On-line monitoring of key ion concentration in synthesis of trimanganese tetraoxide

Abstract

This invention belongs to the field of manganese tetroxide (MnO) synthesis technology. It provides an online monitoring method for the concentration of key ions during the MnO synthesis process. The method includes: acquiring the backscattered light intensity signal of the slurry using an online process analyzer; obtaining the intermediate concentration using a preset correlation model; calculating the correlation rate based on the conservation of manganese atoms; determining whether a capping layer has formed; if so, deploying a pulse rinsing unit to clean the electrode surface; obtaining the first measurement result of the key ion concentration after cleaning; determining whether the capping layer has completely detached based on the synchronous deviation trend; if not completely detached, increasing the rinsing frequency for a second cleaning and retesting; and finally, using the corresponding first measurement result as the true key ion concentration after complete detachment. This method eliminates the need for complex algorithms or high-cost modifications, reducing equipment wear and monitoring costs, and ensuring the reaction process and product purity stability of MnO synthesis.

Description

Technical Field

[0001] This invention belongs to the field of manganese tetroxide synthesis technology, specifically an online monitoring method for the concentration of key ions during the synthesis of manganese tetroxide. Background Technology

[0002] Currently, the most mainstream synthesis method for high-purity manganese tetroxide in industrial production is the liquid-phase oxidation method (also known as the hydroxide oxidation method). The core process of this method involves reacting manganese salts (such as common manganese sources like manganese sulfate) with alkaline substances (such as sodium hydroxide, ammonia, etc.) to produce... The suspension was then directed towards High-purity manganese tetroxide is prepared by introducing air or oxygen into a suspension and then reacting it with an oxidation reaction.

[0003] In the production process of the above-mentioned liquid-phase oxidation method and Changes in the concentration of [a specific substance] directly affect the reaction process, product purity, and reaction efficiency; therefore, it is necessary to monitor the concentration of [a specific substance] in the slurry within the reactor. and Concentration is monitored online. In existing technologies, the conventional approach to online monitoring is to directly insert sensors (such as ion-selective electrodes, redox electrodes, etc.) into the slurry in the reactor and read the concentration data directly through the sensors.

[0004] Currently, most technological research in the industry focuses on improving sensor detection accuracy and enhancing their resistance to electromagnetic interference to optimize concentration monitoring. However, it neglects a crucial physicochemical phenomenon—the colloidal shielding effect of the microenvironment on the electrode surface. Specifically, in Towards During the oxidation process of transformation, the reaction is not completed in one step, but rather proceeds through a series of intermediate states (such as...). (Colloids, etc.). These intermediate colloids are highly viscous and readily adsorb onto the sensitive membrane surface of the sensor during the reaction, forming an extremely thin microenvironment coating layer.

[0005] The aforementioned microenvironment coating layer can severely impact the monitoring of key ion concentrations: the interior of the coating layer... and Changes in concentration lag significantly behind changes in concentration in the main slurry of the reactor. Therefore, the data directly read by the sensor is not the current true concentration data within the reactor, but rather outdated data, leading to distortion in the monitoring results of key ion concentrations.

[0006] The conventional solutions used in existing technologies are cumbersome and have limitations: most of them attempt to correct hysteresis errors by increasing the sampling frequency of sensors or using complex algorithms to compensate and predict the monitoring data. However, increasing the sampling frequency will increase equipment wear and monitoring costs, while complex algorithm compensation requires big data processing technology, which not only increases the system complexity and R&D costs, but also makes it difficult to accurately correct hysteresis errors. It cannot fundamentally solve the monitoring problem caused by the colloidal shielding effect of the microenvironment, which has become a technical pain point that urgently needs to be solved in the existing liquid phase oxidation method for preparing high-purity manganese tetroxide.

[0007] Therefore, the present invention provides an online monitoring method for the concentration of key ions during the synthesis of manganese tetroxide. Summary of the Invention

[0008] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0009] The technical solution adopted by this invention to solve its technical problem is:

[0010] One of the objectives of this invention is to provide an online monitoring method for the concentration of key ions during the synthesis of manganese tetroxide, comprising the following steps:

[0011] Step S10: Obtain the intermediate state concentration during the synthesis of manganese tetroxide by liquid-phase oxidation, analyze the relationship between the intermediate state concentration and the change in the mass of manganese tetroxide precipitate, determine whether the intermediate colloid will coat the ion sensor electrode to form a capping layer, and if a capping layer is formed, arrange a pulse scouring unit on the surface of the ion sensor electrode.

[0012] Step S20: Use the pulse flushing unit to clean the surface of the ion sensor electrode to remove the capping layer, obtain the first key ion concentration measurement result after the capping layer is removed from the ion sensor electrode surface, and analyze the relationship between the key ion concentration measurement result and the mass change of manganese tetroxide precipitate to determine whether the capping layer has completely detached from the ion sensor electrode surface.

[0013] Step S30: If the coating layer is not completely removed from the ion sensor electrode surface, increase the cleaning frequency of the pulse flushing unit to perform a second cleaning on the ion sensor electrode surface, obtain the first key ion concentration measurement result after the second cleaning, and determine again whether the coating layer is completely removed from the ion sensor electrode surface.

[0014] Step S40: If the coating is completely removed from the ion sensor electrode surface, the first critical ion concentration measurement result after the coating is completely removed from the ion sensor electrode surface shall be taken as the true critical ion concentration.

[0015] As a further improvement of the present invention, the specific process for obtaining the intermediate state concentration in the process of synthesizing manganese tetroxide by liquid-phase oxidation is as follows:

[0016] A correlation model between backscattered light intensity signal value and intermediate state concentration was established. The backscattered light intensity signal value of the slurry was continuously collected by an online process analyzer and substituted into the correlation model between backscattered light intensity signal value and intermediate state concentration to output the intermediate state concentration in the process of synthesizing manganese tetroxide by liquid phase oxidation in real time.

[0017] As a further improvement of the present invention, the specific process of establishing the correlation model between backscattered light intensity signal value and intermediate state concentration is as follows:

[0018] An online process analyzer is installed on the slurry circulation pipeline of the reactor. Multiple sets of intermediate slurries with known concentrations are prepared first. The backscattered light intensity signal corresponding to each intermediate slurry is continuously collected by the online process analyzer. A correlation model between the backscattered light intensity signal value and the intermediate concentration is established by the least squares method.

[0019] As a further improvement of the present invention, the specific process for determining whether the intermediate-state colloid will encapsulate the ion sensor electrode to form a capping layer is as follows:

[0020] The intermediate concentration, the mass of manganese tetroxide precipitate, and the concentration of key ions measured by the ion sensor are obtained. The calculation window is set within the calculation window. The equivalent rate based on the change in the molar flow rate of manganese in the calculation window is used to calculate the formation rate of intermediate colloid, the net formation rate of manganese tetroxide precipitate, and the apparent consumption rate of key ion concentration.

[0021] If the absolute value of the apparent consumption rate of the key ion concentration is less than the sum of the net formation rate of manganese tetroxide precipitate and the formation rate of intermediate colloid, it is determined that a capping layer has formed.

[0022] As a further improvement of the present invention, the specific process of determining whether the intermediate colloid will encapsulate the ion sensor electrode to form a capping layer further includes:

[0023] If the absolute value of the apparent consumption rate of the key ion concentration is greater than or equal to the sum of the net formation rate of manganese tetroxide precipitate and the formation rate of intermediate colloids, and the fluctuation range is within the error threshold, it is determined that no capping layer has been formed.

[0024] As a further improvement of the present invention, the specific process of arranging the pulse flushing unit on the surface of the ion sensor electrode is as follows:

[0025] After determining that a coating layer has been formed, a pulse rinsing unit is arranged on the outside of the sensitive film on the surface of the ion sensor electrode. The core actuator of the pulse rinsing unit is a corrosion-resistant micro-nozzle. The corrosion-resistant micro-nozzle is aligned with the sensitive film on the surface of the ion sensor electrode in a ring array. The liquid inlet pipe of the corrosion-resistant micro-nozzle is connected to the impurity-free deionized water / process mother liquor that is matched with the reactor. A pulse control valve is configured on the liquid inlet pipe.

[0026] As a further improvement of the present invention, the specific process for obtaining the first key ion concentration measurement result after the coating layer is removed from the ion sensor electrode surface is as follows:

[0027] The corrosion-resistant micro-nozzle of the pulse rinsing unit sprays impurity-free deionized water or process mother liquor onto the sensitive membrane surface of the ion sensor electrode. The sensitive membrane on the ion sensor electrode surface is cleaned using preset pulse parameters. After cleaning is stopped, the membrane is left to stand for a preset time, and the first measurement of the key ion concentration is performed to obtain the first key ion concentration measurement result on the ion sensor electrode surface after the coating layer is removed.

[0028] As a further improvement of the present invention, the specific process for determining whether the covering layer has completely detached from the ion sensor electrode surface is as follows:

[0029] The first key ion concentration measurement results, manganese tetroxide precipitate mass, and backscattered light intensity signal corresponding to the intermediate slurry were obtained from the ion sensor and converted into a unified molar flow rate change rate. The apparent consumption rate of key ion concentration, net formation rate of manganese tetroxide precipitate, and formation rate of intermediate colloid were calculated.

[0030] The synchronization deviation is calculated as the sum of the apparent consumption rate and the theoretical formation rate of the key ion concentration. Synchronization deviation = apparent consumption rate of key ion concentration - net formation rate of manganese tetroxide precipitate - formation rate of intermediate colloid.

[0031] Set up a collection window and divide it into N sampling points. Obtain the synchronization deviation corresponding to the apparent consumption rate of the key ion concentration at each sampling point. If the synchronization deviation value of each sampling point is less than the synchronization deviation of the previous sampling point, it is determined that the capping layer has completely detached. Otherwise, it is determined that the capping layer has not completely detached.

[0032] As a further improvement of the present invention, the specific process of performing secondary cleaning on the surface of the ion sensor electrode is as follows:

[0033] If it is determined that the coating layer has not completely detached, the production line DCS control system increases the cleaning frequency of the pulse rinsing unit. Based on the original preset pulse rinsing frequency, it is adjusted upwards by gradient and the adjusted pulse rinsing unit is started to perform secondary pulse cleaning on the surface of the sensitive membrane of the ion sensor electrode.

[0034] As a further improvement of the present invention, the specific process of taking the first critical ion concentration measurement result after the coating layer is completely removed from the ion sensor electrode surface as the true critical ion concentration is as follows:

[0035] If the determination result is that the capping layer has been completely removed, the first critical ion concentration measurement result detected by the ion sensor will be recorded as the current true critical ion concentration in the reactor.

[0036] The second objective of this invention is to provide an online monitoring system for the concentration of key ions during the synthesis of manganese tetroxide, comprising the following modules:

[0037] Intermediate state concentration acquisition and capping layer determination module: acquires the intermediate state concentration during the synthesis of manganese tetroxide by liquid phase oxidation, analyzes the relationship between the intermediate state concentration and the change in the mass of manganese tetroxide precipitate, determines whether the intermediate colloid will coat the ion sensor electrode to form a capping layer, and if a capping layer is formed, arranges a pulse scouring unit on the surface of the ion sensor electrode.

[0038] Initial concentration detection and cleaning module: The pulse flushing unit is used to clean the surface of the ion sensor electrode to remove the capping layer. The first key ion concentration measurement results after the capping layer is removed are obtained from the ion sensor electrode surface. The relationship between the key ion concentration measurement results and the mass change of manganese tetroxide precipitate is analyzed to determine whether the capping layer has completely detached from the ion sensor electrode surface.

[0039] Secondary cleaning and concentration retest module: If the coating layer is not completely removed from the ion sensor electrode surface, the cleaning frequency of the pulse flushing unit is increased to perform secondary cleaning on the ion sensor electrode surface, and the first key ion concentration measurement result after secondary cleaning is obtained, and it is determined again whether the coating layer is completely removed from the ion sensor electrode surface.

[0040] True critical ion concentration locking module: If the ion sensor electrode is completely removed, the first critical ion concentration measurement result after the coating layer is completely removed from the ion sensor electrode will be taken as the true critical ion concentration.

[0041] The beneficial effects of this invention are as follows:

[0042] 1. Addressing the core pain point in existing technologies where ion sensor electrodes are easily adsorbed by intermediate-state colloids, forming a capping layer that leads to delayed monitoring of key ion concentrations and data distortion, this invention monitors the intermediate-state concentration online and determines the capping layer formation status. It then uses a pulse scouring unit to precisely remove the capping layer and verifies the removal effect by combining the synchronization deviation trend. This eliminates colloidal shielding interference at the physical level, enabling the ion sensor to provide real-time feedback on the true key ion concentration of the reactor body. This significantly outperforms the correction effects of existing algorithm compensation or frequency-increased sampling.

[0043] 2. The online process analyzer is connected to the existing slurry circulation pipeline of the reactor via a flange. The pulse flushing unit is fixed with a clamp-type quick-connect structure, which does not require modification of the reactor body and ion sensor electrodes, and is compatible with existing liquid phase oxidation production lines. The core components (corrosion-resistant micro-nozzle and online process analyzer) are all made of mature materials resistant to manganese salt-alkaline slurry corrosion, and do not rely on big data processing equipment. The modification cost is low, the maintenance is simple, and it can be quickly deployed to industrial production.

[0044] 3. The entire process is linked through the production line DCS control system to achieve an automated closed loop of intermediate concentration acquisition, coating layer determination, pulse flushing, and concentration retesting without manual intervention. The pulse flushing adopts a micro-flow and low-intensity gradient frequency increase design, which ensures effective removal of the coating layer while avoiding damage to the electrode sensitive film or excessive disturbance to the slurry system. Compared with the existing technology of increasing the sampling frequency, it significantly reduces the wear and tear of equipment such as ion sensors and reduces monitoring and maintenance costs.

[0045] 4. Accurate and accurate key ion concentration data provide a reliable basis for parameter control in the synthesis process of manganese tetroxide, effectively avoiding reaction process disorder caused by concentration monitoring distortion, ensuring stable conversion of intermediate colloids into target products, thereby improving the purity consistency and batch stability of manganese tetroxide products, and meeting the industrial production requirements of high-purity manganese tetroxide.

[0046] 5. No complex algorithm modeling or redundant detection steps are required. The rate correlation model is established through the conservation of manganese atoms, and the judgment logic is clear and the response is rapid. The pulse scouring medium uses impurity-free deionized water or process mother liquor matched with the reactor, without the introduction of additional impurities, and will not cause secondary interference to the synthesis reaction, thus balancing monitoring accuracy and process safety. Attached Figure Description

[0047] The invention will now be further described with reference to the accompanying drawings.

[0048] Figure 1 This is a flowchart illustrating the steps of online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to the present invention.

[0049] Figure 2 This is a system module diagram of online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to the present invention. Detailed Implementation

[0050] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0051] Example 1

[0052] like Figure 1As shown in the embodiment of the present invention, online monitoring of key ion concentrations during the synthesis of manganese tetroxide includes the following steps:

[0053] Step S10: Obtain the intermediate state concentration during the synthesis of manganese tetroxide by liquid-phase oxidation, analyze the relationship between the intermediate state concentration and the change in the mass of manganese tetroxide precipitate, determine whether the intermediate colloid will coat the ion sensor electrode to form a capping layer, and if a capping layer is formed, arrange a pulse scouring unit on the surface of the ion sensor electrode.

[0054] In step S10, the specific process for obtaining the intermediate concentration in the liquid-phase oxidation process for synthesizing manganese tetroxide is as follows:

[0055] The detection probe of the online process analyzer is arranged on the slurry circulation pipeline of the reactor via a flange connection. The detection probe is made of polytetrafluoroethylene / 316L stainless steel to withstand the corrosive environment of manganese salt-alkaline slurry. The online process analyzer is a static light scattering instrument adapted to high-concentration slurry. The backscattered light intensity at a specific angle of the online process analyzer is extremely sensitive to changes in the number and concentration of submicron colloidal particles.

[0056] The online process analyzer establishes real-time data communication with the production line DCS control system. During the synthesis process of manganese tetroxide, the online process analyzer continuously collects the backscattered light intensity signal of the slurry. The backscattered light intensity signal is positively correlated with the number and concentration of intermediate particles such as hydroxyl manganese colloid in the slurry.

[0057] First, multiple sets of intermediate slurries with known concentrations were prepared. The backscattered light intensity signal corresponding to each intermediate slurry was continuously collected by an online process analyzer. Since the backscattered light intensity signal is positively correlated with the number and concentration of intermediate particles such as hydroxyl manganese colloid in the slurry, a correlation model between the backscattered light intensity signal value and the intermediate concentration was established by the least squares method.

[0058] During the synthesis process of manganese tetroxide, the online process analyzer continuously collects the backscattered light intensity signal value of the slurry. Substitutes it into the above-mentioned backscattered light intensity signal value-intermediate state concentration correlation model, and outputs the intermediate state concentration in the process of synthesizing manganese tetroxide by liquid phase oxidation in real time.

[0059] In step S10, the specific process of analyzing the relationship between the intermediate state concentration and the change in the mass of manganese tetroxide precipitate, and determining whether the intermediate colloid will encapsulate the ion sensor electrode to form a capping layer, is as follows:

[0060] The intermediate concentration collected by the online process analyzer, the mass of manganese tetroxide precipitate obtained through material conservation calculations or online solid content detection of the reaction system, and the concentration of key ions measured by the ion sensor were acquired simultaneously. In the same coordinate system, curves showing the changes in intermediate concentration, manganese tetroxide precipitate mass, and key ion concentration were established. Analysis of these curves revealed a positive correlation between intermediate concentration and manganese tetroxide precipitate mass, and a positive correlation between intermediate concentration and key ion concentration (including...). and The changes in ) are negatively correlated;

[0061] Set a calculation window (the calculation window duration can be set to 1 minute, depending on the process duration and acquisition frequency). Within the calculation window, based on the principle of atomic conservation of manganese, uniformly convert to an equivalent rate based on the change in molar flow rate of manganese within the calculation window. Calculate the formation rate of intermediate colloids (the ratio of the difference between the intermediate concentration at the end of the calculation window and the intermediate concentration at the beginning of the calculation window to the calculation window), the net formation rate of manganese tetroxide precipitate (the ratio of the difference between the mass of manganese tetroxide precipitate at the end of the calculation window and the mass of manganese tetroxide precipitate at the beginning of the calculation window to the calculation window), and the apparent consumption rate of key ion concentration (the ratio of the difference between the key ion concentration at the end of the calculation window and the key ion concentration at the beginning of the calculation window to the calculation window; if negative, take the absolute value).

[0062] According to the reaction pathway of the liquid-phase oxidation method, the consumption of key ions is mainly used to generate intermediate colloids, which are then continuously converted into manganese tetroxide precipitate. Therefore, under ideal, undisturbed conditions, the dynamic equilibrium relationship should be satisfied: the apparent consumption rate of key ion concentration = the net generation rate of manganese tetroxide precipitate + the generation rate of intermediate colloids.

[0063] If the absolute value of the apparent consumption rate of the key ion concentration is less than the sum of the net formation rate of manganese tetroxide precipitate and the formation rate of intermediate colloid, it indicates that the consumption rate fed back by the ion sensor is lower than the actual reaction consumption rate. This difference is attributed to the concentration diffusion barrier created by the colloidal coating layer formed on the electrode surface, which causes the sensor monitoring value to lag behind the true value of the reaction body. It is determined that the intermediate colloid will wrap around the ion sensor electrode to form a coating layer.

[0064] If the absolute value of the apparent consumption rate of the key ion concentration is greater than or equal to the sum of the net formation rate of manganese tetroxide precipitate and the formation rate of intermediate colloid, and the fluctuation range (fluctuation range = apparent consumption rate of key ion concentration - net formation rate of manganese tetroxide precipitate - formation rate of intermediate colloid) is within the error threshold (e.g., ±5%), it indicates that the ion sensor responds promptly and is not significantly interfered with by the colloidal coating layer.

[0065] In step S10, if a capping layer is formed, the specific process of arranging the pulse scouring unit on the surface of the ion sensor electrode is as follows:

[0066] After determining that the intermediate colloid will coat the ion sensor electrode to form a covering layer, a pulse rinsing unit is arranged on the outside of the sensitive film on the surface of the ion sensor electrode. The core actuating component of the pulse rinsing unit is a corrosion-resistant micro-nozzle. The corrosion-resistant micro-nozzle is made of polytetrafluoroethylene / 316L stainless steel and is suitable for the corrosion reaction system of manganese salt-alkaline slurry.

[0067] The corrosion-resistant micro-nozzles are precisely aligned with the sensitive film on the surface of the ion sensor electrode in a ring array to ensure that the rinsing range fully covers the sensitive film area of ​​the electrode without any dead corners. The corrosion-resistant micro-nozzles are fixedly connected to the mounting base on the surface of the ion sensor electrode through a clamp-type quick-connect structure, without the need to modify the ion sensor electrode body or the existing installation structure inside the reactor.

[0068] The liquid inlet pipe of the corrosion-resistant micro-nozzle is connected to the impurity-free deionized water / process mother liquor storage unit of the reactor. A pulse control valve is configured on the liquid inlet pipe. The pulse control valve establishes a communication connection with the production line DCS control system and is linked with the detection data of the ion sensor and the online nanoparticle size analyzer.

[0069] After completing the assembly of the corrosion-resistant micro-nozzle, liquid inlet pipeline and pulse control valve, the pulse control valve is turned on to perform a single micro-flow test flush to confirm that the micro-nozzle outflow is uniform, the flushing range accurately covers the electrode sensitive film and there is no excessive disturbance to the surrounding slurry. This completes the arrangement of the pulse flushing unit on the surface of the ion sensor electrode.

[0070] Step S20: Use the pulse flushing unit to clean the surface of the ion sensor electrode to remove the capping layer, obtain the first key ion concentration measurement result after the capping layer is removed from the ion sensor electrode surface, and analyze the relationship between the key ion concentration measurement result and the mass change of manganese tetroxide precipitate to determine whether the capping layer has completely detached from the ion sensor electrode surface.

[0071] In step S20, the surface of the ion sensor electrode is cleaned using a pulse flushing unit to remove the capping layer. The specific process for obtaining the first key ion concentration measurement result after the capping layer is removed from the ion sensor electrode surface is as follows:

[0072] The pulse control valve linked to the production line DCS control system is activated to control the corrosion-resistant micro-nozzle of the pulse rinsing unit to spray impurity-free deionized water or process mother liquor onto the sensitive membrane surface of the ion sensor electrode. Preset pulse parameters (pulse frequency and rinsing flow rate adapted to the cleaning requirements of the cover layer and linked with the preset threshold of the DCS control system) are used to perform targeted cleaning of the sensitive membrane surface of the ion sensor electrode. During the cleaning process, a low-flow, low-intensity pulse rinsing is maintained to ensure that the rinsing force is sufficient to completely remove the intermediate colloidal cover layer on the surface of the sensitive membrane, while avoiding excessive disturbance to the surrounding slurry on the surface of the ion sensor electrode and damage to the electrode sensitive membrane.

[0073] Continue cleaning until the DCS control system detects a significant change in the real-time signal of the ion sensor (indicating that the coating has initially detached). Immediately close the pulse control valve and stop the pulse flushing operation. After cleaning is stopped, let it stand for a preset time (e.g., 0.5~1 min) to allow the slurry around the sensitive film on the surface of the ion sensor electrode to complete mass transfer with the slurry in the main body of the reactor and for the concentration to become uniform, so as to avoid the flushing disturbance from interfering with the concentration measurement.

[0074] Then, the ion sensor is activated to perform the first measurement of the critical ion concentration. The ion sensor quickly transmits the real-time critical ion concentration data to the production line DCS control system. This detection data is the first critical ion concentration measurement result on the surface of the ion sensor electrode after the cover layer is removed.

[0075] In step S20, the specific process of analyzing the relationship between the key ion concentration measurement results and the mass change of manganese tetroxide precipitate to determine whether the coating layer has completely detached from the ion sensor electrode surface is as follows:

[0076] The system simultaneously acquires the initial key ion concentration measurement results, manganese tetroxide precipitate mass, and backscattered light intensity signal corresponding to the intermediate slurry detected by the ion sensor. Based on the principle of manganese atom conservation, the initial key ion concentration measurement results, manganese tetroxide precipitate mass, and backscattered light intensity signal corresponding to the intermediate slurry are converted into a unified molar flow rate change rate in real time. The apparent consumption rate of key ion concentration, net formation rate of manganese tetroxide precipitate, and formation rate of intermediate colloid are calculated.

[0077] The synchronization deviation is calculated as the sum of the apparent consumption rate and the theoretical formation rate of the key ion concentration. Synchronization deviation = apparent consumption rate of key ion concentration - net formation rate of manganese tetroxide precipitate - formation rate of intermediate colloid.

[0078] Set a collection window (e.g., 3 minutes), and divide the collection window into N sampling points (N is 3 in this invention). Obtain the synchronization deviation corresponding to the apparent consumption rate of the key ion concentration at each sampling point. If the synchronization deviation is continuously decreasing, that is, the synchronization deviation value corresponding to each sampling point is less than the synchronization deviation corresponding to the previous sampling point, this indicates that the covering layer on the surface of the ion sensor electrode has been removed, and the key ion concentration on the surface of the ion sensor electrode has been synchronized with the concentration of the reactor body. Then it is determined that the covering layer has been completely removed, and the ion sensor has resumed normal monitoring.

[0079] Conversely, it is determined that the coating layer has not completely detached from the surface of the ion sensor electrode;

[0080] Step S30: If the coating layer is not completely removed from the ion sensor electrode surface, increase the cleaning frequency of the pulse flushing unit to perform a second cleaning on the ion sensor electrode surface, obtain the first key ion concentration measurement result after the second cleaning, and determine again whether the coating layer is completely removed from the ion sensor electrode surface.

[0081] In step S30, if the electrode is not completely removed from the ion sensor electrode surface, the cleaning frequency of the pulse flushing unit is increased to perform a secondary cleaning of the ion sensor electrode surface. The specific process is as follows:

[0082] If it is determined that the coating layer has not completely detached from the surface of the ion sensor electrode, the production line DCS control system will automatically increase the cleaning frequency of the pulse flushing unit. The frequency will be increased in a gradient (e.g., by 20%) based on the original preset pulse flushing frequency. The flushing medium, the flushing range of the corrosion-resistant micro-nozzle, and the flushing principle of low intensity and micro-flow will remain unchanged. This will ensure that the frequency increase only increases the cleaning frequency and does not increase the single flushing force, thus avoiding damage to the electrode sensitive film or excessive disturbance to the surrounding slurry.

[0083] The adjusted pulse rinsing unit is then activated to perform a secondary pulse cleaning on the surface of the sensitive membrane of the ion sensor electrode until the preset secondary cleaning cycle is completed and then the rinsing stops.

[0084] In step S30, the specific process of obtaining the first key ion concentration measurement result after the second cleaning and determining again whether the coating layer has completely detached from the ion sensor electrode surface is as follows:

[0085] After cleaning is stopped, the mixture is left to stand for a preset time until the slurry around the electrode sensitive membrane and the slurry in the main body of the reactor complete mass transfer and the concentration is restored to uniformity. Then, the ion sensor is started to detect the concentration of key ions, and the first measurement result of the concentration of key ions after the second cleaning is collected and recorded and transmitted to the DCS control system.

[0086] And again determine whether the coating layer on the surface of the ion sensor electrode has completely detached (same as step S20), until the determination result is that the coating layer has completely detached from the surface of the ion sensor electrode.

[0087] Step S40: If the coating is completely removed from the ion sensor electrode surface, the first critical ion concentration measurement result after the coating is completely removed from the ion sensor electrode surface shall be taken as the true critical ion concentration.

[0088] In step S40, if the coating layer is completely detached from the ion sensor electrode surface, the specific process of taking the first critical ion concentration measurement result after the coating layer is completely detached from the ion sensor electrode surface as the true critical ion concentration is as follows:

[0089] If the determination result is that the coating has completely detached from the surface of the ion sensor electrode, the production line DCS control system will automatically lock the first key ion concentration measurement result detected by the ion sensor after the coating is determined to be completely detached; then the validity of the first measurement result will be verified to confirm that its data fluctuation is within the preset error range (the deviation from the theoretical key ion concentration calculated by the atomic conservation of the reaction system is ≤±1%), and that it maintains a theoretical match with the real-time acquisition of the manganese tetroxide precipitation mass change rate, eliminating interference factors such as abnormal measurement data and slurry disturbance;

[0090] After the verification is passed, the DCS control system marks the initial critical ion concentration measurement result as the current true critical ion concentration in the reactor, and continues to collect the true critical ion concentration data until the manganese tetroxide synthesis process is completed.

[0091] Example 2

[0092] like Figure 2 As shown, based on the specific implementation process of Example 1, the present invention provides an online monitoring method for the concentration of key ions during the synthesis of manganese tetroxide, including the following modules:

[0093] Intermediate state concentration acquisition and capping layer determination module: acquires the intermediate state concentration during the synthesis of manganese tetroxide by liquid phase oxidation, analyzes the relationship between the intermediate state concentration and the change in the mass of manganese tetroxide precipitate, determines whether the intermediate colloid will coat the ion sensor electrode to form a capping layer, and if a capping layer is formed, arranges a pulse scouring unit on the surface of the ion sensor electrode.

[0094] Initial concentration detection and cleaning module: The pulse flushing unit is used to clean the surface of the ion sensor electrode to remove the capping layer. The first key ion concentration measurement results after the capping layer is removed are obtained from the ion sensor electrode surface. The relationship between the key ion concentration measurement results and the mass change of manganese tetroxide precipitate is analyzed to determine whether the capping layer has completely detached from the ion sensor electrode surface.

[0095] Secondary cleaning and concentration retest module: If the coating layer is not completely removed from the ion sensor electrode surface, the cleaning frequency of the pulse flushing unit is increased to perform secondary cleaning on the ion sensor electrode surface, and the first key ion concentration measurement result after secondary cleaning is obtained, and it is determined again whether the coating layer is completely removed from the ion sensor electrode surface.

[0096] True critical ion concentration locking module: If the ion sensor electrode is completely removed, the first critical ion concentration measurement result after the coating layer is completely removed from the ion sensor electrode will be taken as the true critical ion concentration.

[0097] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An online monitoring method for the concentration of key ions during the synthesis of manganese tetroxide, characterized in that: include: Step S10: Obtain the intermediate state concentration during the synthesis of manganese tetroxide by liquid-phase oxidation, analyze the relationship between the intermediate state concentration and the change in the mass of manganese tetroxide precipitate, determine whether the intermediate colloid will coat the ion sensor electrode to form a capping layer, and if a capping layer is formed, arrange a pulse scouring unit on the surface of the ion sensor electrode. Step S20: Use the pulse flushing unit to clean the surface of the ion sensor electrode to remove the capping layer, obtain the first key ion concentration measurement result after the capping layer is removed from the ion sensor electrode surface, and analyze the relationship between the key ion concentration measurement result and the mass change of manganese tetroxide precipitate to determine whether the capping layer has completely detached from the ion sensor electrode surface. Step S30: If the coating layer is not completely removed from the ion sensor electrode surface, increase the cleaning frequency of the pulse flushing unit to perform a second cleaning on the ion sensor electrode surface, obtain the first key ion concentration measurement result after the second cleaning, and determine again whether the coating layer is completely removed from the ion sensor electrode surface. Step S40: If the coating is completely removed from the ion sensor electrode surface, the first critical ion concentration measurement result after the coating is completely removed from the ion sensor electrode surface shall be taken as the true critical ion concentration.

2. The online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to claim 1, characterized in that: The specific process for obtaining the intermediate state concentration in the liquid-phase oxidation synthesis of manganese tetroxide is as follows: A correlation model between backscattered light intensity signal value and intermediate state concentration was established. The backscattered light intensity signal value of the slurry was continuously collected by an online process analyzer and substituted into the correlation model between backscattered light intensity signal value and intermediate state concentration to output the intermediate state concentration in the process of synthesizing manganese tetroxide by liquid phase oxidation in real time.

3. The online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to claim 2, characterized in that: The specific process for establishing the correlation model between backscattered light intensity signal value and intermediate state concentration is as follows: An online process analyzer is installed on the slurry circulation pipeline of the reactor. Multiple sets of intermediate slurries with known concentrations are prepared first. The backscattered light intensity signal corresponding to each intermediate slurry is continuously collected by the online process analyzer. A correlation model between the backscattered light intensity signal value and the intermediate concentration is established by the least squares method.

4. The online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to claim 1, characterized in that: The specific process for determining whether the intermediate-state colloid will encapsulate the ion sensor electrode to form a capping layer is as follows: The intermediate concentration, the mass of manganese tetroxide precipitate, and the concentration of key ions measured by the ion sensor are obtained. The calculation window is set within the calculation window. The equivalent rate based on the change in the molar flow rate of manganese in the calculation window is used to calculate the formation rate of intermediate colloid, the net formation rate of manganese tetroxide precipitate, and the apparent consumption rate of key ion concentration. If the absolute value of the apparent consumption rate of the key ion concentration is less than the sum of the net formation rate of manganese tetroxide precipitate and the formation rate of intermediate colloid, it is determined that a capping layer has formed.

5. The online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to claim 4, characterized in that: The specific process for determining whether the intermediate-state colloid will encapsulate the ion sensor electrode to form a capping layer also includes: If the absolute value of the apparent consumption rate of the key ion concentration is greater than or equal to the sum of the net formation rate of manganese tetroxide precipitate and the formation rate of intermediate colloids, and the fluctuation range is within the error threshold, it is determined that no capping layer has been formed.

6. The online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to claim 1, characterized in that: The specific process of arranging the pulse flushing unit on the surface of the ion sensor electrode is as follows: After determining that a coating layer has been formed, a pulse rinsing unit is arranged on the outside of the sensitive film on the surface of the ion sensor electrode. The core actuator of the pulse rinsing unit is a corrosion-resistant micro-nozzle. The corrosion-resistant micro-nozzle is aligned with the sensitive film on the surface of the ion sensor electrode in a ring array. The liquid inlet pipe of the corrosion-resistant micro-nozzle is connected to the impurity-free deionized water / process mother liquor that is matched with the reactor. A pulse control valve is configured on the liquid inlet pipe.

7. The online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to claim 1, characterized in that: The specific process for obtaining the first key ion concentration measurement result after the coating layer is removed from the ion sensor electrode surface is as follows: The corrosion-resistant micro-nozzle of the pulse rinsing unit sprays impurity-free deionized water or process mother liquor onto the sensitive membrane surface of the ion sensor electrode. The sensitive membrane on the ion sensor electrode surface is cleaned using preset pulse parameters. After cleaning is stopped, the membrane is left to stand for a preset time, and the first measurement of the key ion concentration is performed to obtain the first key ion concentration measurement result on the ion sensor electrode surface after the coating layer is removed.

8. The online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to claim 1, characterized in that: The specific process for determining whether the coating layer has completely detached from the ion sensor electrode surface is as follows: The first key ion concentration measurement results, manganese tetroxide precipitate mass, and backscattered light intensity signal corresponding to the intermediate slurry were obtained from the ion sensor and converted into a unified molar flow rate change rate. The apparent consumption rate of key ion concentration, net formation rate of manganese tetroxide precipitate, and formation rate of intermediate colloid were calculated. The synchronization deviation is calculated as the sum of the apparent consumption rate and the theoretical formation rate of the key ion concentration. Synchronization deviation = apparent consumption rate of key ion concentration - net formation rate of manganese tetroxide precipitate - formation rate of intermediate colloid. Set up a collection window and divide it into N sampling points. Obtain the synchronization deviation corresponding to the apparent consumption rate of the key ion concentration at each sampling point. If the synchronization deviation value of each sampling point is less than the synchronization deviation of the previous sampling point, it is determined that the capping layer has completely detached. Otherwise, it is determined that the capping layer has not completely detached.

9. The online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to claim 1, characterized in that: The specific process for secondary cleaning of the ion sensor electrode surface is as follows: If it is determined that the coating layer has not completely detached, the production line DCS control system increases the cleaning frequency of the pulse rinsing unit. Based on the original preset pulse rinsing frequency, it is adjusted upwards by gradient and the adjusted pulse rinsing unit is started to perform secondary pulse cleaning on the surface of the sensitive membrane of the ion sensor electrode.

10. The online monitoring of key ion concentrations during the synthesis of manganese tetroxide according to claim 1, characterized in that: The specific process of taking the first critical ion concentration measurement result after the coating layer is completely removed from the ion sensor electrode surface as the true critical ion concentration is as follows: If the determination result is that the capping layer has been completely removed, the first critical ion concentration measurement result detected by the ion sensor will be recorded as the current true critical ion concentration in the reactor.

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