A method for selectively salt precipitation of brine based on pH and temperature coordination pulse oscillation

Abstract

The present application belongs to the field of brine chemical industry and crystallization separation technology, and particularly relates to a brine selective salt precipitation method based on pH and temperature coordination pulse oscillation. The characteristic response time of different salts is determined through step disturbance experiment, and an asymmetric periodic pulse waveform meeting the selective condition is designed accordingly. A controller generates pH pulse and temperature pulse in real time according to a segmented function, so that the target salt is preferentially nucleated and grown, and the impurity salt is passively inhibited by kinetics due to response lag. The pulse response intensity and the selectivity factor are calculated, and the pulse parameters are optimized according to the adaptive law, and the impurity co-precipitation is prewarned through the second derivative of conductivity. The present application does not need static solubility data, can adapt to the fluctuation of brine composition, can calculate the selectivity factor in real time through the double-frequency pulse method, can automatically adjust the pulse amplitude and period by using the gradient descent adaptive law, can prewarn the impurity co-precipitation by using the second derivative of conductivity, can ensure that the system always works in the optimal selective interval, can realize high-selectivity separation, and can improve the product purity.

Description

Technical Field

[0001] This invention belongs to the field of brine chemical engineering and crystallization separation technology, and particularly relates to a selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation. Background Technology

[0002] Brine is a complex aqueous solution containing various inorganic salts, widely found in salt lakes, underground brine, concentrated seawater desalination brine, and industrial saline wastewater. The efficient separation and extraction of target salts from brine is a core process in fields such as salt chemical industry, lithium extraction from salt lakes, and resource utilization of seawater desalination.

[0003] Traditional salt precipitation methods mainly rely on techniques such as multi-effect evaporation, vacuum evaporation, or cooling crystallization. By controlling temperature and concentration, the solution is brought to a supersaturated state, causing the target salt to crystallize out. However, simply controlling temperature and concentration is insufficient to ensure the target salt precipitates preferentially while impurities precipitate in brine containing multiple salts, often resulting in co-crystallization of the target salt and impurities, leading to low product purity. Adjusting the pH of the brine by adding strong acids or bases such as hydrochloric acid, sulfuric acid, sodium hydroxide, and potassium hydroxide can cause secondary pollution. Summary of the Invention

[0004] This invention addresses the technical problems existing in brine chemical processing and crystallization separation by proposing a rationally designed, simple, and theoretically sound method for selective brine salt precipitation based on pH and temperature-coordinated pulse oscillation.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation, characterized by comprising the following steps:

[0006] S1. Apply a short-time step perturbation to the brine and calculate the characteristic response time of the dominant salts in the brine. ;

[0007] S2. Based on the difference between the target salt and the impurity salt, design a periodic asymmetric pulse waveform with parameters that satisfy the selectivity condition.

[0008] S3. During the salt precipitation process, the controller automatically generates a continuous pulse waveform according to a preset cycle and calculates the target value in real time using a piecewise function. , The actual value is tracked by the target waveform using PID closed-loop control, so that the target salt is preferentially nucleated on each pulse rising edge, while the impurity salt is suppressed due to the response lag.

[0009] S4. Monitor the conductivity response after the pulse in real time and calculate the pulse response intensity. The selectivity factor was calculated by alternately applying high-frequency and low-frequency pulses. and the target selectivity factor Compare;

[0010] S5. Adjust the pulse amplitude according to the adaptive law. and pulse period ,make Simultaneously monitor the second derivative of conductivity. Early warning of impurity nucleation;

[0011] S6. Once the cumulative crystallization amount of the target salt reaches the target, solid-liquid separation is performed to obtain high-purity crystals.

[0012] Preferably, the characteristic response time of the dominant salt The calculation formula is:

[0013] ,

[0014] in, For characteristic response time, Real-time conductivity For steady-state conductivity, This represents the change in peak conductivity. The characteristic response time of the salt to be identified, This is the time elapsed from the moment of the disturbance to the present moment.

[0015] Preferably, the selectivity condition satisfied by the S2 parameter is:

[0016] ,

[0017] in, The characteristic response time of the target salt. The pulse rise time, The pulse hold time, This represents the characteristic response time of the impurity salt.

[0018] Preferably, in S3 The calculation formula is:

[0019] ,

[0020] in, For a moment The target pH value, Baseline pH value This is the start time of the current pulse cycle. The duration of the pH decrease, The duration of the pH rise. For pH to remain stable, For pulse period, The pulse amplitude. The rising edge shape index, The falling edge shape index.

[0021] Preferably, in S3 The calculation formula is:

[0022] ,

[0023] in, For a moment Target temperature Baseline temperature The amplitude of the temperature pulse. For a moment The target pH value, This is the start time of the current pulse cycle. The duration of the temperature drop. The duration of the temperature rise. For the time it takes for the temperature to remain stable, For pulse period, The coupling coefficient between pH and temperature during the heating phase. The coupling coefficient between pH and temperature during the cooling phase. To cool along the shape index, To increase the temperature along the shape index, This refers to the duration of the slow heating process.

[0024] Preferably, the impulse response intensity in S4 The calculation formula is:

[0025] ,

[0026] in, The impulse response intensity, The conductivity at the start of the pulse. For real-time conductivity, For fractional order, The attenuation coefficient is... For continuous response time, The characteristic response time of the target salt is determined by calculating the selectivity factor through alternating application of high-frequency and low-frequency pulses. The calculation formula is:

[0027] ,

[0028] in, As a selectivity factor, The angular frequency under high-frequency pulses, The angular frequency under low-frequency pulses, For system transfer function, The phase sensitivity coefficient, This represents the phase lag difference between high and low frequencies. As a reference phase difference, The average characteristic response time, For the pulse to change steeply along its duration, The pulse hold time, This is the matching ratio index.

[0029] Preferably, in step S5, the pulse amplitude is adjusted according to the adaptive law. The calculation formula is:

[0030] ,

[0031] in, The updated pulse amplitude, For the first Pulse amplitude during the next adjustment For target selectivity factor, For the first The target selectivity factor was measured after the second pulse ended. The gain coefficient is used to adjust the pulse period according to the adaptive law. The calculation formula is:

[0032] ,

[0033] in, For the updated pulse period, the first The pulse period during each adjustment. This is the gain coefficient.

[0034] Preferably, the conditions for impurity nucleation early warning in S5 are as follows:

[0035] ,

[0036] in, The second derivative of conductivity. , The standard deviation of the second derivative when there are no impurities is given. Reduce the amplitude or extend the smoothing segment.

[0037] Preferably, the pH pulse is delivered by introducing... or remove The temperature pulse is achieved through heating or cooling.

[0038] Preferably, the brine is natural salt lake brine, underground brine, seawater desalination concentrated brine, or industrial saline wastewater; the target salt is one or more of sodium chloride, potassium chloride, lithium carbonate, magnesium sulfate, and borate.

[0039] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0040] 1. Based on the different response rates of different salts to pH and temperature disturbances, an asymmetric pulse waveform is designed to enable the target salt to nucleate rapidly along steep changes; impurity salts are kinetically suppressed due to hysteresis, thereby improving purity.

[0041] 2. The selectivity factor is calculated in real time using the dual-frequency pulse method, and the pulse amplitude and period are automatically adjusted using the gradient descent adaptive law. At the same time, the second derivative of conductivity is used to warn of impurity co-precipitation, ensuring that the system always operates in the optimal selectivity range.

[0042] 3. Adopt Achieving pH pulses eliminates the need for expensive acid and alkali resistant special equipment, thus reducing costs.

[0043] 4. Adopt As a pH pulse medium and temperature pulse medium, it does not add any chemicals throughout the process, has no secondary pollution, and also has the additional environmental benefits of carbon capture and utilization.

[0044] 5. The crystallization kinetic response time of salts can be determined through short-time step perturbation experiments without the need for static equilibrium data, making it suitable for brine systems with unknown composition or frequent fluctuations. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of a selective brine salt precipitation method based on pH and temperature-coordinated pulse oscillation. Detailed Implementation

[0047] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0048] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways than those described herein, and therefore the invention is not limited to the specific embodiments disclosed in the following specification.

[0049] In this embodiment, a coordinated pH and temperature pulse oscillation is employed to overcome the limitations of single-dimensional control in processing complex brine. Using pH pulses alone is almost ineffective for temperature-sensitive salts, while using temperature pulses alone fails to effectively suppress pH-sensitive impurities. This invention combines both, applying rapidly changing pH and temperature in stages or simultaneously. This allows the target salt to respond quickly and preferentially nucleate in one dimension, while impurity salts respond lag and are kinetically suppressed in the other dimension. This solves the selective separation problem in multi-salt systems and improves product purity. The dual-dimensional coordination provides control redundancy; even if one sensor drifts, the other dimension can still maintain a certain selectivity, enhancing system robustness. Furthermore, multi-level pulse sequences can be designed to achieve tiered separation, significantly improving the overall benefits of brine resource utilization.

[0050] A short-time step perturbation is applied to the brine, and the characteristic response times of the dominant salts in the brine are calculated. This invention quantitatively characterizes the crystallization kinetics response rates of different salts to pH or temperature changes without relying on static solubility data. Traditional methods require pre-determining complex thermodynamic models, but these are difficult to adapt to the large fluctuations in brine composition. This invention directly obtains the response times of each salt through rapid perturbation experiments, solving the problems of not being able to identify salt kinetic differences online and providing quantitative basis for pulse design. The operation is simple; the measured characteristic response times can be directly used for the selectivity conditions in step S2, ensuring that the pulse parameters accurately match the current brine kinetic characteristics, laying a reliable foundation for subsequent high-selectivity separation. Characteristic response times of dominant salts. The calculation formula is:

[0051] ,

[0052] in, For characteristic response time, Real-time conductivity For steady-state conductivity, This represents the change in peak conductivity. The characteristic response time of the salt to be identified, This is the time elapsed from the moment of the disturbance to the present moment.

[0053] Based on the difference between the target salt and the impurity salt, a periodic asymmetric pulse waveform is designed, whose parameters satisfy the selectivity condition; the selectivity condition satisfied by the parameters is:

[0054] ,

[0055] in, The characteristic response time of the target salt. The pulse rise time, The pulse hold time, The characteristic response time of the impurity salt is given. Different salts exhibit orders of magnitude differences in their response rates to pH or temperature disturbances, and pulse waveforms can translate this dynamic difference into macroscopic selective crystallization. Traditional methods, relying solely on steady-state control, cannot utilize these kinetic differences, resulting in poor selectivity and parameter dependence on experience. This invention sets a selectivity condition, strictly limiting the effective pulse duration to between the target salt's response time and the impurity salt's response time: the target salt can rapidly nucleate and grow within this time window, while the impurity salt is kinetically inhibited due to insufficient time, never reaching the critical supersaturation. This condition solves the technical problems of lacking quantitative basis for pulse parameter design and the unavoidable co-exudation of impurities in multi-salt systems.

[0056] During the salt precipitation process, the controller automatically generates continuous pulse waveforms according to a preset cycle and calculates the target value in real time using a piecewise function. , The actual value is tracked by the target waveform using PID closed-loop control, so that the target salt is preferentially nucleated on each pulse rising edge, while the impurity salt is suppressed due to the response lag. The calculation formula is:

[0057] ,

[0058] in, For a moment The target pH value, Baseline pH value This is the start time of the current pulse cycle. The duration of the pH decrease, The duration of the pH rise. For pH to remain stable, For pulse period, The pulse amplitude. The rising edge shape index, The falling edge shape index. The calculation formula is:

[0059] ,

[0060] in, For a moment Target temperature Baseline temperature The amplitude of the temperature pulse. For a moment The target pH value, This is the start time of the current pulse cycle. The duration of the temperature drop. The duration of the temperature rise. For the time it takes for the temperature to remain stable, For pulse period, The coupling coefficient between pH and temperature during the heating phase. The coupling coefficient between pH and temperature during the cooling phase. To cool along the shape index, To increase the temperature along the shape index, This refers to the duration of the slow heating process.

[0061] This step is crucial in translating the previously designed selective conditions into an engineering-executable operation. Traditional salt precipitation methods use constant pH or temperature control, which cannot actively create periodic oscillations of supersaturation, thus failing to utilize the differences in salt response rates. This invention uses piecewise functions to precisely describe the steep rising edge, hold segment, and gentle falling edge of the pulse, and utilizes the high dynamic response capability of PID to ensure that the actual value strictly tracks the waveform, thereby enabling the brine to reproduce asymmetric excitation in each cycle. The target salt reaches critical supersaturation instantaneously at the steep edge of each pulse and preferentially nucleates, while impurity salts, due to response lag, cannot nucleate in the gentle segment, thus transforming the kinetic difference into macroscopic selective crystallization. The controller provides a clear time-varying setpoint trajectory, avoiding open-loop trial and error; the PID closed-loop suppresses disturbances, ensuring waveform repeatability; and reducing equipment costs. This step ensures the dynamic realization of selective conditions, providing a stable process foundation for subsequent adaptive optimization. The baseline pH is the start and end point of the pulse cycle, representing the acid-base environment of the brine without pulse disturbances. Typically, a pH range is selected where the target salt can exist stably and impurities do not precipitate. Without a baseline, the amplitude and range of the pulse cannot be defined. The amplitude determines the drastic change in pH, directly affecting the peak value of supersaturation. If the amplitude is too small, the target salt cannot reach the critical supersaturation; if the amplitude is too large, it may lead to co-exudation of impurities or equipment corrosion. The length of the rising edge determines how quickly the supersaturation reaches its peak value. The pulse hold time provides a stable peak supersaturation, allowing the nucleated target crystals to continue growing. Without a hold period, the pulse is merely a spike, resulting in limited crystallization. An excessively long hold time reduces efficiency and may induce impurity nucleation; an excessively short hold time results in insufficient growth of the target salt. The length of the falling edge determines the rate at which the supersaturation falls back. By adjusting the falling slope, the degree to which impurities are kinetically suppressed can be controlled. The pulse period determines the frequency of pulse repetition. An excessively long period results in fewer pulses per unit time and lower overall crystallization efficiency; an excessively short period means the supersaturation of the previous pulse has not fully recovered, leading to baseline drift.

[0062] Adjust pulse amplitude according to adaptive law and pulse period ,make Simultaneously monitor the second derivative of conductivity. Early warning of impurity nucleation; impulse response intensity The calculation formula is:

[0063] ,

[0064] in, The impulse response intensity, The conductivity at the start of the pulse. For real-time conductivity, For fractional order, The attenuation coefficient is... For continuous response time, The characteristic response time of the target salt is determined by calculating the selectivity factor through alternating application of high-frequency and low-frequency pulses. The calculation formula is:

[0065] ,

[0066] in, As a selectivity factor, The angular frequency under high-frequency pulses, The angular frequency under low-frequency pulses, For system transfer function, The phase sensitivity coefficient, This represents the phase lag difference between high and low frequencies. As a reference phase difference, The average characteristic response time, For the pulse to change steeply along its duration, The pulse hold time, The selectivity factor is calculated using multiple elements, including amplitude ratio, phase difference, and response time matching ratio, to comprehensively evaluate the selectivity of the pulse for the target salt and impurity salts from three dimensions: frequency domain, time domain, and energy, overcoming the limitations of the traditional single amplitude ratio method. The amplitude ratio reflects the difference in system response intensity to high-frequency and low-frequency excitations. Fast-response salts are sensitive to high-frequency pulses and contribute significantly to the amplitude ratio; slow-response salts are insensitive to high frequencies and lower the amplitude ratio. This is a fundamental component of the selectivity factor; without the amplitude ratio, the relative contributions of fast and slow-response salts cannot be distinguished. Phase information is more sensitive than amplitude to the early appearance of impurities. When impurities begin to co-precipitate, the system's phase characteristics undergo slight changes, while the amplitude may not yet have changed significantly. By comparing the actual phase difference with the theoretical phase difference of the target salt, a decrease in selectivity can be detected in advance. The effective action time of the pulse must match the average response time of the salts in the brine. If the effective action time is much shorter than the average response time, the pulse is insufficient for the target salt to fully nucleate; if it is much longer than the average response time, impurities may also have a chance to respond. This factor penalizes mismatches and guides parameter optimization. By selecting two different frequencies of excitation, fast-response and slow-response salts can be excited respectively. High frequency is sensitive to fast salts, while low frequency responds to all salts. By comparing the system behavior at the two frequencies, selectivity information can be extracted.

[0067] Traditional methods use fixed parameters. When the brine composition changes, the original pulse may no longer meet the selectivity conditions, leading to the co-precipitation of impurities. This invention calculates the selectivity factor online. When the contribution of the target salt decreases and impurity salts begin to interfere, the pulse amplitude is increased using the gradient descent adaptive law to enhance the excitation of the target salt, while the period is adjusted to optimize the response efficiency. Furthermore, the second derivative of conductivity is extremely sensitive to the inflection point of the curve; when… When this occurs, it indicates an abnormal inflection point in conductivity decay, and the system immediately reduces the amplitude or extends the plateau phase to avoid impurity contamination. This mechanism solves the problems of fixed parameters failing to track system drift and the lack of early warning for impurity nucleation.

[0068] Adjust pulse amplitude according to adaptive law and pulse period ,make Adjust the pulse amplitude according to the adaptive law The calculation formula is:

[0069] ,

[0070] in, The updated pulse amplitude, For the first Pulse amplitude during the next adjustment For target selectivity factor, This is the current measured target selectivity factor. The gain coefficient is used to adjust the pulse period according to the adaptive law. The calculation formula is:

[0071] ,

[0072] in, For the updated pulse amplitude, the first The pulse period during each adjustment. This is the gain coefficient. Amplitude is a core parameter affecting the intensity of the supersaturation impact. If it's too small, the target salt cannot nucleate; if it's too large, it may induce impurity co-precipitation. Adaptive adjustment requires incremental changes based on the current value, therefore the amplitude from the previous moment must be remembered. Selectivity factor is a direct indicator of pulse effect. When the measured selectivity is lower than the target, the deviation is positive, requiring an increase in amplitude to enhance the excitation of the target salt; the deviation is negative, requiring a decrease in amplitude. Period determines the pulse repetition frequency. If the period is too long, the number of pulses per unit time is low, resulting in low crystallization efficiency; if the period is too short, the supersaturation from the previous pulse has not yet recovered, causing baseline drift. Adaptive adjustment requires correction based on the current period. Amplitude mainly affects the peak supersaturation value and is suitable for rapid response to a decrease in selectivity, immediately enhancing or weakening the impact. Period mainly affects the pulse frequency and recovery time and is suitable for compensating for long-term drift.

[0073] PID closed-loop control is used instead of open-loop control because open-loop control cannot overcome practical problems such as actuator drift, changes in brine properties, environmental disturbances, and hysteresis, which can lead to pulse waveform distortion and compromise selectivity. The proportional element of the PID controller responds quickly to deviations, ensuring close tracking of the steep rising edge; the integral element eliminates steady-state errors, ensuring accurate and stable holding; and the derivative element suppresses overshoot and undershoot, guaranteeing a smooth transition of the gentle falling edge. These three elements work together to reliably and accurately reproduce the "steep rise, gentle fall" asymmetric pulse waveform in a simple, robust, and model-free industrial standard manner, providing engineering assurance for selective salt precipitation.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation, characterized in that, Includes the following steps: S1. Apply a short-time step perturbation to the brine and calculate the characteristic response time of the dominant salts in the brine. ; S2. Based on the difference between the target salt and the impurity salt, design a periodic asymmetric pulse waveform with parameters that satisfy the selectivity condition. S3. During the salt precipitation process, the controller automatically generates a continuous pulse waveform according to a preset cycle and calculates the target value in real time using a piecewise function. , The actual value is tracked by the target waveform using PID closed-loop control, so that the target salt is preferentially nucleated on each pulse rising edge, while the impurity salt is suppressed due to the response lag. S4. Monitor the conductivity response after the pulse in real time and calculate the pulse response intensity. The selectivity factor was calculated by alternately applying high-frequency and low-frequency pulses. and the target selectivity factor Compare; S5. Adjust the pulse amplitude according to the adaptive law. and pulse period ,make Simultaneously monitor the second derivative of conductivity. Early warning of impurity nucleation; S6. Once the cumulative crystallization amount of the target salt reaches the target, solid-liquid separation is performed to obtain high-purity crystals.

2. The selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation according to claim 1, characterized in that, The characteristic response time of the dominant salt The calculation formula is: ， in, For characteristic response time, Real-time conductivity For steady-state conductivity, This represents the change in peak conductivity. The characteristic response time of the salt to be identified, This is the time elapsed from the moment of the disturbance to the present moment.

3. The selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation according to claim 1, characterized in that, The selectivity condition satisfied by the S2 parameter is: ， in, The characteristic response time of the target salt. The pulse rise time, The pulse hold time, This represents the characteristic response time of the impurity salt.

4. The selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation according to claim 1, characterized in that, In S3 The calculation formula is: ， in, For a moment The target pH value, Baseline pH value This is the start time of the current pulse cycle. The duration of the pH decrease, The duration of the pH rise. For pH to remain stable, For pulse period, The pulse amplitude. The rising edge shape index, The falling edge shape index.

5. The selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation according to claim 1, characterized in that, In S3 The calculation formula is: ， in, For a moment Target temperature Baseline temperature The amplitude of the temperature pulse. For a moment The target pH value, This is the start time of the current pulse cycle. The duration of the temperature drop. The duration of the temperature rise. For the time it takes for the temperature to remain stable, For pulse period, The coupling coefficient between pH and temperature during the heating phase. The coupling coefficient between pH and temperature during the cooling phase. To cool along the shape index, To increase the temperature along the shape index, This refers to the duration of the slow heating process.

6. The selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation according to claim 1, characterized in that, The impulse response intensity in S4 The calculation formula is: ， in, The impulse response intensity, The conductivity at the start of the pulse. For real-time conductivity, For fractional order, The attenuation coefficient is... For continuous response time, The characteristic response time of the target salt is determined by calculating the selectivity factor through alternating application of high-frequency and low-frequency pulses. The calculation formula is: ， in, As a selectivity factor, The angular frequency under high-frequency pulses, The angular frequency under low-frequency pulses, For system transfer function, The phase sensitivity coefficient, This represents the phase lag difference between high and low frequencies. As a reference phase difference, The average characteristic response time, For the pulse to change steeply along its duration, The pulse hold time, This is the matching ratio index.

7. The selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation according to claim 1, characterized in that, In step S5, the pulse amplitude is adjusted according to the adaptive law. The calculation formula is: ， in, The updated pulse amplitude, For the first Pulse amplitude during the next adjustment For target selectivity factor, For the first The target selectivity factor was measured after the second pulse ended. The gain coefficient is used to adjust the pulse period according to the adaptive law. The calculation formula is: ， in, For the updated pulse period, the first The pulse period during each adjustment. This is the gain coefficient.

8. The selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation according to claim 1, characterized in that, The conditions for impurity nucleation early warning in S5 are as follows: ， in, The second derivative of conductivity. , The standard deviation of the second derivative when there are no impurities is given. Reduce the amplitude or extend the smoothing segment.

9. The selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation according to claim 1, characterized in that, The pH pulse is transmitted through... or remove The temperature pulse is achieved through heating or cooling.

10. The selective brine salt precipitation method based on pH and temperature synergistic pulse oscillation according to claim 1, characterized in that, The brine is natural salt lake brine, underground brine, seawater desalination concentrated brine, or industrial saline wastewater; the target salt is one or more of sodium chloride, potassium chloride, lithium carbonate, magnesium sulfate, and borate.

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