Device and method for promoting continuous operation of oxalate precipitation through ultrasonic assistance

Abstract

The invention relates to a device and method for promoting continuous operation of oxalate precipitation through ultrasonic assistance, the device comprises a reactor and a mixer, a stock solution pump and a precipitant pump are respectively connected with the top and the left end of the mixer through pipelines, the mixer is connected with an inlet of the reactor, an outlet of the reactor is connected with an alternate filter, and the alternate filter is connected with a mother liquor storage tank; a nitrate solution and an oxalic acid solution are respectively sent into a mixer for mixing through a stock solution pump and a precipitant pump, and then sent into a reactor for precipitation reaction, slurry is transferred into a filter, and solid-liquid separation is realized through vacuum filtration. The ultrasonic technology is applied to the continuous flow tubular reaction device, formation of oxalate is promoted through the ultrasonic enhancement technology, the reaction liquid mixing effect is further improved, the reaction time is shortened, slurry obtained after reaction is directly filtered, aging time is not needed, and continuous operation of the device is achieved. Meanwhile, the ultrasonic enhancement technology can effectively prevent the pipeline from being blocked, long-term stable operation of the device is achieved, and automatic operation is completed.

Description

Technical Field

[0001] This invention relates to the field of nuclear chemical technology, specifically to an apparatus and method for promoting continuous operation of oxalate precipitation with ultrasound assistance. Background Technology

[0002] In the 1990s, microchannel continuous flow reactor technology was widely used in chemical, energy, environmental, and materials fields. However, in the nuclear chemical industry, very few companies have applied microchannel continuous flow technology to produce highly radioactive nuclear materials. Due to the inherent characteristics of the reaction, continuous flow tubular reactors cannot operate effectively for extended periods, are prone to clogging, require regular pipe cleaning by operators, and cannot be fully automated. Furthermore, the production of solid substances can lead to cumulative blockages within the complex flow channels, making it impossible to improve solution mixing through channel design.

[0003] Ultrasonic enhancement technology utilizes the pressure and shear forces generated by high-frequency sound waves in a liquid to promote chemical reactions. These forces can break chemical bonds in the liquid, making it easier for reactant molecules to interact and form products. Furthermore, ultrasonic enhancement technology helps prevent pipe blockage. By converting ultrasonic transducers into high-frequency mechanical vibrations, cavitation is created in the reaction liquid within the pipe. Numerous tiny vacuum bubbles form in the negative pressure zone of the vibration, while in the positive pressure zone, these tiny bubbles suddenly collapse under pressure. During this collapse, the collisions between liquid molecules generate powerful shock waves, creating instantaneous high pressure that acts on the inner wall of the pipe, causing precipitates to detach from the pipe's inner wall.

[0004] In summary, this invention applies ultrasonic technology to a continuous flow tubular reactor, using ultrasonic enhancement to promote oxalate formation, further shortening the reaction time. The resulting slurry can be directly filtered without aging, enabling continuous operation of the apparatus. Simultaneously, ultrasonic enhancement effectively prevents solid substances from adhering to the inner wall of the pipeline and clogging it, ensuring long-term stable operation and achieving automated operation. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for ultrasonically assisted continuous oxalate precipitation. The ultrasonically assisted apparatus can improve production efficiency and effectively prevent solid substances in pipelines from adhering to the inner wall and causing blockage.

[0006] The technical solution of the present invention is as follows: A device for continuous operation of ultrasonic-assisted oxalate precipitation includes a reactor and a mixer. A raw liquid pump and a precipitant pump are respectively connected to the top and left end of the mixer through pipelines. The mixer is connected to the inlet of the reactor, and the outlet of the reactor is connected to an alternating filter. The alternating filter is connected to a mother liquor storage tank. Nitrate solution and oxalic acid solution are respectively sent to the mixer for mixing by the raw liquid pump and the precipitant pump, and then sent to the reactor for precipitation reaction. The slurry is transferred to the filter, and solid-liquid separation is achieved by vacuum filtration.

[0007] The mixer contains baffles, which are installed vertically inside the mixer. By rotating the baffles, the direction of liquid flow is changed.

[0008] The reactor includes an ultrasonic generator connected to a metal frame and fixed to the top of the metal frame. A clamp is connected to the lower end of the metal frame, and the spiral tube reactor is fixed to the clamp. The ultrasonic generator generates ultrasonic waves, which are conducted through the metal frame to the reaction solution inside the spiral tube reactor. The solution is located inside the spiral tube reactor. The inlet of the spiral tube reactor is connected to a mixer, and the outlet is connected to an alternating filter through a pipeline.

[0009] The spiral reactor is enclosed by heating belts on both the inside and outside.

[0010] An alternating filter consists of two flat-plate filters that are used alternately.

[0011] A method for continuous ultrasound-assisted oxalate precipitation includes the following steps:

[0012] S1: Prepare oxalic acid solution as a precipitant; prepare nitrate solution as the stock solution;

[0013] S2: Nitrate solution and oxalic acid solution are delivered to the mixer by the stock solution pump and the precipitant pump, respectively, and the two solutions are mixed in the mixer;

[0014] S3: The solution in the mixer enters the reactor, and the slurry after the reaction is directly pumped to the alternating filter, where it is vacuum filtered to obtain oxalate solids.

[0015] In S2, the stock solution pump and the precipitant pump provide segmented flow solutions.

[0016] In step S2, the direction of liquid flow is changed by a baffle in the mixer.

[0017] In step S3, the remaining filtrate is sent to the mother liquor storage tank.

[0018] The significant advantages of this invention are as follows: This invention applies ultrasonic technology to a continuous flow tubular reactor, promoting oxalate formation through ultrasonic enhancement, further improving the mixing effect of the reaction solution, shortening the reaction time, and allowing direct filtration of the post-reaction slurry without aging time, thus achieving continuous operation of the device. Simultaneously, ultrasonic enhancement technology effectively prevents pipe blockage, ensuring long-term stable operation of the device and automating its operation. Process exploration using this equipment with ultrasonic assistance revealed that achieving 100% of the maximum ultrasonic power yields the best results. Comparison of ultrasonic frequencies of 20Hz, 40Hz, and 60Hz showed that a frequency of 20Hz yielded the best results. Attached Figure Description

[0019] Figure 1 Schematic diagram of a device for continuous operation of ultrasound-assisted oxalate precipitation;

[0020] Figure 2 Schematic diagram of the mixer;

[0021] Figure 3 Schematic diagram of an ultrasound-assisted continuous flow tubular reactor;

[0022] Figure 4 A three-dimensional view of an ultrasound-assisted continuous flow tubular reactor;

[0023] The markings in the diagram and their corresponding component names are as follows:

[0024] Reactor 1, Mixer 2, Raw material pump 3, Precipitator pump 4, Alternating filter 5, Mother liquor storage tank 6, Baffle 7

[0025] 11. Ultrasonic generator, 12. Metal frame, 13. Clamping plate, 14. Spiral tube reactor. Detailed Implementation

[0026] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0027] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” used in one or more embodiments of this application refers to and includes any or all possible combinations of one or more associated listed items.

[0028] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this application, and similarly, second may also be referred to as first.

[0029] The specific technical content of the present invention will now be described with reference to the accompanying drawings;

[0030] like Figure 1 As shown, an ultrasonic-assisted device for continuous operation of oxalate precipitation includes a reactor 1, a mixer 2, a stock solution pump 3 and a precipitant pump 4 connected to the top and left end of the mixer 2 respectively via pipelines, and the mixer 2 is connected to the inlet of the reactor 1, the outlet of the reactor 1 is connected to an alternating filter 5, and the alternating filter 5 is connected to a mother liquor storage tank 6.

[0031] Nitrate solution and oxalic acid solution are respectively sent to mixer 2 for mixing via raw liquid pump 3 and precipitant pump 4, and then sent to reactor 1 for precipitation reaction. The slurry is then transferred to filter 5, and solid-liquid separation is achieved by vacuum filtration.

[0032] like Figure 2 As shown, the mixer 2 has a baffle 7, which is vertically installed inside the mixer 2 and can rotate. By rotating the baffle 7, the liquid flow direction is changed, and the mixing effect is increased.

[0033] like Figure 3 , 4 As shown, reactor 1 includes an ultrasonic generator 11, which is connected to a metal frame 12 and fastened to the top of the metal frame 12 by bolts. A clamping plate 13 is connected to the lower end of the metal frame 12, and a spiral reactor 14 is fixed to the clamping plate 13. The ultrasonic generator 11 generates ultrasonic waves, which are conducted through the metal frame 12 to the reaction solution inside the spiral reactor 14. The solution is located inside the spiral reactor 14, and the inlet of the spiral reactor 14 is connected to a mixer 2, while the outlet is connected to an alternating filter 5 via a pipeline.

[0034] Specifically, reactor 1 has an inner diameter of 4mm and an outer diameter of 6mm. The pipe material is 316L and the inner wall of the pipe is polished. The spiral tube reactor 14 is wrapped with heating belts on both the inner and outer sides to provide precise heating temperature for reactor 1.

[0035] Specifically, the alternating filter 5 includes two plate filters that are used alternately to achieve continuous operation. The equipment is simple and easy to operate. The slurry in the reactor 1 is pumped into the alternating filter 5, and solid-liquid separation is achieved by vacuum filtration.

[0036] A method for continuous ultrasound-assisted oxalate precipitation includes the following steps:

[0037] S1: Weigh an appropriate amount of oxalic acid and dissolve it in a deionized water solution to prepare 2L of 0.6mol / L oxalic acid solution for later use (i.e., precipitant); prepare 2.0L of nitrate solution with a concentration of 30g / L for later use.

[0038] S2: Nitrate solution (stock solution) and oxalic acid solution (precipitant) are delivered to mixer 2 by stock solution pump 3 and precipitant pump 4 respectively, and the two solutions are mixed in mixer 2;

[0039] Specifically, the stock solution pump 3 and the precipitant pump 4 provide segmented flow solutions, which can effectively prevent clogging during continuous crystallization.

[0040] Specifically, the reaction time of the reactants in the reactor is determined by setting the total flow rate of the raw liquid pump 3 and the precipitant pump 4, and the reaction ratio of nitrate and oxalic acid is determined by setting the flow rate ratio of the raw liquid pump 3 and the precipitant pump 4 respectively.

[0041] Specifically, the mixing effect is enhanced by changing the direction of liquid flow through baffles in the mixer.

[0042] S3: The solution in mixer 2 enters reactor 1, and the slurry after reaction is directly pumped to alternating filter 5, where oxalate solids are obtained by vacuum filtration. The remaining filtrate is sent to mother liquor storage tank 6.

[0043] Example:

[0044] The ultrasonic reactor was started, and the nitrate and oxalic acid feed pumps were adjusted to set the total flow rate of the mixture to 50 ml / min, with a residence time of 2.5 min in the reactor. After precipitation, the slurry was transferred to a flat-plate filter, where solid-liquid separation was achieved through vacuum filtration. Based on the ratio of the actual to the theoretical mass of oxalate, the product conversion rate reached 91.06%. The reaction proceeded smoothly for 4.0 hours, enabling continuous operation of the apparatus.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0046] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0047] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0048] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to better understand and utilize this application.

Claims

1. A device for continuous operation of ultrasound-assisted oxalate precipitation, characterized in that: The system includes a reactor (1), a mixer (2), a raw liquid pump (3), and a precipitant pump (4), which are connected to the top and left end of the mixer (2) respectively through pipelines. The mixer (2) is connected to the inlet of the reactor (1), and the outlet of the reactor (1) is connected to an alternating filter (5). The alternating filter (5) is connected to a mother liquor storage tank (6). The raw liquid pump (3) and the precipitant pump (4) respectively send the nitrate solution and oxalic acid solution to the mixer (2) for mixing, and then send them to the reactor (1) for precipitation reaction. The slurry is transferred into the filter (5), and solid-liquid separation is achieved by vacuum filtration.

2. The device for continuous operation of ultrasound-assisted oxalate precipitation according to claim 1, characterized in that: The mixer (2) contains a baffle (7), which is installed vertically inside the mixer (2). The direction of liquid flow is changed by rotating the baffle (7).

3. The device for continuous operation of ultrasound-assisted oxalate precipitation according to claim 2, characterized in that: The reactor (1) includes an ultrasonic generator (11), which is connected to a metal frame (12) and fixed on the top of the metal frame (12). The lower end of the metal frame (12) is connected to a clamp (13), and the spiral reactor (14) is fixed on the clamp (13). The ultrasonic generator (11) generates ultrasonic waves, which are transmitted through the metal frame (12) to the reaction solution inside the spiral reactor (14). The solution is located inside the spiral reactor (14), and the inlet of the spiral reactor (14) is connected to a mixer (2), while the outlet is connected to an alternating filter (5) through a pipeline.

4. The device for continuous operation of ultrasound-assisted oxalate precipitation according to claim 3, characterized in that: The spiral tube reactor (14) is wrapped with heating belts on both the inside and outside.

5. The device for continuous operation of ultrasound-assisted oxalate precipitation according to claim 3, characterized in that: The alternating filter (5) consists of two flat plate filters that are used alternately.

6. A method for continuous ultrasonic-assisted oxalate precipitation, using the apparatus as described in claim 5, characterized in that: Includes the following steps: S1: Prepare an oxalic acid solution as a precipitant; Prepare a nitrate solution as the stock solution; S2: Nitrate solution and oxalic acid solution are sent to mixer (2) by the original liquid pump (3) and the precipitant pump (4), respectively, and the two solutions are mixed in mixer (2); S3: The solution in the mixer (2) enters the reactor (1), and the slurry after the reaction is directly pumped to the alternating filter (5) and obtained oxalate solid material by vacuum filtration.

7. The method for continuous ultrasonic-assisted oxalate precipitation according to claim 6, characterized in that: In S2, the original liquid pump (3) and the precipitant pump (4) provide segmented flow solutions.

8. The method for continuous ultrasonic-assisted oxalate precipitation according to claim 6, characterized in that: In S2, the direction of liquid flow is changed by the baffle (7) in the mixer (2).

9. The method for continuous ultrasonic-assisted oxalate precipitation according to claim 6, characterized in that: In step S3, the remaining filtrate is sent to the mother liquor storage tank (6).

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