A continuous impurity removal and precipitation method for an ionic rare earth candle filter device

Abstract

The present invention discloses a continuous impurity removal and precipitation method of an ionic rare earth candle filter device, which realizes efficient filtration and recovery of rare earth elements through six steps. First, a candle filter with automatic cleaning and backwashing functions is used for preliminary filtration to remove large particle impurities, and automatically transfer to the next step according to the preset filtration time or turbidity threshold. Secondly, the pH value of the leaching mother liquor is closed-loop controlled by a precise metering pump and a pH online monitoring system. Then, solid-liquid separation is carried out under a controllable working pressure difference to form a filter cake, and the filter cake is removed and discharged through the backwashing function. After the filter cake is collected, it is acid-dissolved and the rare earth elements are recovered. Finally, the turbidity and rare earth content of the filtered clear liquid are detected, and the filtration parameters are recorded and adjusted in real time through a data acquisition system to ensure product quality. The technical solution of the present invention realizes the full process automation control from the pretreatment of the leaching mother liquor to the solid-liquid separation and the shedding of the filter cake.

Description

Technical Field

[0001] The invention relates to the technical field of ionic rare earth ore extraction, in particular to a continuous impurity removal and precipitation method of an ionic rare earth candle filter device. Background Art

[0002] In the field of rare earth element extraction and separation, ionic rare earth ores have attracted much attention because they contain medium and heavy rare earth elements with high economic value. However, the existing extraction process has some obvious shortcomings.

[0003] First, the traditional extraction process relies on electrolyte solution elution and leaching mother liquor impurity removal. These processes usually use process pool precipitation concentration and plate and frame filter press to separate solids and liquids. Although this method has simple equipment and easy operation, it has the problem of low automation and intermittent operation, resulting in low production efficiency.

[0004] Secondly, the impurity removal and product precipitation processes in the prior art are all carried out in the process pool, which not only requires more land resources, but also further reduces the work efficiency of equipment and personnel due to the long precipitation and sedimentation time (usually 6 to 8 hours). In addition, the filtration efficiency of the plate and frame filter press is relatively low, and the moisture content of the filter cake is high, resulting in a poor on-site labor working environment, and also increasing the cost and difficulty of subsequent processing.

[0005] Furthermore, in the process of extracting rare earth elements, the existing technology often has problems of low efficiency and waste of resources in the treatment of rare earth leaching solution. For example, in the precipitation process, the loss of rare earth elements and the removal efficiency of impurities are not high, resulting in insufficient purity of the final product, which affects the market competitiveness of rare earth products.

[0006] Moreover, if the wastewater and waste residues generated during the rare earth extraction process are not properly handled, they will cause serious environmental pollution. Therefore, the development of a clean, efficient, simple and applicable solid-liquid separation method is of great significance for improving the overall performance and environmental sustainability of the rare earth extraction process.

[0007] In terms of continuous impurity removal and precipitation methods, some technologies have been used to try to improve the extraction efficiency and product quality of rare earths. For example, membrane separation technology is used to pretreat the leaching solution to improve the retention rate of rare earths and reduce the interference of impurities (see patent CN 102041389 A). In addition, by optimizing the preparation and use of precipitants, the precipitation efficiency and the purity of rare earth products can be improved (see patent CN 104962739 A).

[0008] Although existing technologies have made certain progress in the extraction of ionic rare earth ores, there are still some problems that need to be solved urgently.

[0009] For example, traditional intermittent operation cannot meet the needs of large-scale production. Secondly, during the leaching and precipitation process, rare earth loss is large, resulting in a low recovery rate. In addition, the existing technology uses a large amount of chemical reagents and water resources, generating a lot of waste and wastewater. Moreover, some operating steps have high energy consumption, which is not conducive to sustainable development. Summary of the invention

[0010] The purpose of the present invention is to provide a continuous impurity removal and precipitation method for an ionic rare earth candle filter device and a matching control system, thereby realizing the automation rate of the extraction process of ionic rare earth ores and improving its working efficiency.

[0011] Based on the first main aspect of the present invention, a continuous impurity removal and precipitation method of an ionic rare earth candle filter device is provided, comprising the following steps:

[0012] S1, using a high-efficiency candle filter to perform preliminary filtration on the ionic rare earth ore leaching mother liquor, the filter is designed with automatic cleaning and backwashing functions to remove large particle impurities; the preliminary filtration is set with a preset filtration time or turbidity threshold, and once the predetermined conditions are met, it automatically proceeds to the next step;

[0013] S2, adjusting the pH value of the leaching mother solution, and adjusting the amount of acid and alkali added in real time through a precise metering pump and a pH online monitoring system; the pH value adjustment process adopts a closed-loop control strategy, and the addition rate of the regulator is adjusted through a controller according to the comparison between the real-time monitored pH value and the preset value;

[0014] S3, under a controlled working pressure difference, inputting the pH-adjusted leaching mother liquor into a candle filter for solid-liquid separation to form a filter cake; the working pressure difference ranges from 0.6 to 2.5 MPa, and the working pressure difference is adjusted according to the density and filtration efficiency of the filter cake;

[0015] S4, when the filter cake reaches a certain thickness or the filtration resistance reaches a preset value, the back-blowing function of the candle filter is used to blow out the moisture in the filter cake with compressed air, and then back-blowing is performed to make the filter cake fall off and be discharged;

[0016] S5, collecting the filter cake through a filter cake collection system, and performing subsequent acid dissolution treatment and rare earth element recovery, wherein the filter cake collection system is equipped with an automatic weighing and conveying device to ensure accurate measurement and safe transfer of the filter cake;

[0017] S6, testing the turbidity and rare earth content of the filtered clear liquid to obtain test results; the test results are recorded in real time by a data acquisition system and compared with preset technical indicators. If there is a deviation, the system automatically adjusts the filtration parameters to ensure product quality.

[0018] This continuous impurity removal and precipitation method realizes the automation and continuous treatment of ionic rare earth ore leaching mother liquor by using high-efficiency candle filters. The automatic cleaning and backwashing functions significantly improve the filtration efficiency and reduce manual intervention. At the same time, the automatic transfer mechanism of the preset filtration time or turbidity threshold ensures the stability and reliability of the filtration process. The closed-loop control strategy of pH value further ensures the optimal conditions for rare earth element precipitation, thereby improving the extraction efficiency and product quality of rare earths.

[0019] As a further preferred embodiment, the candle filter includes one or more filter elements, each of which is wrapped with a filter cloth suitable for filtering rare earth elements.

[0020] As a further preferred embodiment, the filter cloth suitable for filtering rare earth elements is a PTFE coated filter cloth having a filtering accuracy of less than 1 micron, so that the turbidity value NTU of the filtered clear liquid is less than 1.

[0021] In the present invention, the filter element and filter cloth included in the candle filter, especially the application of PTFE coated filter cloth, provide high filtration accuracy for the filtration of rare earth elements. The filtration accuracy of less than 1 micron effectively reduces the turbidity of the clear liquid and ensures the quality of the clear liquid after filtration. This high-precision filter medium helps to improve the retention rate of rare earth elements, reduce the interference of impurities, and further improve the purity and market competitiveness of the product.

[0022] As a further preferred solution, the back-blowing function includes two stages: forward blowing and pulse back-blowing. The forward blowing uses compressed air of 0.2 to 0.4 MPa, and the pulse back-blowing uses compressed air of at least 0.2 MPa for 3 to 5 times. Through the two stages of forward blowing and pulse back-blowing, the moisture in the filter cake is effectively removed, and the filter cake shedding efficiency is optimized. This design not only improves the cleaning efficiency of the filtering equipment, but also reduces the re-attachment of the filter cake, prolongs the service life of the filter cloth, and reduces the maintenance cost.

[0023] Moreover, non-contact sensors monitor the thickness of the filter cake or the pressure drop of the filtration system in real time to ensure that backwashing is performed when the filter cake reaches the optimal shedding condition. This intelligent monitoring and control mechanism improves backwashing efficiency, reduces energy waste, and avoids damage to the filter cloth caused by excessive blowing.

[0024] As a further preferred solution, in step S3, the filter cake formation coefficient F is introduced fc It is used to characterize the density and filtration efficiency of the filter cake. The calculation formula is:

[0025]

[0026] Where V in is the volume of leaching mother liquor entering the filter per unit time, V outis the volume of clear liquid filtered per unit time, η is the filtration efficiency, ranging from 70% to 95%, and t is the filtration time.

[0027] In the formula, It indicates the volume of original leaching mother liquor corresponding to each unit volume of clear liquid, reflecting the concentration degree of liquid during the filtration process.

[0028] The filter cake formation coefficient is used to quantify the degree of filter cake formation and its effect on filtration efficiency. Middle molecule V in It represents the volume of leaching mother liquor entering the filter per unit time, and the denominator V out The ratio η represents the volume of clear liquid obtained per unit time. This ratio reflects the change in liquid volume before and after filtration. The efficiency η represents the ability of the filter cake to retain rare earth elements. (1-η) represents the proportion of the unretained liquid portion to the original volume. The index t represents the cumulative effect of the filtration process over time. As time goes by, the filter cake becomes thicker and the filtration efficiency increases, resulting in a decrease in the output of clear liquid.

[0029] (1-(1-η) in the denominator t It reflects the increase in the density of the filter cake as the filtration time increases. This value decreases with the increase of t, which means that the filter cake becomes denser and the filtration efficiency improves.

[0030] Because F fc Yes V in and V out The inverse of the ratio, so F fc The value of will increase with the density of the filter cake. fc The changes in the filtration process can be optimized in real time by adjusting the pressure difference, pH value, filtration time and other parameters to achieve the best filtration efficiency and rare earth element recovery rate.

[0031] As a further preferred solution, in step S3, the pressure difference adjustment coefficient D is defined as ac To adjust the working pressure difference in real time and optimize the solid-liquid separation efficiency, the calculation formula is:

[0032]

[0033] In the formula, ΔP set is the set working pressure difference, ΔP min and ΔP max are the minimum and maximum working pressure difference respectively, k is a constant related to the properties of the filter cake, with a value of 0.5-4, and Ffc is the filter cake formation coefficient.

[0034] Formula ΔP set The calculation first determines a pressure difference adjustment range, namely: ΔPmin to ΔP max between.

[0035] (1-e -k·F fc ) part is a random F fc The term that increases with the increase of k·F uses the characteristics of the exponential decay function. fc The increase of e -k·F fc Rapidly decreases, so that 1-e -k·Ffc This means that as the filter cake forms and thickens, the operating differential pressure needs to be increased to maintain the filtration efficiency. The coefficient k is used to adjust the sensitivity of the differential pressure adjustment, and its value depends on the nature of the filter cake and the specific requirements of the filtration system.

[0036] As a further preferred embodiment, the backflush function described in step S4 is implemented by:

[0037] S41, detecting the filter cake thickness or the filtration resistance, using a non-contact sensor to monitor the filter cake thickness or the pressure drop of the filtration system in real time;

[0038] S42, when the filter cake thickness reaches a preset value or the pressure drop exceeds a threshold, a backflush procedure is initiated, firstly by adjusting a valve to reduce the flow of the leaching mother liquor entering the filter to reduce further thickening of the filter cake;

[0039] S43, during the back-blowing process, at least two stages of compressed air are used, the first stage is to evenly blow dry the filter cake, and the second stage is pulse back-blowing to optimize the shedding efficiency of the filter cake.

[0040] In the above scheme, the steps to achieve the backflush function include reducing the leaching mother liquor flow rate and using multi-stage compressed air. These steps work together to optimize the filter cake shedding efficiency and filter cake drying effect. This meticulous control process helps to improve the operating efficiency of the filtration equipment and the quality of filter cake treatment.

[0041] As a further preferred embodiment, the filter cake collection system in step S5 at least comprises

[0042] A closed filter cake storage container equipped with temperature and humidity control devices to prevent physical or chemical changes in the filter cake during storage;

[0043] An automatic conveying system that automatically adjusts the conveying speed according to the weight and volume of the filter cake to ensure uniform conveying of the filter cake;

[0044] An integrated filter cake analysis module that automates sample collection and preliminary compositional analysis during the filter cake collection process to assess the rare earth element content of the filter cake.

[0045] The innovative design of the filter cake collection system includes a closed storage container, an automatic conveying system, and an integrated analysis module. The above design not only ensures the safe collection and transportation of the filter cake, but also realizes the real-time monitoring of the filter cake composition, providing accurate data support for the recovery of rare earth elements.

[0046] As a further preferred embodiment, the turbidity and rare earth content detection of the filtered clear liquid in step S6 includes:

[0047] S61, using spectral analysis technology to quantitatively analyze the rare earth elements in the clear solution to obtain more accurate rare earth content data;

[0048] S62, based on the spectral analysis results, uses intelligent algorithms to predict and adjust the parameters of the subsequent filtration process, such as pH value, working pressure difference and backwash intensity, to optimize the filtration efficiency and the recovery rate of rare earth elements;

[0049] S63, establish a feedback control system, when it is detected that the rare earth content in the clear liquid exceeds the preset limit, automatically start the clear liquid circulation filtration program until the technical index requirements are met.

[0050] The above steps provide a clear liquid detection and feedback control method, using spectral analysis technology to perform quantitative analysis of rare earth elements and automatically adjust the filtration parameters based on the results. This intelligent control strategy ensures the stability of the clear liquid quality and further optimizes the recovery efficiency of rare earth elements through a cyclic filtration program.

[0051] According to a second main aspect of the present invention, a control system for implementing the above method is provided, the system at least comprising:

[0052] Filter module: includes candle filter body and its automatic cleaning and backwashing functions;

[0053] pH adjustment module: consists of a precise metering pump, a pH sensor and a closed-loop controller;

[0054] Pressure difference control module: including pressure sensor, regulating valve and adaptive algorithm controller;

[0055] Backflush control module: It consists of a compressed air supply system, an intelligent control system and a pulse backflush mechanism;

[0056] Filter cake processing module: including filter cake collection, weighing, transportation, humidity control and analysis system;

[0057] Clear liquid detection module: including turbidity meter, rare earth content analysis instrument and data acquisition system;

[0058] Data recording and analysis module: used to store and analyze data during the filtering process and perform statistical process control;

[0059] Intelligent control center: Integrates the control algorithms of all modules and provides a user interface for system monitoring and operation;

[0060] Feedback adjustment module: automatically adjusts filtering parameters according to the detection results to ensure filtering quality.

[0061] Compared with the prior art, the technical solution of the present invention realizes the full process automation control from pretreatment of leaching mother liquor to solid-liquid separation and filter cake shedding. By accurately controlling the pH value and working pressure difference, and adopting high-efficiency filter media and optimized backflushing function, this method not only improves the extraction efficiency of rare earth elements, but also ensures the high purity of the clear liquid after filtration and the effective shedding of the filter cake. These technical effects work together to improve the production efficiency, product quality and environmental sustainability of the entire rare earth extraction process.

[0062] In addition, the method reduces the use of chemical reagents and water resources, reduces the generation of waste and wastewater, and meets the requirements of green chemistry and sustainable development. Automated and continuous operation reduces energy consumption and labor costs, and improves the economic efficiency of the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention 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 only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0064] Figure 1 A working diagram of an embodiment of the present invention is shown;

[0065] Figure 2 A schematic diagram of the control system structure of an embodiment of the present invention is shown.

[0066] Figure 3 A schematic diagram of a candle filter device used in one embodiment of the present invention is shown. DETAILED DESCRIPTION

[0067] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings so that the purpose, features and advantages of the present invention can be more clearly understood. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0068] In the following description, certain specific details are set forth for the purpose of illustrating the various disclosed embodiments to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of these specific details. In other cases, well-known devices, structures, and techniques associated with the present application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0069] References throughout the specification to "one embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in one embodiment" or "in an embodiment" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any manner in one or more embodiments.

[0070] like Figure 1 As shown, in this embodiment, the continuous impurity removal and precipitation method of the ionic rare earth candle filter device adopts the following method: Figure 3 The device shown comprises the following steps:

[0071] S1, using a high-efficiency candle filter to perform preliminary filtration on the ionic rare earth ore leaching mother liquor, the filter is designed with automatic cleaning and backwashing functions to remove large particle impurities; the preliminary filtration is set with a preset filtration time or turbidity threshold, and once the predetermined conditions are met, it automatically proceeds to the next step;

[0072] In step S1, the automation of the preliminary filtration is achieved through a high-efficiency candle filter with automatic cleaning and backwashing functions. This design significantly reduces manual intervention while ensuring the continuity and stability of the filtration process. The automatic cleaning function of the filter is triggered by a timer or turbidity sensor and is automatically executed at a preset time interval or turbidity level, effectively removing large particles of impurities on the filter cloth and preventing clogging of the filter holes.

[0073] In the preliminary filtration stage, the system allows the operator to preset the filtration time or turbidity threshold according to the properties of the leaching mother liquor and the required filtration accuracy. Once these preset conditions are met, the control system will automatically switch to the next step without manual monitoring. This intelligent monitoring mechanism not only improves the filtration efficiency, but also ensures the quality of the filtrate, providing consistent raw material quality for the subsequent pH adjustment and solid-liquid separation steps.

[0074] In order to further improve the filtration efficiency, the filter's operating parameters such as flow rate and pressure are adjusted and controlled. The control of flow rate directly affects the filtration speed and the turbidity of the filtrate, while the proper adjustment of pressure can optimize the filtration effect and avoid excessive compression of the filter cake leading to a decrease in filtration efficiency. By real-time monitoring and adjusting these parameters, it can be ensured that the filtrate reaches the expected turbidity standard while maintaining a high filtration speed, laying a solid foundation for the entire continuous impurity removal and sedimentation process.

[0075] S2, adjusting the pH value of the leaching mother solution, and adjusting the amount of acid and alkali added in real time through a precise metering pump and a pH online monitoring system; the pH value adjustment process adopts a closed-loop control strategy, and the addition rate of the regulator is adjusted through a controller according to the comparison between the real-time monitored pH value and the preset value;

[0076] In step S2, the pH value of the leaching mother liquor is adjusted by a high-precision pH online monitoring system. The system adopts a pH adjustment module, uses a pH sensor to measure the pH value of the leaching mother liquor in real time, and transmits the data to the central control system. The operator presets the target value according to the optimal pH range for rare earth element precipitation, and the control system automatically adjusts the amount of acid-base regulator added through a closed-loop control strategy based on the deviation between the real-time data and the preset target value.

[0077] The precision metering pump is the core component of the pH adjustment module. It dynamically adjusts its operation according to the instructions of the control system to accurately add the required acid-base regulator to the mother leachate. The design of this pump ensures uniform mixing and accurate dosing of the regulator even under continuous flow conditions. By adjusting the operating speed of the metering pump in real time, it can quickly respond to changes in pH value and ensure that the pH value of the mother leachate is stable within the optimal range.

[0078] The optimization of the closed-loop control system is achieved through advanced algorithms and control logic, taking into account the dynamic characteristics of pH changes and the system response time. The control system is able to predict and compensate for short-term fluctuations in pH, reducing the over- or under-addition of regulators. In addition, the system is able to learn changes in operating conditions and continuously optimize control parameters through machine learning algorithms to improve the accuracy and efficiency of pH control. This intelligent control strategy not only improves the efficiency of rare earth element precipitation, but also reduces the consumption of chemical reagents and reduces production costs.

[0079] The above advanced algorithms and control logic include:

[0080] Predictive Control, this algorithm predicts the future dynamic behavior of the system by building a mathematical model of the process. Based on the historical data of the pH value of the leaching mother liquor and the current measured value, the predictive control algorithm can predict the trend of pH value changes in the future and calculate the optimal amount of regulator to ensure that the pH value is stable within the preset target range. The advantage of this algorithm is that it takes into account the future behavior of the system, which can reduce the amount of regulator and improve control accuracy.

[0081] Adaptive Control and machine learning algorithms that automatically adjust control parameters based on changes in system performance over time. Adaptive control algorithms can identify uncertainties and nonlinearities in the pH control process and adjust control strategies in real time to accommodate these changes. Machine learning algorithms, such as neural networks or support vector machines, can learn the best strategy for pH control from historical operating data and predict the best timing and amount of regulator addition. In this way, the control system can continuously optimize itself, improve the stability and efficiency of pH control, reduce the use of chemical reagents, and reduce production costs.

[0082] S3, under a controlled working pressure difference, inputting the pH-adjusted leaching mother liquor into a candle filter for solid-liquid separation to form a filter cake; the working pressure difference ranges from 0.6 to 2.5 MPa, and the working pressure difference is adjusted according to the density and filtration efficiency of the filter cake;

[0083] Step S3 focuses on the solid-liquid separation process of the leached mother liquor after adjusting the pH value. This step is carried out under a controlled working pressure difference, which is set in the range of 0.6 to 2.5 MPa, ensuring the efficiency and stability of the filtration process. By precisely controlling the pressure difference, the candle filter can effectively separate solid impurities from the liquid to form a filter cake. The key to this step is to maintain an appropriate pressure difference, which can ensure the filtration efficiency without causing excessive compression of the filter cake and affecting its subsequent processing.

[0084] In step S3, the dynamic adjustment of the working pressure difference is achieved through the pressure difference control module. The module consists of a pressure sensor, a regulating valve and an adaptive algorithm controller. The pressure sensor monitors the pressure difference during the filtration process in real time and feeds the data back to the adaptive algorithm controller. The controller automatically adjusts the opening of the regulating valve according to the density of the filter cake and the changes in filtration efficiency to achieve precise control of the working pressure difference. This dynamic adjustment strategy ensures that the filtration process remains in the best state throughout the operation cycle.

[0085] The formation of the filter cake and the monitoring of its characteristics are another important aspect of the S3 step. As the filtration process proceeds, the filter cake gradually thickens, and its density and filtration resistance will change accordingly. By monitoring the thickness of the filter cake and the pressure drop of the filtration system, the characteristics of the filter cake can be evaluated, and the operating pressure difference and filtration parameters can be adjusted based on this information. This real-time monitoring and adjustment mechanism helps to optimize the filtration efficiency, improve the quality of the filter cake, and provide a good basis for the subsequent filter cake treatment and rare earth element recovery steps.

[0086] S4, when the filter cake reaches a certain thickness or the filtration resistance reaches a preset value, the back-blowing function of the candle filter is used to blow out the moisture in the filter cake with compressed air, and then back-blowing is performed to make the filter cake fall off and be discharged;

[0087] Step S4 starts when the filter cake reaches a certain thickness or the filtration resistance reaches a preset value, at which point the system automatically triggers the backflush procedure. First, the non-contact sensor monitors the thickness of the filter cake and the pressure drop of the filtration system in real time, which are crucial for determining the best time for backflush. Once the filter cake thickness or pressure drop reaches the predetermined conditions, the system will reduce the flow of leaching mother liquor entering the filter, which helps control the further thickening of the filter cake and prepares for backflush.

[0088] During the backflush process, the system uses compressed air to treat the filter cake. The first stage uses compressed air to evenly dry the moisture in the filter cake, which helps reduce the humidity of the filter cake and makes it easier to fall off. The system then enters the second stage, pulsed backflush, which uses intermittent high-pressure air pulses to disturb the filter cake and make it fall off the filter cloth surface, thereby achieving efficient removal.

[0089] After the pulse backflush, the filter cake begins to fall off the filter cloth. At this point, the system design ensures that the filter cake can be discharged smoothly to avoid accumulation inside the filter. The efficiency of the filter cake discharge directly affects the continuous operation ability of the entire filtration system and the start of the next filtration cycle. After the filter cake is discharged, it can be collected and processed subsequently, such as acid dissolution and rare earth element recovery, while the filter is ready to receive a new batch of leaching mother liquor and start a new round of filtration cycle. This automated and efficient backflush and discharge mechanism significantly improves the performance and productivity of the entire filtration process.

[0090] S5, collecting the filter cake through a filter cake collection system, and performing subsequent acid dissolution treatment and rare earth element recovery, wherein the filter cake collection system is equipped with an automatic weighing and conveying device to ensure accurate measurement and safe transfer of the filter cake;

[0091] After the filter cake falls off in step S4, step S5 involves the collection and transfer process of the filter cake. The filter cake collection system is designed with a special collection container, which is connected to the discharge port of the candle filter to ensure that the filter cake can be collected safely and accurately. The collection system is equipped with an automatic weighing function, which can monitor the weight of the filter cake in real time to ensure the accuracy and repeatability of the collection process. In addition, the design of the collection container takes into account the ease of operation and the convenience of maintenance.

[0092] After the filter cake is collected, the automatic conveying device transfers it from the collection container to the storage or processing area. The conveying system can adjust the conveying speed and force according to the physical characteristics of the filter cake, such as humidity and viscosity, to ensure the integrity and uniformity of the filter cake during the conveying process. The storage container is equipped with a temperature and humidity control device to prevent the filter cake from undergoing physical or chemical changes during storage, which is essential to maintaining the quality of the filter cake and the efficiency of subsequent processing.

[0093] While the filter cake is being collected and transported, the integrated filter cake analysis module performs a preliminary composition analysis on the filter cake to assess its rare earth element content. This analysis result is crucial for optimizing the subsequent acid dissolution treatment and rare earth element recovery process. The automated analysis system can reduce human errors and improve the accuracy and repeatability of the analysis. Based on the analysis results, the operator can adjust the process parameters, such as the concentration, time and temperature of the acid dissolution treatment, to maximize the recovery rate of rare earth elements and minimize resource waste.

[0094] S6, testing the turbidity and rare earth content of the filtered clear liquid to obtain test results; the test results are recorded in real time by a data acquisition system and compared with preset technical indicators. If there is a deviation, the system automatically adjusts the filtration parameters to ensure product quality.

[0095] Step S6 focuses on the quality inspection of the clear liquid after filtration. The turbidity of the clear liquid is measured using an advanced turbidity meter to evaluate the filtration efficiency. The turbidity meter is able to provide continuous real-time data to ensure that the clear liquid meets the required transparency standards. In addition, rare earth content analysis instruments, such as inductively coupled plasma mass spectrometer (ICP-MS) or atomic absorption spectrometer (AAS), are used to quantitatively analyze the rare earth element concentration in the clear liquid to ensure that it meets the product quality requirements.

[0096] The test results are recorded in real time through the data acquisition system. These data are not only used for immediate quality control, but also stored in the database for further analysis. The data recording and analysis module uses statistical process control (SPC) technology to analyze the collected data to identify trends and potential problems in the filtration process. Through this analysis, quality problems can be predicted and prevented, and continuous process improvement can be achieved.

[0097] Step S6 also includes a feedback control system that automatically adjusts the filtration parameters based on the results of the clear liquid test. For example, if the rare earth content exceeds the preset limit, the system will automatically adjust the pH value, working pressure difference or backwash intensity to optimize the filtration effect. In some cases, if the clear liquid quality does not meet the standard, the system will start a circulating filtration program and reintroduce the clear liquid into the filtration system for reprocessing until it meets the technical indicators. This intelligent feedback adjustment mechanism ensures the consistency and reliability of product quality.

[0098] The control system of the present invention is composed as follows: Figure 2 As shown, the system at least includes:

[0099] Filter module: includes candle filter body and its automatic cleaning and backwashing functions;

[0100] pH adjustment module: consists of a precise metering pump, a pH sensor and a closed-loop controller;

[0101] Pressure difference control module: including pressure sensor, regulating valve and adaptive algorithm controller;

[0102] Backflush control module: It consists of a compressed air supply system, an intelligent control system and a pulse backflush mechanism;

[0103] Filter cake processing module: including filter cake collection, weighing, transportation, humidity control and analysis system;

[0104] Clear liquid detection module: including turbidity meter, rare earth content analysis instrument and data acquisition system;

[0105] Data recording and analysis module: used to store and analyze data during the filtering process and perform statistical process control;

[0106] Intelligent control center: Integrates the control algorithms of all modules and provides a user interface for system monitoring and operation;

[0107] Feedback adjustment module: automatically adjusts filtering parameters according to the detection results to ensure filtering quality.

[0108] The filter module is the core part of the present invention. The candle filter body is designed to efficiently treat the ionic rare earth ore leaching mother liquor. The filter is equipped with automatic cleaning and backwashing functions to ensure the continuous cleaning of the filter cloth during the filtration process, prevent clogging, and maintain filtration efficiency. The automatic control system adjusts the frequency and intensity of cleaning and backwashing according to real-time feedback data.

[0109] The pH adjustment module consists of a precision metering pump, a pH sensor and a closed-loop controller to achieve precise control of the pH value of the leaching mother solution. The pH sensor monitors the pH value of the solution in real time and transmits the data to the controller. The controller automatically adjusts the operation of the metering pump to add the appropriate amount of acid-base regulator based on the comparison of the preset pH value with the real-time data.

[0110] The differential pressure control module uses a pressure sensor to monitor the differential pressure during the filtration process and maintains the optimal working pressure by adjusting the valve and adaptive algorithm controller. The adaptive algorithm dynamically adjusts the working differential pressure according to the density of the filter cake and the filtration efficiency to ensure the optimization of solid-liquid separation efficiency.

[0111] The back-blowing control module includes a compressed air supply system, an intelligent control system and a pulse back-blowing mechanism. When the filter cake reaches a certain thickness or the filtration resistance reaches a preset value, the intelligent control system starts the back-blowing program, evenly blows the filter cake dry with compressed air and performs pulse back-blowing to effectively remove the filter cake.

[0112] The cake handling module is responsible for the collection, weighing, conveying, humidity control and analysis of the filter cake. The collection system automatically weighs the filter cake to ensure accurate measurement. The conveying system automatically adjusts the speed according to the weight and volume of the filter cake to ensure uniform conveying. The humidity control device maintains the temperature and humidity in the filter cake storage container to prevent physical or chemical changes.

[0113] The clear liquid detection module includes a turbidity meter, rare earth content analyzer and data acquisition system to perform real-time detection of the filtered clear liquid. The data recording and analysis module is responsible for storing and analyzing all key data in the filtration process and performing statistical process control to identify trends and potential problems.

[0114] As the brain of the system, the intelligent control center integrates the control algorithms of all modules and provides a user interface for system monitoring and operation. The feedback adjustment module automatically adjusts the filtration parameters such as pH value, working pressure difference and backwash intensity according to the clear liquid test results to ensure that the filtration quality meets the preset technical indicators.

[0115] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A continuous impurity removal and precipitation method for an ionic rare earth candle filter device, characterized in that: The method comprises the following steps: S1, using a high-efficiency candle filter to perform preliminary filtration on the ionic rare earth ore leaching mother liquor, the filter is designed with automatic cleaning and backwashing functions to remove large particle impurities; the preliminary filtration is set with a preset filtration time or turbidity threshold, and once the predetermined conditions are met, it automatically proceeds to the next step; S2, adjusting the pH value of the leaching mother solution, and adjusting the amount of acid and alkali added in real time through a precise metering pump and a pH online monitoring system; the pH value adjustment process adopts a closed-loop control strategy, and the addition rate of the regulator is adjusted through a controller according to the comparison between the real-time monitored pH value and the preset value; S3, under a controlled working pressure difference, inputting the pH-adjusted leaching mother liquor into a candle filter for solid-liquid separation to form a filter cake; the working pressure difference ranges from 0.6 to 2.5 MPa, and the working pressure difference is adjusted according to the density and filtration efficiency of the filter cake; S4, when the filter cake reaches a certain thickness or the filtration resistance reaches a preset value, the back-blowing function of the candle filter is used to blow out the moisture in the filter cake with compressed air, and then back-blowing is performed to make the filter cake fall off and be discharged; S5, collecting the filter cake through a filter cake collection system, and performing subsequent acid dissolution treatment and rare earth element recovery, wherein the filter cake collection system is equipped with an automatic weighing and conveying device to ensure accurate measurement and safe transfer of the filter cake; S6, testing the turbidity and rare earth content of the filtered clear liquid to obtain test results; the test results are recorded in real time by a data acquisition system and compared with preset technical indicators. If there is a deviation, the system automatically adjusts the filtration parameters to ensure product quality.

2. The continuous impurity removal and precipitation method of the ionic rare earth candle filter equipment according to claim 1 is characterized in that: The candle filter comprises one or more filter elements, each of which is wrapped with a filter cloth suitable for filtering rare earth elements.

3. The continuous impurity removal and precipitation method of the ionic rare earth candle filter equipment according to claim 2 is characterized in that: The filter cloth suitable for filtering rare earth elements is a PTFE-coated filter cloth, which has a filtering accuracy of less than 1 micron, so that the turbidity value NTU of the filtered clear liquid is less than 1.

4. The continuous impurity removal and precipitation method of the ionic rare earth candle filter equipment according to claim 1, characterized in that: The back-blowing function includes two stages: forward blowing and pulse back-blowing. The forward blowing uses compressed air of 0.2 to 0.4 MPa, and the pulse back-blowing uses compressed air of at least 0.2 MPa for 3 to 5 times.

5. The continuous impurity removal and precipitation method of the ionic rare earth candle filter equipment according to claim 1, characterized in that: In step S3, the filter cake formation coefficient F is introduced fc It is used to characterize the density and filtration efficiency of the filter cake. The calculation formula is: Where V in is the volume of leaching mother liquor entering the filter per unit time, in m 3 / h; V out It is the volume of clear liquid filtered per unit time, in m 3 / h; η is the filtration efficiency, ranging from 70% to 95%; t is the filtering time in hours.

6. The continuous impurity removal and precipitation method of the ionic rare earth candle filter equipment according to claim 5, characterized in that: In step S3, the pressure difference adjustment coefficient D is defined ac To adjust the working pressure difference in real time and optimize the solid-liquid separation efficiency, the calculation formula is: In the formula, ΔP set is the set working pressure difference, ΔP min and ΔP max They are the minimum and maximum values ​​of the working pressure difference, both in MPa; k is a constant related to the properties of the filter cake, with a value of 0.5-4, F fc is the filter cake formation coefficient.

7. The continuous impurity removal and precipitation method of the ionic rare earth candle filter equipment according to claim 1, characterized in that: The implementation of the backflush function described in step S4 includes: S41, detecting the filter cake thickness or the filtration resistance, using a non-contact sensor to monitor the filter cake thickness or the pressure drop of the filtration system in real time; S42, when the filter cake thickness reaches a preset value or the pressure drop exceeds a threshold, a backflush procedure is initiated, firstly by adjusting a valve to reduce the flow of the leaching mother liquor entering the filter to reduce further thickening of the filter cake; S43, during the back-blowing process, at least two stages of compressed air are used, the first stage is to evenly blow dry the filter cake, and the second stage is pulse back-blowing to optimize the shedding efficiency of the filter cake.

8. The continuous impurity removal and precipitation method of the ionic rare earth candle filter equipment according to claim 1, characterized in that: The filter cake collection system described in step S5 at least comprises A closed filter cake storage container equipped with temperature and humidity control devices to prevent physical or chemical changes in the filter cake during storage; An automatic conveying system that automatically adjusts the conveying speed according to the weight and volume of the filter cake to ensure uniform conveying of the filter cake; An integrated filter cake analysis module that automates sample collection and preliminary compositional analysis during the filter cake collection process to assess the rare earth element content of the filter cake.

9. The continuous impurity removal and precipitation method of the ionic rare earth candle filter equipment according to claim 1, characterized in that: The step S6 of testing the turbidity and rare earth content of the filtered clear liquid includes: S61, using spectral analysis technology to quantitatively analyze the rare earth elements in the clear solution to obtain more accurate rare earth content data; S62, based on the spectral analysis results, uses intelligent algorithms to predict and adjust the parameters of the subsequent filtration process, including pH value, working pressure difference and backwash intensity, to optimize the filtration efficiency and the recovery rate of rare earth elements; S63, establish a feedback control system, when it is detected that the rare earth content in the clear liquid exceeds the preset limit, automatically start the clear liquid circulation filtration program until the technical index requirements are met.

10. A control system for implementing the method according to any one of claims 1 to 9, characterized in that: The system includes at least: Filter module: includes candle filter body and its automatic cleaning and backwashing functions; pH adjustment module: consists of a precise metering pump, a pH sensor and a closed-loop controller; Pressure difference control module: including pressure sensor, regulating valve and adaptive algorithm controller; Backflush control module: It consists of a compressed air supply system, an intelligent control system and a pulse backflush mechanism; Filter cake processing module: including filter cake collection, weighing, transportation, humidity control and analysis system; Clear liquid detection module: including turbidity meter, rare earth content analysis instrument and data acquisition system; Data recording and analysis module: used to store and analyze data during the filtering process and perform statistical process control; Intelligent control center: Integrates the control algorithms of all modules and provides a user interface for system monitoring and operation; Feedback adjustment module: automatically adjusts filtering parameters according to the detection results to ensure filtering quality.

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