Method and system for preparing uniform nano-barium sulfate particles based on ultrasound

Abstract

The present application discloses a method and system for preparing uniform nano-barium sulfate particles based on ultrasound-assisted treatment, the method comprising: delivering equal volumes of sodium sulfate solution and barium chloride solution to a reaction vessel, adjusting the position and parameters of an ultrasonic transducer, and adjusting the power and frequency according to a preset curve; slowly transferring the slurry obtained by the reaction to a post-processing container, adding a sodium hexametaphosphate solution, and placing it in an ultrasonic cleaning device for dispersion treatment; using a continuous flow method to dispense the product into a cleaned sealed container, controlling the filling amount and sealing it for constant temperature storage. Through the scheme of the present application, nano-barium sulfate particles with small particle size and uniform distribution can be generated.

Description

Technical Field

[0001] The present application relates to the field of barium sulfate granulation, and in particular to a method and system for preparing uniform nano-barium sulfate particles based on ultrasound assistance. Background Art

[0002] Barium sulfate is an important inorganic functional material with good chemical stability, corrosion resistance and high temperature resistance, and is widely used in the industrial field. Traditional barium sulfate is limited in many high-end application fields due to its large particle size (usually at the micron level). With the development of nanotechnology, nano-level barium sulfate has gradually attracted attention due to its excellent performance. Nano-barium sulfate has the characteristics of large specific surface area, good dispersibility, and strong hiding power, and shows unique application value in the fields of plastics, rubber, coatings, papermaking, inks, etc. At present, the methods for preparing nano-barium sulfate mainly include chemical precipitation method, microemulsion method, sol-gel method, hydrothermal method, etc. Although the traditional chemical precipitation method has a simple process, the product particle size distribution is wide and the agglomeration phenomenon is serious; the microemulsion method can better control the particle size, but the cost is high and it is difficult to achieve industrial production; the sol-gel method has a complex process and strict reaction conditions; although the hydrothermal method can prepare nanoparticles with complete crystal form, it has high equipment requirements and high energy consumption. Therefore, it is of great practical significance to develop a simple, economical, environmentally friendly and controllable method for preparing nano-barium sulfate.

[0003] In recent years, researchers have conducted a lot of exploration and improvement on the preparation methods of nano-barium sulfate. Among them, the chemical precipitation method is widely used because of its simple process and low cost, but it is difficult to achieve precise control of particles and optimization of dispersion; the hydrothermal method can obtain particles with uniform crystal form and good dispersion, but due to the harsh reaction conditions and high energy consumption, its industrial production is limited; the microemulsion method uses the emulsion interface to limit particle growth and can prepare nano-barium sulfate with uniform particle size distribution, but it requires a large amount of surfactants and has a greater impact on the environment; and although the gas phase synthesis method has advantages in particle size control and purity, its equipment is complex and the production cost is high, which is difficult to meet the needs of large-scale applications.

[0004] Therefore, a technical solution is urgently needed to generate nano-barium sulfate particles with small particle size and uniform distribution. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the present application discloses a method and system for preparing uniform nano-barium sulfate particles based on ultrasound assistance. The present application solves the technical problems of the prior art such as the easy agglomeration of nano-particles.

[0006] The embodiment of the present application discloses a method for preparing uniform nano-barium sulfate particles based on ultrasound-assisted treatment, comprising: adding sodium sulfate solid to anhydrous ethanol in a batch-feeding manner and mechanically stirring the mixture until the solution is clear and transparent, thereby obtaining a sodium sulfate solution; adding barium chloride solid to anhydrous ethanol in a batch-feeding manner and stirring the mixture until the solution is uniform and transparent, thereby obtaining a barium chloride solution; delivering equal volumes of the sodium sulfate solution and the barium chloride solution to a reaction container, adjusting the position and parameters of an ultrasonic transducer, and adjusting the power and frequency according to a preset curve; slowly transferring the slurry obtained by the reaction to a post-processing container, adding a sodium hexametaphosphate solution, and placing the slurry in an ultrasonic cleaning device for dispersion treatment; and dispensing the product into a cleaned sealed container in a continuous flow manner, and sealing the container after controlling the filling amount for constant temperature storage.

[0007] In a possible implementation, solid sodium sulfate is added to anhydrous ethanol in batches and mechanically stirred until the solution is clear and transparent to obtain a sodium sulfate solution, comprising: adding anhydrous ethanol as a reaction medium into a target container; adding solid sodium sulfate to the reaction medium in batches and controlling the concentration of the sodium sulfate solution; mechanically stirring the reaction medium until the solution is clear and transparent; and sealing the sodium sulfate solution and adjusting it to a preset temperature.

[0008] In a possible implementation, solid barium chloride is added to anhydrous ethanol in batches and stirred until the solution is uniform and transparent to obtain a barium chloride solution, comprising: adding solid barium chloride to anhydrous ethanol in batches; stirring the barium chloride solution until the solution is uniform and transparent; and sealing the barium chloride solution and adjusting it to the same temperature as the sodium sulfate solution.

[0009] In a possible implementation, the sodium sulfate solution and the barium chloride solution are transported to the reaction container in equal volumes, the position and parameters of the ultrasonic transducer are adjusted, and the power and frequency are adjusted according to a preset curve, including: transporting the sodium sulfate solution and the barium chloride solution to the reaction container in equal volumes; immersing the ultrasonic transducer below the reaction liquid surface to a preset depth; setting an initial value of the ultrasonic frequency and outputting power using a pulse modulation method; controlling the temperature of the reaction system through a water bath to maintain a constant temperature of the reaction system; gradually increasing the power to a set value according to a preset curve; adjusting the transducer position using a three-dimensional spiral trajectory; and fine-tuning the sound field by changing the ultrasonic frequency.

[0010] In one possible implementation, the slurry obtained by the reaction is slowly transferred to a post-processing container, a sodium hexametaphosphate solution is added, and the mixture is placed in an ultrasonic cleaning device for dispersion treatment, including: slowly transferring the slurry obtained by the reaction to a post-processing container; slowly adding the sodium hexametaphosphate solution to the post-processing container; transferring the mixed solution to an ultrasonic cleaning device for dispersion treatment; controlling the dispersion treatment time and keeping the system temperature stable.

[0011] In a possible implementation, the product is packaged into cleaned sealed containers in a continuous flow manner, and the filling amount is controlled and then sealed for constant temperature storage, including: packaging the product into cleaned sealed containers in a continuous flow manner; controlling the filling amount of each sealed container; sealing all containers; and storing the sealed products in a constant temperature environment.

[0012] In a possible implementation, the step of gradually increasing the power to a set value according to a preset curve includes:

[0013] ,

[0014] in, represents the power output at time t, Indicates the rated power value of the device. Indicates the time since startup.

[0015] In a possible implementation, the sound field is fine-tuned by changing the ultrasonic frequency, including:

[0016] ,

[0017] in, Indicates the frequency value at time t, in kHz. Indicates the time after the set power is reached.

[0018] An embodiment of the present application also discloses an ultrasonic control system using the method described in any of the above embodiments, comprising: a position unit, a power unit and a frequency unit; wherein the position unit is used to immerse the ultrasonic transducer below the reaction liquid surface to a preset depth, and adjust the transducer position using a three-dimensional spiral trajectory; the power unit is used to output power using pulse modulation, and gradually increase the power to a set value according to a preset curve; the frequency unit is used to set the initial value of the ultrasonic frequency, and fine-tune the sound field by changing the ultrasonic frequency.

[0019] An embodiment of the present application also discloses an ultrasonic control device for assisting in the preparation of uniform nano-barium sulfate particles, comprising: a processor, a memory, and a system bus; wherein the processor and the memory are connected via the system bus; the memory is used to store one or more programs, wherein the one or more programs include instructions, and when the instructions are executed by the processor, the processor executes the method described in any one of the above embodiments.

[0020] Compared with the prior art, the embodiments of the present application achieve the following beneficial effects:

[0021] The present invention discloses a method and system for preparing uniform nano-barium sulfate particles based on ultrasound-assisted preparation. Through the ultrasound-assisted preparation process, nano-barium sulfate particles with small particle size and uniform distribution can be generated. The cavitation effect and mechanical effect of ultrasound can effectively break the particle agglomeration, promote the uniform nucleation and growth of particles, and thus prepare nano-particles with narrow particle size distribution. The present invention adopts anhydrous ethanol as the reaction medium, which is lower in cost and easy to realize industrial production compared with other methods such as microemulsion method and hydrothermal method. The present invention does not produce harmful waste during the preparation process, and the reaction medium anhydrous ethanol can be recycled and reused, which meets environmental protection requirements. In addition, the sodium hexametaphosphate used as a dispersant has little impact on the environment. By accurately controlling the position, power and frequency of the ultrasonic transducer, the present invention realizes the refined control of the reaction process, which not only improves the product quality, but also enhances the stability and repeatability of the process. The prepared nano-barium sulfate particles have the characteristics of large specific surface area, good dispersibility, strong covering power, etc., and show unique application value in the fields of plastics, rubber, coatings, papermaking, inks, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of a process for preparing uniform nano-barium sulfate particles based on ultrasound-assisted method disclosed in an embodiment of the present application;

[0024] Figure 2 A simulation schematic diagram of an ultrasonic transducer position control method disclosed in an embodiment of the present application;

[0025] Figure 3 A simulation schematic diagram of an ultrasonic frequency control method disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure unless otherwise specifically stated.

[0027] Those skilled in the art can understand that the terms "first", "second" and the like in the embodiments of the present disclosure are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor represent the necessary logical order between them. It should also be understood that in the embodiments of the present disclosure, "multiple" can refer to two or more, and "at least one" can refer to one, two or more. It should also be understood that for any component, data or structure mentioned in the embodiments of the present disclosure, in the absence of explicit limitation or contrary revelation given in the context, it can generally be understood as one or more. In addition, the term "and / or" in the present disclosure is only a description of the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present disclosure generally indicates that the associated objects before and after are an "or" relationship. It should also be understood that the description of each embodiment in the present disclosure emphasizes the differences between the embodiments, and the same or similar parts can refer to each other. For the sake of brevity, they will not be repeated one by one.

[0028] At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. The techniques, methods and devices known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered part of the specification. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] Figure 1 The present invention is a schematic flow chart of a method for preparing uniform nano-barium sulfate particles with the assistance of ultrasound, as disclosed in an embodiment of the present application.

[0031] like Figure 1 As shown, in step S101, sodium sulfate solid is added to anhydrous ethanol in batches and mechanically stirred until the solution is clear and transparent to obtain a sodium sulfate solution. The process includes: adding anhydrous ethanol as a reaction medium to a target container; adding sodium sulfate solid to the reaction medium in batches and controlling the concentration of the sodium sulfate solution; mechanically stirring the reaction medium until the solution is clear and transparent; and sealing the sodium sulfate solution and adjusting it to a preset temperature.

[0032] For the preparation of sodium sulfate solution, specifically, anhydrous ethanol can be selected as the reaction medium as the base solvent, and added to a container including but not limited to glass and other materials. At room temperature, a measured amount of sodium sulfate solid raw material is added to the container to control the final solution concentration to 0.25 mol / L. In order to ensure the accuracy of the solution preparation, the batch addition method is adopted: first add 50% of the total amount, and then add the remaining 50% after complete dissolution. During the addition process, mechanical stirring is continued, and the stirring rate is controlled within the range of 200-300 rpm. As the stirring proceeds, the solution gradually becomes clear and transparent. After the addition is completed, continue stirring for 10 minutes to ensure that the solute is fully dissolved. The prepared solution is sealed and stored, and the temperature is adjusted to 30°C. Maintain moderate stirring during the temperature adjustment process to ensure that the solution temperature is uniform. After the temperature stabilizes, the solution is left to stand for subsequent use. During the entire solution preparation process, attention should be paid to the sealing of the container to avoid changes in concentration caused by solvent volatilization.

[0033] In step S102, solid barium chloride is added to anhydrous ethanol in batches and stirred until the solution is uniform and transparent, so as to obtain a barium chloride solution. The process includes: adding solid barium chloride to anhydrous ethanol in batches; stirring the barium chloride solution until the solution is uniform and transparent; and sealing the barium chloride solution and adjusting it to the same temperature as the sodium sulfate solution.

[0034] For the preparation of barium chloride solution, specifically, the same solvent system as that for the preparation of sodium sulfate solution can be used, and anhydrous ethanol can be used as the reaction medium. Weigh the solid barium chloride raw material according to the calculated amount, and the target preparation concentration is also 0.25 mol / L. Add the weighed barium chloride solid to anhydrous ethanol in batches, and control the amount added each time to one-third of the total amount. Maintain continuous stirring during the addition process, and keep the stirring rate at 200-300 rpm. After observing that the solution gradually becomes uniform and transparent, continue stirring for 15 minutes to ensure that the barium chloride is completely dissolved. The prepared barium chloride solution is sealed and stored, and its temperature is also controlled to reach and maintain at 30°C. During the heating process, maintain a small amount of stirring to promote uniform temperature distribution. When the solution temperature stabilizes at the target temperature, let it stand for use.

[0035] In step S103, the sodium sulfate solution and the barium chloride solution are transported to the reaction container in equal volumes, the ultrasonic transducer position and parameters are adjusted, and the power and frequency are adjusted according to a preset curve. This includes: transporting the sodium sulfate solution and the barium chloride solution to the reaction container in equal volumes; immersing the ultrasonic transducer below the reaction liquid surface to a preset depth; setting the initial value of the ultrasonic frequency and outputting the power in a pulse modulation manner; controlling the temperature of the reaction system by a water bath to maintain a constant temperature of the reaction system; gradually increasing the power to a set value according to a preset curve; adjusting the transducer position using a three-dimensional spiral trajectory; and fine-tuning the sound field by changing the ultrasonic frequency.

[0036] Further, the step of gradually increasing the power to a set value according to a preset curve includes:

[0037] ,

[0038] in, represents the power output at time t, Indicates the rated power value of the device. Indicates the time since startup.

[0039] Further, the sound field is fine-tuned by changing the ultrasonic frequency, including:

[0040] ,

[0041] in, Indicates the frequency value at time t, in kHz. Indicates the time after the set power is reached.

[0042] In one implementation scenario, for the construction of the reaction system, the sodium sulfate solution and barium chloride solution prepared and temperature-adjusted in advance can be delivered to the reaction vessel by equal volume simultaneous feeding by equal volume injection. During the delivery process, the flow rates of the two solutions are controlled to be consistent to ensure the uniformity of the mixing process. After the solution delivery is completed, the temperature of the reaction system needs to be stably controlled at 30°C. Before starting the ultrasonic generator, the system is first pretreated. Preferably, the immersion depth of the ultrasonic transducer can be adjusted to 23.7 mm below the reaction liquid surface, which can be achieved by adjusting the height of the bracket. The initial value of the ultrasonic frequency is set to 28.5 kHz, which is obtained by analyzing the acoustic characteristics of the reaction system. The output of ultrasonic power adopts pulse modulation, and the pulse period is set to 2.83 seconds, of which the pulse action time is 1.98 seconds and the interval time is 0.85 seconds. The reaction vessel is placed in a water bath, and the water bath temperature is set to 28.6-29.2°C, slightly lower than the reaction temperature, to offset the heat generated by ultrasonic energy conversion.

[0043] After starting the ultrasonic system, a progressive power control scheme was adopted: first, the power was set to 17.3% of the rated power and maintained for 183 seconds to allow the reaction system to gradually adapt to the ultrasonic field environment; then the power was gradually increased according to the preset curve, and the power increase curve used the following equation:

[0044] ,

[0045] in is the rated power value of the device, and t is the time after startup (seconds). When the power reaches 40% of the rated power, the output state is maintained.

[0046] During the reaction process, the sound field intensity distribution is dynamically optimized by adjusting the transducer position. The transducer position is adjusted using a three-dimensional spiral trajectory, and the specific trajectory equation is:

[0047] ,

[0048] Where r is the starting radius of 8.3 mm, h is the total displacement height of 4.7 mm, and θ is the rotation angle, which varies between 0 and 75.4 degrees, with the position adjusted every 25.1 degrees. The adjustment process lasts for 437 seconds, after which the transducer remains in the final position.

[0049] To ensure the uniformity of the sound field, the sound field is fine-tuned after the power reaches the set value. The sound field is adjusted by changing the ultrasonic frequency. The frequency adjustment range is between 28.5±0.73 kHz, and the adjustment step is 0.12 kHz. The frequency adjustment follows the following rules:

[0050] ,

[0051] Where t is the time (in seconds) after the set power is reached. This adjustment lasts for 317 seconds, after which the frequency is fixed at the optimal value. That is, after 317 seconds of adjustment, the frequency is finally fixed at 28.6166 kHz. This frequency is slightly higher than the initial frequency of 28.5 kHz, an increase of about 0.12 kHz. This minor adjustment is to obtain better sound field uniformity after long-term operation.

[0052] After the above adjustment, the reaction system was subjected to ultrasonic treatment for 15 minutes under this condition. During this period, the water bath temperature was kept stable at 29.2°C, and the reaction system temperature was maintained constant at 30°C by controlling the water bath circulation flow rate at 2.37 L / min. If the temperature fluctuation exceeded ±0.3°C, the water bath temperature was adjusted to compensate. The compensation temperature change value ΔT was calculated as: ΔT = -0.83ΔTr, where ΔTr is the deviation of the reaction system temperature from the set value.

[0053] In step S104, the slurry obtained by the reaction is slowly transferred to a post-processing container, a sodium hexametaphosphate solution is added, and the slurry is placed in an ultrasonic cleaning device for dispersion treatment. The steps include: slowly transferring the slurry obtained by the reaction to a post-processing container; slowly adding the sodium hexametaphosphate solution to the post-processing container; transferring the mixed solution to an ultrasonic cleaning device for dispersion treatment; controlling the dispersion treatment time and keeping the system temperature stable.

[0054] For product post-treatment, in one embodiment, after the reaction is completed, the slurry obtained by the reaction is transferred to a post-treatment container. During the transfer process, a slow pouring method is adopted to avoid violent shaking and causing particle agglomeration. A sodium hexametaphosphate solution with a concentration of 4g / L is slowly added to the post-treatment container, and the addition rate is controlled so that its final concentration is diluted to 0.3g / L. After the addition is completed, the mixed solution is transferred to an ultrasonic cleaning device for ultrasonic dispersion treatment. The dispersion treatment time is set to 15 minutes, and the system temperature is kept stable during this process. Through ultrasonic dispersion treatment, the nanoparticles in the system are fully dispersed to form a stable suspension. The product after the treatment is completed is the required nano barium sulfate particle dispersion liquid. In the whole post-treatment process, it is necessary to pay attention to the continuity of the operation of each step to avoid particle agglomeration due to the long residence time in the middle.

[0055] In step S105, the product is divided into cleaned sealed containers in a continuous flow manner, and the filling amount is controlled and then sealed for constant temperature storage. This includes: dividing the product into cleaned sealed containers in a continuous flow manner; controlling the filling amount of each sealed container; sealing all containers; and storing the sealed products in a constant temperature environment.

[0056] For product storage, the post-processed product can be packaged into multiple sealed containers. The packaging process adopts a continuous flow method to prevent product sedimentation during the packaging process. The sealed containers are cleaned in advance to ensure that the inner wall is free of impurities. When packaging, control the filling amount of each container to about 80% of the container volume, leaving appropriate space to prevent volume expansion caused by temperature changes. After packaging, all containers are sealed to ensure that the seals are intact. Store the sealed products in a constant temperature environment away from direct sunlight and drastic temperature fluctuations.

[0057] Figure 2 This is a schematic diagram of an ultrasonic transducer position control method disclosed in an embodiment of the present application. This figure uses a dual-view method to show the ultrasonic transducer position adjustment method and its corresponding sound field distribution effect. The left side is a top view and the right side is a side view. Through this combined display method, you can fully understand the motion trajectory of the transducer in three-dimensional space and the sound field characteristics it generates.

[0058] The motion trajectory of the transducer is described by three parametric equations: x(θ) = r·cos(θ)·(1 - θ / 75.4), y(θ) = r·sin(θ)·(1 - θ / 75.4), z(θ) = h·θ / 75.4. The figure shows five typical trajectories under different parameter combinations, including r values ​​of 12.5mm, 10.1mm, 8.3mm (optimal value), 6.5mm and 4.7mm, and the corresponding h values ​​of 5.9mm, 5.3mm, 4.7mm (optimal value), 4.1mm and 3.5mm.

[0059] From the top view, it can be observed that as the r value decreases, the plane projection trajectory of the transducer gradually shrinks toward the center. When r=12.5mm, the trajectory is too divergent, resulting in insufficient sound field intensity in the edge area; and when r=4.7mm, the trajectory is too concentrated, resulting in excessive concentration of sound energy in the center area. When the optimal value r=8.3mm, the spatial distribution of the trajectory achieves the best balance of sound field coverage.

[0060] The side view shows the vertical motion characteristics of the transducer corresponding to different h values. When h=5.9mm, the transducer rises too much, causing the sound field intensity in the upper area to be significantly weakened; when h=3.5mm, the transducer rises insufficiently, causing the sound field distribution to be too concentrated in the lower area. The optimal value h=4.7mm combined with an angle interval of 25.1 degrees enables the transducer to achieve the most uniform sound field spatial distribution during the 437-second adjustment process.

[0061] The sound field distribution effect is represented by the blue (top view) and red (side view) gradient areas. From the top view, it can be seen that the sound field intensity shows a gradual attenuation characteristic from the transducer position outward, which is consistent with the attenuation law of ultrasound in liquid. The sound field distribution in the side view shows the propagation characteristics of sound energy in the vertical direction. As the transducer position increases, the sound field intensity gradually decreases but the coverage range expands.

[0062] The initial position of the transducer is set at 23.7 mm below the liquid surface. This depth is chosen based on the following considerations: first, it is necessary to ensure that the transducer is fully immersed to avoid sound wave scattering; second, this depth can ensure the efficiency of sound wave propagation while avoiding local overheating caused by the transducer being too close.

[0063] During the trajectory optimization process, it was found that when the optimal parameter combination (r=8.3mm, h=4.7mm) was used, the transducer adjusted its position every 25.1 degrees. This discrete control method can not only ensure the accuracy of the adjustment, but also avoid the mechanical vibration caused by continuous movement. The entire adjustment process was completed within 437 seconds. This time setting took into account the dynamic characteristics of the reaction system and the requirements for the stability of the sound field.

[0064] The control of sound field uniformity is achieved through two levels: the coordination of spatial position adjustment and frequency adjustment. After the transducer moves to the final position, the system fine-tunes the sound field distribution by adjusting the frequency within the range of 28.5±0.73kHz. The frequency adjustment follows the law of f(t) = 28.5 + 0.73sin(0.0082t)·e^(-0.0037t), and finally stabilizes at 28.6166kHz after 317 seconds of adjustment. The selection of this frequency value is based on the sound field uniformity test results.

[0065] Experimental data show that when the transducer moves along the optimal trajectory, the difference in sound field intensity between any two points in the reaction system does not exceed 8%. This highly uniform sound field distribution provides the necessary conditions for uniform nucleation and growth of nanoparticles. Through the coordination of position adjustment and frequency adjustment, not only the spatial uniformity of the sound field is ensured, but also the local excessive sonochemical effect is effectively suppressed, which guarantees the stability of product quality.

[0066] Figure 3 This is a schematic diagram of an ultrasonic frequency control method disclosed in an embodiment of the present application. The acoustic wave frequency adjustment simulation diagram shows the precise frequency change process within a 317-second adjustment cycle. The diagram uses time as the horizontal axis (unit: seconds) and frequency as the vertical axis (unit: kHz), and uses a multi-dimensional curve system to show the dynamic characteristics, stability analysis, and system response characteristics of frequency regulation.

[0067] From the perspective of longitudinal frequency distribution, the adjustment range of the system is limited to 28.5±0.73kHz. Among them, 28.5kHz is used as the initial frequency, and this value is selected based on the analysis results of the acoustic characteristics of the reaction system. The blue solid line in the figure represents the optimal frequency adjustment curve, and its mathematical expression is f(t) = 28.5 + 0.73sin(0.0082t)·e^(-0.0037t). This expression contains a combination of sinusoidal terms and exponential attenuation terms, where 0.0082 is the angular frequency coefficient and 0.0037 is the attenuation coefficient. The selection of these two parameters is based on the analysis results of the dynamic response characteristics of the system.

[0068] The distribution of key nodes on the timeline shows three characteristic stages of the adjustment process: the first stage (0-79.25 seconds, point P1) is a rapid response period, with the frequency fluctuating between 28.5-29.23kHz. This stage is mainly used for system initialization adaptation; the second stage (79.25-237.75 seconds, points P2 to P3) is a transition adjustment period, with the frequency change gradually converging and the fluctuation amplitude significantly reduced; the third stage (237.75-317 seconds) is a fine adjustment period, with the frequency finally stabilized at 28.6166kHz.

[0069] The gain response curve (orange dashed line) and phase response curve (green dashed line) in the figure reflect the dynamic characteristics of the system during the frequency adjustment process. The gain response curve shows that the system gain is large in the initial stage, which is conducive to quickly establishing the sound field; then the gain gradually decreases and the system enters a stable working state. The phase response curve shows that the system maintains good phase continuity throughout the adjustment process, avoiding sound field disturbances caused by phase mutations.

[0070] The stability analysis area (rectangular box on the right in the figure) shows the frequency stability characteristics of the system in the final stage. The actual frequency fluctuation is limited to ±0.12kHz, and this level of accuracy meets the requirements of sound field uniformity. The fluctuation indicator (red line segment) in the figure intuitively shows the frequency deviation in actual operation, and its amplitude is much smaller than the theoretical allowable range, which confirms the reliability of the control scheme.

[0071] The envelope of the system (dashed blue line) defines the boundaries of the frequency change. The upper envelope follows the limit of 28.5 + 0.73kHz, and the lower envelope follows the limit of 28.5 - 0.73kHz. The actual adjustment curve always remains between these two envelopes. This constraint ensures the controllability of the frequency adjustment process. The adjustment step size is set to 0.12kHz. The choice of this step size value comprehensively considers the balance between system response speed and control accuracy.

[0072] Comparative analysis shows that the frequency adjustment scheme has the following advantages: First, the combination of sinusoidal modulation and exponential decay ensures both the flexibility of the initial adjustment and the stability of the later adjustment; second, the 317-second adjustment period matches the 437-second transducer position adjustment, achieving coordinated optimization on the time scale; third, the final frequency stabilizes at 28.6166 kHz, which is about 0.12 kHz higher than the initial value. This slight frequency adjustment effectively compensates for the changes in the medium properties during the reaction process.

[0073] From the perspective of the regulation mechanism, the frequency regulation process is directly related to the sound field distribution. The large frequency change in the early stage helps to break the unevenness of the local sound field distribution. As the reaction proceeds, the frequency regulation amplitude gradually decreases, and the sound field distribution tends to be stable. The fine adjustment in the final stage is used to maintain the uniformity of the sound field and ensure the continuous and stable reaction. This dynamic regulation strategy fully considers the propagation characteristics of ultrasound in the reaction medium and realizes the precise control of the sound field distribution.

[0074] Furthermore, an embodiment of the present application discloses an ultrasonic control system that applies the method described in any of the above embodiments, including: a position unit, a power unit and a frequency unit; wherein the position unit is used to immerse the ultrasonic transducer below the reaction liquid surface to a preset depth, and adjust the transducer position using a three-dimensional spiral trajectory; the power unit is used to output power using pulse modulation, and gradually increase the power to a set value according to a preset curve; the frequency unit is used to set the initial value of the ultrasonic frequency, and fine-tune the sound field by changing the ultrasonic frequency.

[0075] Furthermore, an embodiment of the present application also discloses an ultrasonic control device for assisting in the preparation of uniform nano-barium sulfate particles, comprising: a processor, a memory, and a system bus; the processor and the memory are connected via the system bus; the memory is used to store one or more programs, the one or more programs comprising instructions, which, when executed by the processor, enable the processor to execute any of the above methods.

[0076] Furthermore, an embodiment of the present application also discloses a computer program product, which, when executed on a terminal device, enables the terminal device to execute any of the above methods.

[0077] It can be known from the description of the above implementation mode that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., including several instructions for enabling a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0078] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0079] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0080] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing uniform nano-barium sulfate particles based on ultrasound, characterized in that: include: Solid sodium sulfate is added to anhydrous ethanol in batches and mechanically stirred until the solution is clear and transparent to obtain a sodium sulfate solution; Adding solid barium chloride into anhydrous ethanol in batches and stirring until the solution is uniform and transparent to obtain a barium chloride solution; The sodium sulfate solution and the barium chloride solution are transported in equal volumes into a reaction container, the position and parameters of the ultrasonic transducer are adjusted, and the power and frequency are adjusted according to a preset curve, including: delivering the sodium sulfate solution and the barium chloride solution to a reaction vessel in equal volumes; Immerse the ultrasonic transducer below the reaction liquid surface to a preset depth; Set the initial value of ultrasonic frequency and use pulse modulation to output power; The temperature of the reaction system is controlled by a water bath to maintain a constant temperature of the reaction system; Gradually increase the power to the set value according to the preset curve; The transducer position is adjusted using a three-dimensional spiral trajectory; Fine-tune the sound field by changing the ultrasonic frequency, including: ， in, Indicates the frequency value at time t, in kHz. Indicates the time after reaching the set power, the unit of t is seconds; The slurry obtained by the reaction is slowly transferred to a post-treatment container, a sodium hexametaphosphate solution is added, and the slurry is placed in an ultrasonic cleaning device for dispersion treatment; The product is packaged into cleaned sealed containers in a continuous flow manner, and the containers are sealed after the filling volume is controlled for constant temperature storage.

2. The method according to claim 1, characterized in that in, Solid sodium sulfate is added to anhydrous ethanol in batches and mechanically stirred until the solution is clear and transparent to obtain a sodium sulfate solution, comprising: adding anhydrous ethanol as a reaction medium into the target container; adding solid sodium sulfate to the reaction medium in batches, and controlling the concentration of the sodium sulfate solution; Mechanically stirring the reaction medium until the solution is clear and transparent; The sodium sulfate solution is sealed and adjusted to a preset temperature.

3. The method according to claim 1, characterized in that: in, The solid barium chloride is added to the anhydrous ethanol by adding in batches and stirred until the solution is uniform and transparent to obtain a barium chloride solution, comprising: Add solid barium chloride to anhydrous ethanol in portions; Stirring the barium chloride solution until the solution is uniform and transparent; The barium chloride solution was sealed and adjusted to the same temperature as the sodium sulfate solution.

4. The method according to claim 1, characterized in that: in, The slurry obtained by the reaction is slowly transferred to a post-processing container, a sodium hexametaphosphate solution is added, and the slurry is placed in an ultrasonic cleaning device for dispersion treatment, including: Slowly transfer the slurry obtained from the reaction to a post-processing container; Slowly adding the sodium hexametaphosphate solution into the post-processing container; The mixed solution is transferred to an ultrasonic cleaning device for dispersion treatment; Control the dispersion processing time and keep the system temperature stable.

5. The method according to claim 1, characterized in that in, The product is dispensed into cleaned sealed containers in a continuous flow manner, and the filling volume is controlled and sealed for constant temperature storage, including: The product is dispensed into cleaned sealed containers in a continuous flow manner; Control the filling quantity of each sealed container; Seal all containers; Store the sealed product in a constant temperature environment.

6. The method according to claim 1, characterized in that in, Gradually increase the power to the set value according to the preset curve, including: ， in, represents the power output at time t, Indicates the rated power value of the device. Indicates the time after startup, the unit of t is seconds.

7. An ultrasonic control device for assisting the preparation of uniform nano-barium sulfate particles, characterized in that: include: A processor, a memory, and a system bus; wherein the processor and the memory are connected via the system bus; The memory is used to store one or more programs, wherein the one or more programs include instructions, and when the instructions are executed by the processor, the processor executes the method according to any one of claims 1 to 6.

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