 41 is located in the mixing zone 8 of each independent chamber 3, dividing the independent chamber 3 into an upper push flow zone 7, a mixing zone 8, and a lower push flow zone 9. Since the material overflows from the top of the independent chamber 3, the stirring and natural mixing of the material will cause back-mixing. The two sets of anti-back-mixing plates 6 separate the material feed and overflow discharge from the mixing part, reducing the excessive mixing of new and old materials caused by back-mixing. The material is mixed and reacted in the mixing zone 8, and after passing through the anti-back-mixing plate 6, it enters the upper push flow zone 7 to form a horizontal push flow, so that the material after the reaction is completed overflows.

[0030] The inlet of the overflow channel 10 is located in the upper push flow zone 7 of the independent chamber 3 of this stage, and the outlet is located in the lower push flow zone 9 of the next independent chamber 3.

[0031] Reference Figures 2-5 The anti-back-mixing plate 6 includes an inner positioning ring 61 and an outer positioning ring 62. The outer positioning ring 62 is fixedly connected to the inner wall of the reactor shell 1, and the inner positioning ring 61 is rotatably connected to the main shaft 4. This allows the anti-back-mixing plate 6 to be stably installed in the independent chamber 3 without affecting the normal rotation of the main shaft 4. Multiple arc-shaped baffles 63 are arranged between the inner positioning ring 61 and the outer positioning ring 62. The concave surfaces of the baffles 63 face each other and are staggered, forming an anti-mixing channel 64 between adjacent baffles 63. When material flows through the anti-back-mixing plate 6, the arc-shaped baffles 63 obstruct and guide the material. Because the concave surfaces of the baffles 63 face each other and are staggered, the material is forced to change its flow direction when passing through the anti-mixing channel 64, thus forming an orderly flow pattern. This design effectively prevents back-mixing of materials in the independent chamber 3, ensuring the stability of the flow direction and flow state of the material in the upper push flow zone 7, the mixing zone 8, and the lower push flow zone 9.

[0032] Each partition 2 is equipped with a vent valve that connects the upper and lower independent chambers 3. The bottom of the lowest independent chamber 3 is equipped with a vent pipe. When not in use, the residual material in the independent chamber 3 is released to the lower independent chamber 3 through the vent valve, and finally the inside of the reactor shell 1 is emptied through the vent pipe.

[0033] Working principle: Raw materials are fed into the uppermost independent chamber 3 through the raw material inlet pipe 16. The motor 5 is turned on, and the motor 5 drives the main shaft 4 to rotate. The stirring rod 41 on the main shaft 4 rotates accordingly to stir and mix the raw materials. At the same time, nitric acid is added through the nitric acid replenishment pipe 11 corresponding to the first-stage independent chamber 3 to start the reaction. The flow rates of the raw material inlet pipe 16 and the nitric acid replenishment pipe 11 are controlled. The heating coil 12 heats the chamber according to the preset temperature to provide a suitable temperature environment for the reaction. The pH monitor 13 monitors the acidity and alkalinity of the materials in the chamber in real time.

[0034] When the material reaction in the first-stage independent chamber 3 reaches a certain level, the material enters from the top overflow channel 10 inlet and flows through the overflow channel 10 in the main shaft 4 to the bottom of the second-stage independent chamber 3 to replenish nitric acid and continue the reaction. This process continues until the material gradually overflows into the bottommost independent chamber 3 to complete the reaction.

[0035] The controlled reaction parameters are as follows: First-stage independent chamber 3: borax to mother liquor solid-liquid ratio 1:3, total amount of nitric acid added 40%, temperature 95±1℃, pH=5.5±0.2; Second-level independent chamber 3: 30% of the total nitric acid is added, temperature is 98±1℃, pH=4.0±0.2; Third-level independent chamber 3: 20% total nitric acid supplementation, temperature 100±1℃, pH=3.2±0.2; Fourth-level independent chamber 3: 10% total nitric acid added, temperature 100±1℃, pH=2.5±0.2.

Claims

1. A high-purity boric acid preparation device, comprising a reaction vessel shell (1), characterized in that, The reactor shell (1) is provided with: Multiple partitions (2) are fixed inside the reactor shell (1) and are equidistantly distributed along the axis, dividing the inner cavity of the reactor shell (1) into multiple independent chambers (3) along the axis. The partitions (2) have through holes in the center. Each independent chamber (3) is equipped with a nitric acid replenishment tube (11), a heating coil (12), a pH meter (13), and a thermometer (14). The raw material inlet pipe (16) is connected to the uppermost independent chamber (3); The main shaft (4) passes through all chambers and is rotatably connected to the through hole in the center of each partition (2). Multiple overflow channels (10) are provided inside the main shaft (4). The inlet of the overflow channel (10) is located at the top of the independent chamber (3) of this level, and the outlet extends to the bottom of the next level independent chamber (3). The motor (5) is installed at the bottom of the reactor shell (1), and its output end is coaxially fixedly connected to the main shaft (4).

2. The high-purity boric acid preparation equipment according to claim 1, characterized in that, Each of the independent chambers (3) is equipped with two sets of anti-back-mixing plates (6), which divide the independent chambers (3) into an upper push flow zone (7), a mixing zone (8), and a lower push flow zone (9).

3. The high-purity boric acid preparation equipment according to claim 2, characterized in that, The anti-back-mixing plate (6) includes an inner positioning ring (61) and an outer positioning ring (62). The outer positioning ring (62) is fixedly connected to the inner wall of the reactor shell (1). The inner positioning ring (61) is rotatably connected to the main shaft (4). A plurality of arc-shaped baffles (63) are provided between the inner positioning ring (61) and the outer positioning ring (62). The concave surfaces of the baffles (63) are arranged facing each other and interlaced, forming an anti-mixing channel (64) between two adjacent baffles (63).

4. The high-purity boric acid preparation equipment according to claim 2, characterized in that, Multiple sets of stirring rods (41) are installed on the side wall of the main shaft (4), and each set of stirring rods (41) is located in the mixing zone (8) of each independent chamber (3).

5. The high-purity boric acid preparation equipment according to claim 2, characterized in that, The inlet of the overflow channel (10) is located in the upper push flow zone (7) of the independent chamber (3) of this level, and the outlet is located in the lower push flow zone (9) of the next level independent chamber (3).

6. The high-purity boric acid preparation equipment according to claim 1, characterized in that, At least two partitions (2) are provided, forming at least three independent chambers (3) inside the reactor shell (1).

7. The high-purity boric acid preparation equipment according to claim 1, characterized in that, An overflow pipe (15) is installed at the bottom of the reactor shell (1), and the inlet of the overflow pipe (15) is located in the upper push flow zone (7) of the lowest independent chamber (3).

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