A system for grading and recycling rare earth resources in radioactive tailings

Abstract

The application discloses a rare earth resource grading recycling system in radioactive tailings, and relates to the technical field of hydrometallurgy. The system comprises a gamma spectrometer, which is used for obtaining initial gamma spectrum information of radioactive tailings and on-line monitoring of activity ratio of characteristic gamma rays of uranium series or thorium series in the leaching process; a leaching tank, which is used for containing tailing slurry and carrying out leaching; a controller, which is connected with the gamma spectrometer and the leaching tank respectively; and a storage device, which is connected with the controller and is used for storing process archives. The application carries out dynamic regulation and control on the leaching process in stages according to the activity ratio change trend. After selective preferential dissolution of high-activity minerals, intensified leaching is carried out on low-activity minerals, so that the total rare earth recovery rate is improved, and the co-leaching of radioactive impurities such as uranium and thorium is effectively inhibited.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically a graded recycling system for rare earth resources in radioactive tailings. Background Technology

[0002] Radioactive tailings contain considerable rare earth resources, but existing acid or alkaline leaching processes mostly use fixed parameters to treat the entire batch of tailings uniformly. Due to varying degrees of weathering and irradiation damage during storage, the lattice defect density of rare earth minerals in the tailings varies significantly, directly determining their reactivity: those with higher defect densities are more easily leached under mild conditions, while those with lower defect densities require stronger leaching. Under fixed parameters, if the parameters are too mild, the leaching of low-activity minerals is insufficient, resulting in low rare earth recovery; if the parameters are too strong, the high-activity minerals are excessively broken down, leading to a large amount of co-dissolution of radioactive impurities such as uranium and thorium, increasing the difficulty of subsequent separation and the burden of waste liquid treatment.

[0003] Some existing technologies measure lattice defect density offline using transmission electron microscopy or X-ray diffraction, and then manually adjust leaching parameters. However, this method has a long analysis cycle, high cost, and cannot be matched with continuous processing flow, resulting in a significant lag in process adjustment.

[0004] On the other hand, uranium and thorium nuclides naturally present in radioactive tailings release characteristic gamma rays during decay, and gamma spectroscopy analysis is a mature application in nuclear geophysics. However, current technologies have not yet established a correlation between the activity ratio of characteristic gamma rays from uranium or thorium series nuclides and the lattice defect density of rare earth minerals, let alone used them for online monitoring and leaching classification control. Existing processes fail to utilize the radioactive nuclides in the tailings themselves as natural tracer sources, thus missing a technical approach to real-time inversion of mineral reactivity through non-destructive online detection.

[0005] Therefore, there is an urgent need for a system that can sense the reactivity of tailings minerals online and implement graded leaching control accordingly, in order to improve rare earth recovery rate, suppress co-leaching of radioactive impurities, and reduce process commissioning and operating costs. Summary of the Invention

[0006] The purpose of this application is to provide a graded recycling system for rare earth resources in radioactive tailings, in order to solve the problems in the prior art, such as poor leaching selectivity, large fluctuations in rare earth recovery rate, and high co-leaching rate of radioactive impurities caused by the density difference of mineral lattice defects in tailings.

[0007] To achieve the above objectives, this application adopts the following technical solution: A system for graded recovery and utilization of rare earth resources in radioactive tailings includes a gamma spectrometer, a leaching tank, a controller, and a storage device. The gamma spectrometer is used to acquire initial gamma spectrum information of the radioactive tailings and to monitor the activity ratio of characteristic gamma rays of uranium-series or thorium-series rays online during the leaching process. The leaching tank is used to contain the tailings slurry and perform leaching. The controller is connected to both the gamma spectrometer and the leaching tank. The storage device is connected to the controller and is used to store process records.

[0008] The controller is used for: The initial gamma spectrum information acquired by the gamma spectrometer is received, and an initial mapping relationship between the characteristic gamma ray activity ratio of uranium-series or thorium-series minerals and the lattice defect density of each rare earth mineral is established based on the information, wherein the lattice defect density is the surface density or the volume density.

[0009] It should be noted that this mapping relationship is not based on rigorous nuclear physics theoretical derivation, but rather on engineering empirical rules obtained from experimental calibration of standard mineral samples of tailings from the same source. For radioactive tailings from a specific source, there is a stable statistical correspondence between the activity ratio of characteristic gamma rays in their uranium- or thorium-series decay chains and the lattice defect density of rare earth minerals. This correspondence varies depending on the source and storage conditions of the tailings, and therefore needs to be determined through pre-calibration. This calibration process is a routine experimental method for those skilled in the art and can be implemented without relying on imperfect theoretical models.

[0010] During the leaching process, the activity ratio is received by the online monitoring of the gamma spectrometer. Based on the online monitoring value of the activity ratio, a low-intensity leaching strategy is controlled to selectively dissolve target minerals with high reactivity during the activity ratio rising phase, and a high-intensity leaching strategy is controlled to dissolve target minerals with low reactivity during the activity ratio falling phase.

[0011] When the rate of change of the activity ratio decreases from a positive value to below a preset threshold, the leaching of the current target mineral is determined to be complete, triggering an adjustment of the leaching conditions or stopping the leaching of the current stage.

[0012] The initial γ-ray spectrum information, activity ratio change sequence, and leaching efficiency at each stage are recorded in the storage device as a process file. The initial mapping relationship is corrected based on the process file to obtain the optimized mapping relationship.

[0013] In a preferred embodiment, the low-intensity leaching strategy includes a leaching agent concentration parameter and a leaching duration parameter. The controller also acquires the real-time solids mass fraction of the slurry in the leaching tank; when the solids mass fraction is higher than a first mass fraction threshold, the leaching agent concentration parameter is reduced. When the solid mass fraction is lower than the second mass fraction threshold, the leaching agent concentration parameter is increased; When the solid mass fraction is higher than the third mass fraction threshold, the leaching time parameter is extended.

[0014] In another preferred embodiment, the high-intensity leaching strategy includes a heating rate parameter and a stirring speed parameter. The controller also acquires real-time viscosity data and bubble generation rate of the slurry in the leaching tank. When the viscosity is higher than a first viscosity threshold, the stirring speed parameter is increased; when the viscosity is lower than a second viscosity threshold, the stirring speed parameter is decreased; and when the bubble generation rate is higher than a preset rate threshold, the heating rate parameter is decreased.

[0015] Furthermore, the controller also acquires ambient temperature fluctuation data and humidity data outside the leaching tank. When the ambient temperature fluctuation exceeds a first fluctuation threshold and the humidity exceeds a preset humidity threshold, the heating belt anti-condensation protection is activated. The controller also assesses the stability risk of the current leaching temperature control based on the ambient temperature fluctuation. If the risk level is high, the proportional gain of the heating system is reduced; if the risk level is low, the proportional gain is increased.

[0016] In another preferred embodiment, the controller further acquires the initial gamma-ray spectrum information and X-ray fluorescence spectrum information of the current batch of radioactive tailings. The net count rate of uranium-series or thorium-series characteristic peaks is extracted from the initial gamma-ray spectrum information as a first set of reference features, and the characteristic X-ray fluorescence intensity of rare earth elements is extracted from the X-ray fluorescence spectrum information as a second set of reference features. The first set of reference features and the second set of reference features are combined to form a comprehensive feature vector for the current batch. The comprehensive feature vectors of historical batches with the same or similar origin to the current batch of tailings are queried from the process archive in the storage device. Feature similarity is calculated, and a preset threshold for the activity ratio change rate is matched and initialized from the process archive based on the feature similarity. The comprehensive feature vector of the current batch, the threshold value, and the actual leaching effect are recorded in the process archive for use in threshold initialization of subsequent batches.

[0017] In another preferred embodiment, the controller further acquires the redox potential and pH value of the slurry in the leaching tank, combines the activity ratio, redox potential, and pH value into a three-dimensional state vector, and compares the three-dimensional state vector with a pre-constructed standard curve library for leaching high-defect minerals in real time. When the comparison result is higher than a first comparison threshold, the execution time of the current leaching stage is extended; when the comparison result is lower than a second comparison threshold, the current stage is terminated early and the next leaching stage is started. If the change direction of the activity ratio is opposite to the change direction of the redox potential and the deviation exceeds a preset allowable range, leaching is paused and sampling verification is performed.

[0018] Preferably, the controller also continuously records the change in activity ratio over time and determines whether the change is accelerating or decelerating. When the rate of increase in activity ratio begins to slow down continuously, that is, when the increase in activity ratio per unit time gradually decreases and turns into a negative increase, the transition from a low-intensity leaching strategy to a high-intensity leaching strategy is initiated ahead of schedule. During the transition, the concentration of the leaching agent and the leaching temperature are gradually increased, with the increase set in stages according to the rate of decrease in activity ratio. If the actual value of activity ratio continues to rise after the transition is initiated and exceeds the predicted maximum point by a certain range, the low-intensity leaching stage is automatically extended, and the activity ratio change record for this batch is stored as a new feature in the process archive.

[0019] In a preferred embodiment, the system further includes an X-ray fluorescence analysis probe, positioned outside the leaching tank and at the same location as the gamma spectrometer, for online monitoring of the X-ray fluorescence intensity of at least one characteristic rare earth element in the leachate. The controller aligns the X-ray fluorescence intensity change curve with the activity ratio change curve on the time axis, calculating the correlation between the relative enrichment degree of each rare earth element and the activity ratio during the leaching process. When the relative enrichment degree of a certain rare earth element reaches its peak during the activity ratio increase phase and then begins to decline, while the activity ratio is still increasing, a complexing agent is added to the leaching tank or the pH value is adjusted. When the rate of change of the activity ratio decreases below a preset minimum rate while the X-ray fluorescence intensity of the characteristic rare earth element is still rapidly increasing, leaching is preferentially determined based on the X-ray fluorescence intensity, and the preset minimum rate is automatically lowered.

[0020] In another preferred embodiment, the controller also compares the actual activity ratio change curve measured during the current batch leaching process with the standard change curve predicted by the initial mapping relationship established for that batch, calculating the difference sequence between the two curves. When the fluctuation amplitude of the difference sequence remains within a preset stable range for multiple consecutive sampling periods, preparation for terminating leaching begins. During the termination preparation phase, the autocorrelation degree of the difference sequence is calculated. When the autocorrelation degree changes from positive to negative and exceeds a preset limit, the high-intensity leaching strategy is stopped. The difference sequence characteristics at the time of termination are recorded in the process file for use in correcting the expected change curve of the next batch of tailings from the same source.

[0021] In another preferred embodiment, the controller also merges the initial gamma spectrum data, the activity ratio variation curve, the leaching parameters used in each stage, and the final rare earth recovery rate of each batch of tailings into a single batch sample and stores it in the process archive. When the initial gamma spectrum of a new batch of tailings is more similar to the gamma spectrum of a historical batch in the process archive than a preset standard, the leaching strategy parameter sequence of that historical batch is directly used as the initial leaching scheme for the new batch. During the leaching process of the new batch, the difference between the actual activity ratio variation curve and the historical batch curve is compared in real time. When the accumulated difference exceeds a preset allowable range, online correction is initiated: using the historical batch curve as a target, the current leaching agent concentration and temperature are adjusted so that the actual activity ratio variation curve gradually approaches the historical batch curve. The adjusted values ​​during the correction process are recorded as correction values ​​and used to update the effective range of the corresponding historical batch strategy parameters in the process archive.

[0022] The technical solutions provided by the embodiments of this disclosure have at least the following beneficial effects: This invention utilizes the natural tracer properties of the decay chains of uranium / thorium nuclides in radioactive tailings. Based on the pre-calibration of homologous standard mineral samples, a mapping relationship between the activity ratio and the lattice defect density of rare earth minerals is established, enabling online non-destructive sensing of the reactivity of tailings minerals. Furthermore, the leaching process is dynamically controlled in stages according to the trend of activity ratio changes. After the selective preferential leaching of highly active minerals, the leaching of less active minerals is enhanced, thereby improving the total rare earth recovery rate while effectively suppressing the co-leaching of radioactive impurities such as uranium and thorium. Combined with the accumulation of process files and iterative correction of the mapping relationship, the system can adapt to batch drift of tailings mineralogical characteristics, reducing the process debugging cycle and operating costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the system framework structure of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Reference Figure 1 This application provides a system for the graded recycling of rare earth resources in radioactive tailings. The system mainly includes a gamma spectrometer, a leaching tank, a controller, a storage device, and an X-ray fluorescence analysis probe.

[0026] The gamma spectrometer is connected to the analog input port of the controller via a shielded signal cable. It is used to acquire the initial gamma spectrum information of the radioactive tailings and to monitor the activity ratio of characteristic gamma rays of the uranium or thorium series during the leaching process. The activity ratio refers to the ratio of the net count rates of two specified characteristic gamma rays in the uranium (or thorium) series.

[0027] The leaching tank is a closed reaction vessel with a jacketed heating structure and a stirring device, used to contain tailings slurry and perform leaching. The controller is connected to both the gamma-ray spectrometer and the leaching tank to execute the control logic described below. A storage device is connected to the controller to store process data.

[0028] Before the formal leaching, the controller receives the initial gamma spectrum information acquired by the gamma spectrometer and establishes an initial mapping relationship between the characteristic gamma-ray activity ratio of uranium-series or thorium-series minerals and the lattice defect density of each rare earth mineral based on this information.

[0029] It should be noted that the lattice defect density refers to the surface density or volume density of defect sites in the mineral crystal structure, which is determined by transmission electron microscopy or X-ray diffraction line width method, respectively.

[0030] The physical basis of the mapping relationship is as follows: In uranium- or thorium-series radioactive decay chains, the parent nucleus undergoes α or β decay to produce daughter nuclei. The migration and release behavior of these daughter nuclei within the mineral lattice is influenced by the adsorption and retention effects of lattice defect sites. Minerals with higher lattice defect densities exhibit enhanced trapping capabilities of internal dislocations, vacancies, and grain boundaries for decay daughter nuclei, leading to a reduced rate of release from the mineral grains and thus altering the temporal distribution of characteristic gamma-ray emission. Therefore, by measuring the activity ratio of specific energy characteristic gamma rays, the relative level of mineral lattice defect density can be inferred.

[0031] The method for establishing the initial mapping relationship is as follows: At least 5 to 10 sets of standard mineral samples, originating from the same source as the tailings to be treated but with significantly different lattice defect densities, are selected. The lattice defect densities of the standard mineral samples cover the density range of the tailings to be treated. For each set of standard mineral samples, the lattice defect density is determined using transmission electron microscopy or X-ray diffraction line width method, and the corresponding activity ratio is simultaneously measured using gamma-ray spectrometry under the same geometric conditions. Using the activity ratio as the independent variable and the lattice defect density as the dependent variable, a power function or nonlinear least squares method is used for fitting to obtain the mapping relationship. The coefficient of determination R² is not less than 0.85; if R² is less than 0.85, the number of standard mineral samples is increased or the form of the fitting function is changed until the requirement is met. In one embodiment, the mapping relationship is stored in a storage device in the form of a lookup table. The rows of the lookup table correspond to the activity ratio range, the columns correspond to the lattice defect density range, and the calibrated density values ​​are stored at the intersection of rows and columns.

[0032] Optionally, two characteristic peaks with energies of E1 (e.g., 92.6 keV, Th-234) and E2 (e.g., 351.9 keV, Pb-214) from uranium-series characteristic gamma rays, or two characteristic peaks with energies of E3 (e.g., 238.6 keV, Pb-212) and E4 (e.g., 583.2 keV, Tl-208) from thorium-series characteristic gamma rays, are selected, and the ratio of their net count rates is calculated as the activity ratio R.

[0033] Compared to traditional techniques that rely on offline sampling and laboratory analysis to determine the density of mineral lattice defects in tailings, the above method utilizes the natural tracer properties of radionuclide decay chains to invert the density distribution of reactive sites on the mineral surface in real time without disrupting the slurry system. This provides a direct mineralogical basis for subsequent staged leaching and significantly shortens the process response cycle.

[0034] During the leaching process, a gamma spectrometer monitors the tailings slurry in the leaching tank online at a preset sampling period (e.g., 5 to 30 seconds, preferably 10 seconds) to obtain the real-time activity ratio R. Based on the online monitoring value of the activity ratio, the controller controls the leaching strategy in stages: During the activity ratio increase phase (i.e., the activity ratio increases over time), it indicates that the target mineral with high reactivity (such as easily leached rare earth minerals with high lattice defect density) is preferentially leached. At this time, the controller implements a low-intensity leaching strategy to selectively leach the target mineral with high reactivity.

[0035] During the activity ratio decrease phase (i.e., the activity ratio decreases over time), it indicates that the easily leached minerals have been largely consumed, and the remaining target minerals have low reactivity. At this time, the controller implements a high-intensity leaching strategy to dissolve the target minerals with low reactivity.

[0036] The controller continuously calculates the rate of change of the activity ratio, i.e., the amount of change in the activity ratio per unit time. When the rate of change decreases from a positive value to below a preset threshold (e.g., the rate of change changes from positive to negative or approaches zero, where the preset threshold ranges from -0.005 to 0.005 per minute, preferably 0.001), it is determined that the leaching of the current target mineral is complete, triggering an adjustment of the leaching conditions or stopping the current stage of leaching. For example, if a low-intensity leaching strategy is currently being implemented, a switch to a high-intensity leaching strategy is triggered; if a high-intensity leaching strategy is currently being implemented, the termination of this stage of leaching is triggered.

[0037] Therefore, compared with a single leaching process with fixed parameters, the above-mentioned staged control strategy can dynamically adjust the leaching intensity according to the actual reactivity of the minerals, avoiding insufficient leaching of highly reactive minerals at low intensity, or excessive crushing of low-reactive minerals at high intensity leading to co-dissolution of impurities. Thus, while ensuring the rare earth recovery rate, it effectively suppresses the co-leaching of radioactive impurities such as uranium and thorium.

[0038] After each batch of leaching is completed, the controller records the initial gamma spectrum information, the activity ratio change sequence, and the leaching efficiency at each stage (e.g., measured by rare earth element leaching rate) to a storage device as a process file. Based on the process file, the initial mapping relationship is corrected to obtain the optimized mapping relationship.

[0039] Regarding the correction method: The correction operation is automatically executed after each batch of leaching. In the initial stage, the first correction is initiated after accumulating at least 3 batches of data; subsequent corrections are initiated for each new batch of data. The mapping coefficients are iteratively updated using recursive least squares, with the goal of minimizing the sum of squared residuals between the measured lattice defect density and the predicted value of the mapping relationship in a new batch. When the reduction in prediction deviation is no longer significant after 3 consecutive corrections (e.g., the change in residual standard deviation is less than 5%), the mapping relationship is considered to have converged, and subsequent batches use the current coefficients. When new data causes a significant increase in prediction deviation (e.g., the increase in residual standard deviation exceeds 10%), correction is retried.

[0040] Through the accumulation of process archives and iterative correction of mapping relationships, the system can adapt to the drift of mineralogical characteristics of tailings from different mining areas and with different storage years, solving the prediction deviation problem caused by the difference in the weathering and oxidation of tailings in the initial calibration model, and enabling the control strategy to gradually converge to the optimal as the amount of operating data increases.

[0041] In one embodiment, the low-intensity leaching strategy includes leaching agent concentration parameters and leaching duration parameters. A solids mass fraction detection device (e.g., a densitometer based on gamma-ray attenuation or ultrasonic echo principles) is installed in the leaching tank, and a controller acquires the real-time solids mass fraction of the slurry within the leaching tank.

[0042] When the solid mass fraction is higher than a first mass fraction threshold, the leaching agent concentration parameter is decreased; when the solid mass fraction is lower than a second mass fraction threshold, the leaching agent concentration parameter is increased. In one embodiment, the first mass fraction threshold ranges from 35wt% to 45wt%, preferably 40wt%; the second mass fraction threshold ranges from 15wt% to 25wt%, preferably 20wt%. Correspondingly, the concentration of the leachate is adjusted within the range of 0.5 mol / L to 3.0 mol / L, preferably 1.0 mol / L to 2.0 mol / L. Wherein, the third mass fraction threshold is greater than the first mass fraction threshold, and the first mass fraction threshold is greater than the second mass fraction threshold.

[0043] When the solid mass fraction is higher than the third mass fraction threshold, the leaching time parameter is extended. For example, the third mass fraction threshold ranges from 50wt% to 60wt%, preferably 55wt%; the baseline value for the leaching time can be set from 30 minutes to 120 minutes, preferably 60 minutes; the extension can be increased by 10% to 50% depending on the degree to which the solid mass fraction exceeds the third mass fraction threshold.

[0044] By adjusting the concentration and duration of the leaching agent based on the solid mass fraction, sufficient liquid-solid contact efficiency can be maintained under high solid content conditions, avoiding local mass transfer blockage caused by excessive slurry concentration; at the same time, it prevents reagent waste and subsequent neutralization burden caused by excessive leaching agent under low solid content conditions, thereby optimizing reagent consumption while ensuring leaching selectivity.

[0045] In another embodiment, the high-intensity leaching strategy includes heating rate parameters and stirring speed parameters. The leaching tank is equipped with a viscosity sensor (e.g., a rotary or vibratory online viscometer) and a bubble detection electrode. The controller acquires real-time viscosity data and bubble generation rate of the slurry within the leaching tank.

[0046] When the viscosity is higher than a first viscosity threshold, the stirring speed parameter is increased; when the viscosity is lower than a second viscosity threshold, the stirring speed parameter is decreased. In one embodiment, the first viscosity threshold ranges from 500 mPa·s to 1500 mPa·s, preferably 800 mPa·s; the second viscosity threshold ranges from 50 mPa·s to 300 mPa·s, preferably 150 mPa·s; and the stirring speed is adjusted from 100 rpm to 800 rpm, preferably 200 rpm to 500 rpm.

[0047] When the bubble generation rate exceeds the preset rate threshold, the heating rate parameter is reduced.

[0048] As an optional implementation, the preset rate threshold ranges from 5 to 20 bubbles per square centimeter per minute, preferably 10; the reference value for the heating rate ranges from 0.5°C to 3.0°C per minute, preferably 1.0°C to 2.0°C per minute. The bubble detection electrode detects the bubble generation rate by measuring the change in resistance between electrodes or the attenuation of ultrasonic echo.

[0049] By controlling the viscosity and stirring speed together, an effective solid-liquid suspension can be maintained in high-viscosity slurry, preventing rare earth mineral particles from settling and agglomerating. Combined with the limitation of the heating rate on the bubble generation rate, the violent acidolysis reaction and acid mist entrainment caused by local overheating can be avoided, thereby improving operational safety and reducing the dissolution of non-target minerals caused by violent reactions.

[0050] Furthermore, the controller acquires ambient temperature fluctuation data (e.g., measured by a thermocouple array arranged on the outer wall of the leaching tank) and humidity data (e.g., measured by a humidity sensor).

[0051] When the ambient temperature fluctuation exceeds a first fluctuation threshold and the humidity exceeds a preset humidity threshold, the heating belt anti-condensation protection is activated. In one embodiment, the first fluctuation threshold ranges from 3°C to 8°C, preferably 5°C; the preset humidity threshold ranges from 70%RH to 90%RH, preferably 80%RH. The heating belt is a silicone heating belt with a power density of 0.5W / cm² to 1.5W / cm², wrapped around the outer wall of the leaching tank and the pipe flange interfaces to prevent condensate from entering the electrical interfaces or causing localized corrosion of the tank.

[0052] Furthermore, the controller assesses the stability risk of the current leaching temperature control based on the amplitude of ambient temperature fluctuations. Preferably, the risk level index is defined as the ratio of the ambient temperature fluctuation amplitude to the reference temperature difference, where the reference temperature difference ranges from 5°C to 10°C, preferably 8°C. When the risk level is high (e.g., the ratio is greater than 1.0), the proportional gain of the heating system is reduced (e.g., reduced by 20% to 40% from the initial value); when the risk level is low (e.g., the ratio is less than or equal to 0.5), the proportional gain is increased (e.g., increased by 10% to 20% from the initial value) to improve the temperature response speed.

[0053] In semi-outdoor or industrial environments with significant temperature differences, condensation on the outer walls of leaching tanks and electrical interfaces is a common cause of equipment corrosion and measurement signal drift. By using heating belt protection triggered by ambient temperature and humidity and adaptive adjustment of proportional gain, condensation formation can be suppressed and the stability of the temperature control loop can be maintained without increasing additional temperature control energy consumption. This ensures the long-term reliable operation of precision measuring equipment such as gamma spectrometers under harsh conditions.

[0054] In another embodiment, before leaching begins, the controller acquires the initial gamma-ray spectrum and X-ray fluorescence spectrum information of the current batch of radioactive tailings. The net count rate of uranium-series or thorium-series characteristic peaks is extracted from the initial gamma-ray spectrum information as a first set of reference features; the characteristic X-ray fluorescence intensity of rare earth elements is extracted from the X-ray fluorescence spectrum information as a second set of reference features.

[0055] The first set of reference features and the second set of reference features are combined to form the comprehensive feature vector of the current batch. The controller queries the process archive in the storage device for the comprehensive feature vectors of historical batches with the same or similar tailings source as the current batch, and calculates the feature similarity. In one embodiment, when calculating the feature similarity, each component of the comprehensive feature vector is first normalized according to the maximum and minimum values ​​of that component in the historical batches, mapping it to the interval between 0 and 1; then the sum of squares of the differences between each component of the normalized vector and the historical vector is calculated; finally, a similarity value is mapped using a Gaussian kernel function, with a kernel width of 0.1 to 1.0, preferably 0.5. The closer the similarity value is to 1, the more similar the two batches are. When the similarity is higher than a preset matching threshold (e.g., a value range of 0.7 to 0.9, preferably 0.8), the historical batch is considered to be similar to the current batch.

[0056] Based on feature similarity, a preset threshold for the rate of change of activity ratio is matched and initialized from the process archive. Specifically, the average threshold of the several historical batches with the highest similarity (ranging from 3 to 10, preferably 5) is taken as the initial threshold for the current batch. The comprehensive feature vector, threshold value, and actual leaching effect of the current batch are recorded in the process archive for use in threshold initialization of subsequent batches.

[0057] Different batches of radioactive tailings exhibit significant differences in initial mineral composition and lattice defect distribution due to variations in their source ore layer, storage time, and degree of weathering. By comprehensively matching the similarity between feature vectors and historical process archives, a suitable leaching threshold for the current batch can be quickly initialized. This avoids the blindness of relying on trial and error based on human experience in traditional methods, significantly shortens the debugging cycle for new batches, and improves the success rate of the first leaching.

[0058] In another embodiment, during the leaching process, the controller acquires the redox potential (e.g., measured by a platinum electrode in conjunction with a reference electrode) and pH value (e.g., measured by an acid and alkali resistant glass electrode) of the slurry in the leaching tank, and combines the activity ratio, redox potential, and pH value into a three-dimensional state vector.

[0059] A pre-constructed standard curve library for leaching high-defect minerals is stored in the storage device. This library contains standard curves showing the change of the standard three-dimensional state vector over time under different mineral types and initial lattice defect densities. The construction method of the standard curve library is as follows: Standard mineral samples with calibrated lattice defect densities are selected, and leaching tests are conducted under controlled conditions. The changes in activity ratio, redox potential, and pH value over time are recorded simultaneously to obtain the three-dimensional state vector standard curve of the mineral sample under specific leaching parameters. The tests are repeated by changing the leaching parameters (leaching agent concentration, temperature, stirring speed) to establish a family of standard curves for the same mineral sample under different parameter combinations. The above process is repeated by changing the mineral sample type and lattice defect density level, ultimately forming a standard curve library covering the range of mineralogical characteristics of the target tailings. The standard curve library is stored in the storage device as a database, with each record containing the mineral sample source, lattice defect density, leaching parameter combination, and corresponding standard curve data.

[0060] The controller compares the three-dimensional state vector with a pre-built library of standard curves for leaching high-defect minerals in real time. During the comparison, the activity ratio, redox potential, and pH value are normalized according to their respective extreme values ​​in the historical standard curves. Then, the deviation between the three normalized components and their corresponding standard components is calculated, and the largest of the three deviations is taken as the overall deviation.

[0061] When the comparison result is higher than the first comparison threshold, the execution time of the current leaching stage is extended; when the comparison result is lower than the second comparison threshold, the current stage is terminated early and the next leaching stage is started. For example, the first comparison threshold ranges from 0.2 to 0.5, preferably 0.3; the second comparison threshold ranges from 0.05 to 0.15, preferably 0.1.

[0062] If the change in activity ratio is opposite to the change in redox potential and the deviation exceeds the preset allowable range, it indicates that an abnormal redox reaction may occur in the slurry system or that the measurement signal is interfered with. In this case, the controller suspends leaching and performs sampling verification. For example, the preset allowable range is from 0.1 to 0.3, preferably 0.2.

[0063] Relying solely on activity ratio as a criterion for leaching progress is susceptible to interference from statistical fluctuations in gamma spectroscopy measurements or variations in pulp density. By combining activity ratio, redox potential, and pH value into a three-dimensional state vector and comparing it with a standard curve library in multiple dimensions, cross-validation of the leaching process can be achieved, reducing the probability of misjudgment by a single sensor. Simultaneously, the detection of divergences between activity ratio and redox potential changes can promptly capture abnormal redox fluctuations in the pulp system, preventing rare earth losses and ineffective reagent consumption caused by continued leaching under unbalanced conditions.

[0064] Preferably, the controller continuously records the change in activity ratio over time and determines whether this change is accelerating or decelerating. Specifically, it calculates the change in activity ratio per unit time, i.e., the rate of change of the activity ratio. When the rate of increase in activity ratio begins to slow down continuously, i.e., the increase in activity ratio per unit time gradually decreases and turns into a negative increase (manifested as a continuous decrease in the rate of change of activity ratio and at least three consecutive negative values), the transition from a low-intensity leaching strategy to a high-intensity leaching strategy is initiated ahead of schedule.

[0065] During the transition process, the concentration of the leaching agent and the leaching temperature are gradually increased, with the increase rate set according to the rate of decrease in the activity ratio. In one embodiment, when the rate of decrease in the activity ratio is in the first decreasing range (e.g., 0.001 to 0.005 per minute), the concentration increase is a first concentration increment (e.g., 0.05 mol / L), and the temperature increase is a first temperature increment (e.g., 1°C per minute); when the rate of decrease is in the second decreasing range (e.g., greater than 0.005 per minute), the concentration increase is a second concentration increment (e.g., 0.10 mol / L), and the temperature increase is a second temperature increment (e.g., 2°C per minute). The above increments can be calculated based on the ratio of the tank volume to the standard volume (e.g., 2 cubic meters), where the actual increment equals the baseline increment multiplied by the square root of the ratio of the tank volume to the standard volume.

[0066] If the activity ratio continues to rise after the transition start and exceeds the predicted maximum by a certain range, it indicates that the transition judgment was premature. The controller will automatically extend the low-intensity leaching stage and store the activity ratio change record of this batch as a new feature in the process file. For example, the certain range is from 0.05 to 0.15, preferably 0.10.

[0067] Traditional staged leaching typically switches between stages based on fixed time intervals or fixed activity ratio thresholds, making it difficult to adapt to fluctuations in the content of easily leached minerals in different batches of tailings. By monitoring the acceleration of activity ratio changes to predict the transition timing, high-intensity leaching can be initiated in advance when easily leached minerals are about to be depleted but not completely depleted. This avoids the overall low processing efficiency caused by excessively long low-intensity stages and prevents the residue of easily leached minerals caused by premature switching, thus maintaining a high total rare earth recovery rate even when there are large fluctuations in mineral composition between batches.

[0068] In a preferred embodiment, the system further includes an X-ray fluorescence analysis probe, which is located outside the leaching tank and at the same position as the gamma spectrometer, for online monitoring of the X-ray fluorescence intensity of at least one characteristic rare earth element in the leachate.

[0069] Regarding the arrangement of the X-ray fluorescence analysis probe and the gamma spectrometer: Both are positioned on the same outer wall of the leaching tank, at a distance of 15cm to 30cm from the tank wall, preferably 20cm. A lead shielding partition with a thickness of 2mm to 5mm is installed between them to prevent high-energy gamma rays from the gamma spectrometer from interfering with the background of the X-ray fluorescence detector. The measuring optical axes of both probes are aligned with the same monitoring window of the leaching tank. This window is sealed with a thin film transparent to both X-rays and gamma rays, made of polyimide or Kapton, with a thickness of 25 to 50 micrometers. The X-ray fluorescence analysis probe is connected to the controller via optical fiber or coaxial cable.

[0070] The controller aligns the curves of X-ray fluorescence intensity and activity ratio on the time axis to calculate the relationship between the relative enrichment of each rare earth element and the activity ratio during the leaching process. Specifically, the relative enrichment is the ratio of the X-ray fluorescence intensity at the current moment to the X-ray fluorescence intensity at the initial moment. When the relative enrichment of a certain rare earth element reaches its peak during the activity ratio increase phase and then begins to decline, while the activity ratio is still increasing, a complexing agent is added to the leaching tank or the pH value is adjusted. In one embodiment, the complexing agent is EDTA or citric acid, with an addition concentration ranging from 0.01 mol / L to 0.1 mol / L, preferably 0.05 mol / L; the pH value is adjusted by increasing it by 0.2 to 0.5 units.

[0071] When the rate of change of activity ratio decreases below a preset minimum rate while the X-ray fluorescence intensity of the characteristic rare earth element is still rapidly increasing, leaching is preferentially determined based on the X-ray fluorescence intensity, and the preset minimum rate is automatically lowered. For example, the preset minimum rate ranges from -0.01 to 0.01 per minute, preferably 0.002; "still rapidly increasing" means that the X-ray fluorescence intensity continues to increase over time and maintains an increasing trend for at least 5 consecutive sampling cycles; the automatic reduction range is 30% to 50%.

[0072] The activity ratio reflects the equilibrium state of the radionuclide decay chain, and there may be a time lag or nonlinear deviation between it and the actual leaching progress of rare earth elements, especially when rare earth minerals undergo re-adsorption or co-precipitation. By introducing X-ray fluorescence intensity as a secondary criterion and aligning it with the activity ratio over time and cross-validating it, the loss of rare earth elements in the liquid phase can be detected in a timely manner before the activity ratio changes significantly. This allows for intervention by adding complexing agents or adjusting the pH value, improving the actual recovery rate of rare earth elements and avoiding false steady-state misjudgments caused by relying solely on the activity ratio criterion.

[0073] In another preferred embodiment, the controller compares the actual activity ratio change curve measured during the leaching process of the current batch with the standard change curve predicted by the initial mapping relationship established for that batch, and calculates the difference sequence between the two curves. Specifically, the difference sequence is the difference sequence obtained by subtracting the predicted activity ratio from the actual activity ratio.

[0074] When the fluctuation amplitude of the differential sequence remains within a preset stable range for multiple consecutive sampling periods, preparation for terminating leaching begins. For example, the multiple sampling periods range from 5 to 20, preferably 10; the preset stable range ranges from 0.02 to 0.08, preferably 0.05.

[0075] During the termination preparation phase, the autocorrelation degree of the differential sequence is calculated. When the autocorrelation degree changes from positive to negative and exceeds a preset limit, the high-intensity leaching strategy is stopped. For example, the autocorrelation coefficient is calculated for two adjacent sampling points with a sampling period of 10 seconds; the preset limit ranges from -0.3 to -0.1, preferably -0.2. The differential sequence characteristics at the time of termination are recorded in the process file to correct the expected change curve of the next batch of tailings from the same source.

[0076] Terminating leaching at a fixed duration or threshold often leads to over-leaching (increasing impurity dissolution and reagent consumption) or under-leaching (reducing rare earth recovery). By determining the termination timing through the fluctuation stability and autocorrelation characteristics of the differential sequence, high-intensity leaching can be precisely stopped when the system approaches steady state and shows signs of convergence. This ensures sufficient dissolution of difficult-to-leach minerals while avoiding the burden of subsequent separation and purification and the increase in radioactive waste liquid caused by over-leaching.

[0077] In another preferred embodiment, the controller merges the initial gamma spectrum data, the activity ratio variation curve, the leaching parameters used in each stage, and the final rare earth recovery rate of each batch of tailings into a single batch sample and stores it in the process archive. The leaching parameters used in each stage include the duration of low-intensity leaching, the timing of high-intensity leaching initiation, and the threshold values ​​used for switching between stages.

[0078] When the initial gamma spectrum of a new batch of tailings is more similar to the gamma spectrum of a historical batch in the process archive than a preset standard, the leaching strategy parameter sequence of that historical batch is directly used as the initial leaching scheme for the new batch. For example, the similarity is calculated using the full-spectrum correlation coefficient, and the preset standard ranges from 0.85 to 0.95, preferably 0.90.

[0079] During the leaching process of a new batch, the difference between the actual activity ratio change curve and the historical batch curve is compared in real time. When the accumulated difference exceeds the preset allowable range, online correction is initiated: using the historical batch curve as a target, the current leaching agent concentration and temperature are adjusted so that the actual activity ratio change curve gradually approaches the historical batch curve. Specifically, the controller has a built-in adjustment step lookup table, which uses the absolute value of the difference between the actual activity ratio and the corresponding historical value as an index to look up the corresponding concentration adjustment amount and temperature adjustment amount. For example, when the difference is in the range of 0.02 to 0.05, the concentration adjustment amount is 0.02 mol / L and the temperature adjustment amount is 0.2℃ per minute; when the difference is in the range of 0.05 to 0.10, the concentration adjustment amount is 0.05 mol / L and the temperature adjustment amount is 0.5℃ per minute; when the difference is greater than 0.10, the concentration adjustment amount is 0.10 mol / L and the temperature adjustment amount is 1.0℃ per minute. The aforementioned adjustment amount can be calculated based on the ratio of the tank volume to the standard volume (e.g., 2 cubic meters). The conversion relationship is that the actual adjustment amount equals the baseline adjustment amount multiplied by the square root of the ratio of the tank volume to the standard volume. For example, the preset allowable range is the cumulative difference between the actual curve and the historical curve, with a value range of 2.0 to 5.0, preferably 3.0. The adjusted values ​​during the correction process are recorded as correction amounts, used to update the valid range of the corresponding historical batch strategy parameters in the process archive.

[0080] For tailings from stable sources, their mineralogical characteristics exhibit a certain degree of batch continuity. By reusing and online correcting historical batch process files, historical experience can be transformed into quantifiable initial control parameters, reducing the trial-and-error costs of starting from scratch for each batch. Simultaneously, the cumulative updates of corrections enable the process file database to possess self-learning capabilities. As the number of batches processed increases, the system's control precision for similar tailings gradually improves, thereby achieving positive transfer and continuous optimization of process knowledge between batches.

[0081] It should be further explained that the method includes the following steps: S101: Initial calibration stage. The controller receives the initial gamma spectrum information acquired by the gamma spectrometer, establishes the initial mapping relationship between the activity ratio and the lattice defect density, and stores it in the storage device.

[0082] S102: Batch matching stage. The controller acquires the initial gamma-ray energy spectrum information and X-ray fluorescence spectrum information of the current batch of tailings, combines them into a comprehensive feature vector, performs similarity matching with historical batches in the process archive, and initializes the preset threshold for the activity ratio change rate.

[0083] S103: Low-intensity leaching stage. The controller executes a low-intensity leaching strategy, monitoring the activity ratio, solids mass fraction, redox potential, and pH value in real time. Based on the solids mass fraction feedback, the leaching agent concentration and duration are adjusted, and the stage execution duration is adjusted based on the comparison results between the three-dimensional state vector and the standard curve library.

[0084] S104: Transition Judgment Stage. The controller continuously calculates the rate and acceleration of change in activity ratio. When the rate of increase continues to slow down and turns into a negative increase, it is predicted that the highly active minerals are about to be exhausted, and the transition to a high-intensity leaching strategy is initiated. The concentration of leaching agent and temperature are increased in stages according to the rate of decrease in activity ratio.

[0085] S105: High-intensity leaching stage. The controller executes a high-intensity leaching strategy, monitors viscosity, bubble generation rate, and ambient temperature fluctuations in real time, adjusts the stirring speed based on viscosity feedback, limits the heating rate based on bubble rate, and activates anti-condensation protection and adaptive proportional gain adjustment based on ambient temperature and humidity.

[0086] S106: Termination determination stage. The controller compares the actual activity ratio change curve with the predicted standard curve point by point and calculates the difference sequence; when the fluctuation amplitude of the difference sequence remains stable for several consecutive sampling periods, and the autocorrelation degree changes from positive correlation to negative correlation exceeding the preset limit, the high-intensity leaching strategy is stopped.

[0087] S107: File Correction Phase. The controller merges the initial full-spectrum γ-ray energy spectrum data, the activity ratio variation curve throughout the process, the leaching parameters at each stage, and the final rare earth recovery rate of this batch into a batch sample and stores it in the process file database. The recursive least squares method is used to correct the initial mapping relationship and update the effective range of the historical batch strategy parameters.

[0088] The steps S101 to S107 described above constitute a complete leaching control closed loop.

[0089] In an optional verification embodiment, radioactive tailings from a uranium mine (uranium grade approximately 0.15%, total rare earth oxides approximately 2.8%) were used for leaching tests. Using the aforementioned system, after initial gamma-ray spectrum calibration and the establishment of a mapping relationship, a two-stage treatment process was performed: low-intensity leaching (dilute sulfuric acid concentration 1.2 mol / L, temperature 60°C, duration 45 minutes) and high-intensity leaching (dilute sulfuric acid concentration 2.5 mol / L, temperature 85°C, duration 60 minutes). The final rare earth leaching rate reached 92.3%, and the uranium co-leaching rate was controlled below 8.5%. After the process file was revised for this batch, when used for the next batch of tailings from the same source, the initial threshold matching error decreased from 15% to 4%, and the leaching efficiency improved by approximately 6%. Those skilled in the art will understand that the above verification data are merely examples, and actual process parameters need to be adaptively adjusted according to the specific mineral composition of the tailings; this application does not limit this.

[0090] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A graded recycling system for rare earth resources in radioactive tailings, characterized in that, include: A gamma spectrometer is used to obtain initial gamma spectrum information of radioactive tailings and to monitor the activity ratio of characteristic gamma rays of uranium-series or thorium-series uran ... Leaching tank, used to hold tailings slurry and perform leaching; The controller is connected to the gamma spectrometer and the leaching tank, respectively. A storage device, connected to the controller, is used to store process files; The controller is used for: Receive the initial gamma spectrum information acquired by the gamma spectrometer, and establish an initial mapping relationship between the characteristic gamma ray activity ratio of uranium series or thorium series and the lattice defect density of each rare earth mineral based on the information. The lattice defect density is the surface density or the volume density. During the leaching process, the activity ratio is received by the online monitoring of the γ-ray spectrometer. Based on the online monitoring value of the activity ratio, a low-intensity leaching strategy is controlled to selectively dissolve target minerals with high reactivity during the activity ratio rising phase, and a high-intensity leaching strategy is controlled to dissolve target minerals with low reactivity during the activity ratio falling phase. When the rate of change of the activity ratio decreases from a positive value to below a preset threshold, the leaching of the current target mineral is determined to be complete, triggering the adjustment of leaching conditions or stopping the leaching of the current stage. The initial γ-ray spectrum information, activity ratio change sequence, and leaching efficiency at each stage are recorded in the storage device as a process file. The initial mapping relationship is corrected based on the process file to obtain the optimized mapping relationship.

2. The graded recycling system for rare earth resources in radioactive tailings according to claim 1, characterized in that, The low-intensity leaching strategy includes leaching agent concentration parameters and leaching time parameters; the controller is also used for: Obtain the real-time solids mass fraction of the slurry in the leaching tank; When the solid mass fraction is higher than the first mass fraction threshold, the leachate concentration parameter is reduced; When the solid mass fraction is lower than the second mass fraction threshold, the leaching agent concentration parameter is increased; When the solid mass fraction is higher than the third mass fraction threshold, the leaching time parameter is extended.

3. A graded recycling system for rare earth resources in radioactive tailings according to claim 1, characterized in that, The high-intensity leaching strategy includes heating rate parameters and stirring speed parameters; the controller is also used for: Obtain real-time viscosity data and bubble generation rate of the slurry in the leaching tank; When the viscosity is higher than a first viscosity threshold, the stirring speed parameter is increased; when the viscosity is lower than a second viscosity threshold, the stirring speed parameter is decreased. When the bubble generation rate is higher than a preset rate threshold, the heating rate parameter is reduced.

4. A graded recycling system for rare earth resources in radioactive tailings according to claim 1, characterized in that, The controller is also used for: Acquire ambient temperature fluctuation data and humidity data outside the leaching tank; When the ambient temperature fluctuation exceeds the first fluctuation threshold and the humidity exceeds the preset humidity threshold, the heating belt anti-condensation protection is activated. Assess the stability risk of the current leaching temperature control based on the amplitude of ambient temperature fluctuations. If the risk level is high, reduce the proportional gain of the heating system; if the risk level is low, increase the proportional gain.

5. A graded recycling system for rare earth resources in radioactive tailings according to claim 1, characterized in that, The controller is also used for: The initial gamma-ray energy spectrum information and X-ray fluorescence spectrum information of the current batch of radioactive tailings are obtained. The net count rate of uranium-series or thorium-series characteristic peaks is extracted from the initial gamma-ray energy spectrum information as the first set of reference features, and the characteristic X-ray fluorescence intensity of rare earth elements is extracted from the X-ray fluorescence spectrum information as the second set of reference features. The first set of reference features and the second set of reference features are combined to form the comprehensive feature vector of the current batch. The comprehensive feature vectors of historical batches with the same or similar tailings source as the current batch are queried in the process archive of the storage device, and the feature similarity is calculated. Based on the feature similarity, a preset threshold for the rate of change of the activity ratio is matched and initialized from the process archive. The current batch's comprehensive feature vector, threshold value, and actual leaching effect are recorded in the process file for use in threshold initialization of subsequent batches.

6. A graded recycling system for rare earth resources in radioactive tailings according to claim 1, characterized in that, The controller is also used for: Obtain the redox potential and pH value of the slurry in the leaching tank, and combine the activity ratio, redox potential and pH value into a three-dimensional state vector; The three-dimensional state vector is compared in real time with a pre-constructed library of standard leaching curves for high-defect minerals. When the comparison result is higher than the first comparison threshold, the execution time of the current leaching stage is extended; when the comparison result is lower than the second comparison threshold, the current stage is terminated early and the next leaching stage is started. If the change in activity ratio is opposite to the change in redox potential and the deviation exceeds the preset allowable range, leaching will be suspended and sampling verification will be performed.

7. A graded recycling system for rare earth resources in radioactive tailings according to claim 1, characterized in that, The controller is also used for: Continuously record the change in activity ratio over time and determine whether the change is accelerating or decelerating. When the rate of increase of the activity ratio begins to slow down continuously, that is, when the increase of the activity ratio per unit time decreases and turns into a negative increase, the transition from the low-intensity leaching strategy to the high-intensity leaching strategy is initiated in advance. During the transition, the concentration of the leaching agent and the leaching temperature are gradually increased, with the rate of increase matching the current rate of decrease in activity ratio; If the activity ratio continues to rise after the transition start-up and exceeds the predicted maximum point by a certain range, the low-intensity leaching stage will be automatically extended, and the activity ratio change record of this batch will be stored as a new feature in the process file.

8. A graded recycling system for rare earth resources in radioactive tailings according to claim 1, characterized in that, It also includes an X-ray fluorescence analysis probe, which is located outside the leaching tank and at the same position as the gamma spectrometer, for online monitoring of the X-ray fluorescence intensity of at least one characteristic rare earth element in the leachate; The controller is also used for: Align the curves of X-ray fluorescence intensity and activity ratio on the time axis to calculate the relationship between the relative enrichment of each rare earth element during the leaching process and the change in activity ratio. When the relative enrichment of a rare earth element reaches its peak during the activity ratio increase phase and then begins to decline, while the activity ratio is still in the increase phase, add a complexing agent to the leaching tank or adjust the pH value. When the rate of change of activity ratio decreases below the preset minimum rate while the X-ray fluorescence intensity of characteristic rare earth elements is still increasing rapidly, leaching is preferentially determined based on the X-ray fluorescence intensity, and the preset minimum rate is automatically lowered.

9. A graded recycling system for rare earth resources in radioactive tailings according to claim 1, characterized in that, The controller is also used for: The activity ratio change curve actually measured during the leaching process of the current batch is compared point by point with the standard change curve predicted by the initial mapping relationship established for the batch, and the difference sequence between the two curves is calculated. When the fluctuation amplitude of the differential sequence remains within the preset stable range for multiple consecutive sampling periods, preparations are made to terminate the leaching process. During the termination preparation phase, the autocorrelation degree of the differential sequence is calculated. When the autocorrelation degree changes from positive to negative and the negative correlation degree exceeds a preset limit, the high-intensity leaching strategy is stopped. The differential sequence characteristics at the time of shutdown are recorded in the process file to correct the expected change curve of the next batch of tailings from the same source.

10. A graded recycling system for rare earth resources in radioactive tailings according to claim 1, characterized in that, The controller is also used for: The initial γ-ray energy spectrum data, the activity ratio variation curve throughout the process, the leaching parameters used in each stage, and the final rare earth recovery rate of each batch of tailings are combined into a batch sample and stored in the process archive. When the initial gamma spectrum of a new batch of tailings is more similar to the gamma spectrum of a historical batch in the process archive than the preset standard, the leaching strategy parameter sequence of the historical batch is directly used, including the duration of low-intensity leaching, the timing of high-intensity leaching start-up, and the thresholds used for switching each stage, as the initial leaching scheme for the new batch. During the leaching process of a new batch, the difference between the actual activity ratio change curve and the historical batch curve is compared in real time. When the difference accumulates to exceed the preset allowable range, online correction is initiated: with the historical batch curve as the target, the current leaching agent concentration and temperature are adjusted so that the actual activity ratio change curve gradually approaches the historical batch curve. The adjusted values ​​during the correction process are recorded as correction values, which are used to update the effective range of the corresponding historical batch strategy parameters in the process archive.

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