Hydrological parameter and electrochemical parameter coupling experiment method and device for uranium migration

Abstract

The invention discloses a hydrological parameter and electrochemical parameter coupling experiment device and method for uranium migration, and the method comprises the steps: constructing a fluid model containing a leaching solution and a uranium ore sample through a fluid circulation system; the multi-channel electrical measurement system and the hydrological sample acquisition system continuously acquire potential data and leaching liquid chemical parameters of the fluid model at different positions in the leaching liquid flowing direction according to a set sampling frequency; the resistivity and natural potential of the leaching solution in different sampling time periods are obtained through the collected chemical parameters and potential data of the leaching solution, the linear relation between the potential difference value of different sampling positions and the concentration change of the leaching solution is obtained through linear fitting, and the concentration change of the leaching solution is calculated by combining the coupling relation between the natural potential and the concentration and flow velocity of the leaching solution. And establishing a correlation model of the leaching solution polarizability and the uranium leaching rate, and predicting the uranium leaching rate of the uranium ore sample according to the correlation model. According to the method, accurate depiction of the leaching solution migration process and in-situ leaching uranium mining process parameter optimization are achieved, and the method has important theoretical value and engineering application prospects.

Description

Technical Field

[0001] This invention discloses an experimental method and apparatus for coupling hydrological and electrochemical parameters of uranium migration, which relates to experimental monitoring technology for uranium leaching mining processes. Background Technology

[0002] In-situ leaching mining of sandstone-type uranium deposits, as a green and efficient uranium mining technology, has become a major method for uranium resource supply in my country and even globally. In actual in-situ leaching mining of uranium deposits, the migration range, concentration distribution, and migration rate of the leaching solution directly determine the uranium leaching efficiency, resource recovery rate, and mining cost, and are core considerations for optimizing in-situ leaching uranium mining processes.

[0003] In existing in-situ leaching uranium mining technologies, monitoring of leaching fluid migration mainly relies on two types of methods: one is the traditional hydrogeochemical monitoring method, which involves deploying numerous monitoring wells around the mining area to collect groundwater samples and analyze parameters such as uranium concentration, pH value, and Eh value, combined with hydrodynamic simulations to infer the migration patterns of the leaching fluid. However, this method suffers from drawbacks such as sparse monitoring points, low spatiotemporal resolution, high cost, and inability to perform real-time dynamic monitoring, making it difficult to accurately depict the dynamic migration trajectory of the leaching fluid. The other type is the geophysical electrical method, which utilizes the electrical differences between the leaching fluid and the surrounding rock (such as resistivity and polarizability) to delineate the leaching fluid range. However, existing electrical monitoring methods do not fully consider the complex groundwater dynamics and hydrogeochemical processes during leaching fluid migration. The coupling influence mechanisms of groundwater flow, ion diffusion, and redox reactions on the total electric field are still unclear, resulting in monitoring accuracy that is difficult to meet the needs of practical engineering. The single in-situ leaching uranium mining monitoring method and the electrical detection method have the following shortcomings:

[0004] (1) Traditional in-situ leaching uranium mining monitoring methods have low spatiotemporal resolution and cannot dynamically depict the migration trajectory of the leaching solution in real time;

[0005] (2) Existing electrical resistivity tomography (EDT) monitoring does not take into account the multi-field coupling effect, resulting in insufficient monitoring accuracy;

[0006] (3) Indoor column immersion experiments lack the ability to simultaneously collect hydrological and electrical parameters, making it difficult to establish a quantitative correlation between the two;

[0007] (4) The lack of real-time data support for the optimization of uranium mining process parameters by in-situ leaching leads to resource waste and high costs.

[0008] In indoor experimental research, common in-situ uranium leaching column leaching experiments mainly involve measuring hydrological parameters such as uranium concentration, pH, and Eh to select oxidants and screen for optimal concentrations. For example, Chinese patent application CN112033863A discloses a device and method for measuring uranium migration in simulated soil using a small column. This method utilizes the penetration of uranium into the soil-rock medium of the model to form observable uranium content in the sampling gas within a PVC pipe at the upper end of the soil-rock medium, significantly shortening the original observation and experimental time. However, these experiments cannot capture the dynamic migration process of the leaching solution in real time. To ensure complete uranium leaching, excessive oxidants are usually added, resulting in resource waste and environmental pressure. Furthermore, existing column leaching experimental devices lack an integrated electrical parameter measurement module, making it impossible to simultaneously acquire hydrological and electrical parameters, hindering the establishment of a quantitative correlation between the two and limiting the application of electrical monitoring technology in field in-situ uranium leaching. Summary of the Invention

[0009] The technical problem solved by this invention is to provide a coupled experimental method and apparatus for uranium migration hydrological and electrochemical parameters, which is limited by the existing uranium ore in-situ leaching sampling experimental technology that can only sample and analyze hydrological and electrochemical parameters separately.

[0010] This invention is achieved using the following technical solution:

[0011] This invention first discloses an experimental apparatus for coupling hydrological and electrochemical parameters of uranium migration, comprising:

[0012] A fluid circulation system includes an experimental cylinder for containing uranium ore samples and leaching solution. The experimental cylinder has an inlet and an outlet at its two ends, and is connected to a filter tank via a conduit to form a circulation pipeline. A peristaltic pump for adjusting the flow rate of the leaching solution is installed on the conduit.

[0013] A multi-channel electrical measurement system includes a power supply, a power supply electrode, and a measuring electrode. The power supply is connected to both ends of the experimental cylinder through the power supply electrode to construct an external electric field for the leaching solution inside the experimental cylinder. The measuring electrode is arranged on the experimental cylinder along the flow direction of the leaching solution and is connected to a multi-channel data acquisition card to collect the potential data of the leaching solution at different locations inside the experimental cylinder.

[0014] The hydrological sample collection system includes several sampling ports arranged along the flow direction of the leaching solution on the experimental cylinder, and the sampling ports are closed by normally closed valves.

[0015] In a coupling experimental apparatus for hydrological and electrochemical parameters of uranium migration according to the present invention, the experimental cylinder is made of plexiglass, with flange structures at both ends for fixing, and an inlet and an outlet. The measuring electrodes are embedded equidistantly into the inner wall of the cylinder along the axial direction, and four sets of measuring electrodes are arranged circumferentially around the experimental cylinder at the same axial position.

[0016] In a coupled experimental apparatus for uranium migration hydrological and electrochemical parameters according to the present invention, the measuring electrode is an Ag / AgCl reference electrode, which is installed on the experimental cylinder by a threaded structure.

[0017] In a coupled experimental apparatus for uranium migration hydrological and electrochemical parameters according to the present invention, the sampling ports are further arranged equidistantly along the axial direction of the experimental cylinder on the inner wall of the cylinder and are kept normally closed by a tetrafluoroethylene valve.

[0018] In a coupling experimental apparatus for hydrological and electrochemical parameters of uranium migration according to the present invention, the power supply is a programmable voltage / current transmitter, and the power supply electrodes at both ends of the experimental cylinder are mesh titanium electrodes, which are respectively connected to the positive and negative electrodes of the programmable voltage / current transmitter.

[0019] The present invention also discloses a coupling experimental method for hydrological and electrochemical parameters of uranium migration. Using the coupling experimental device described above, a fluid model containing a leaching solution and a uranium ore sample is constructed through a fluid circulation system. A multi-channel electrical measurement system and a hydrological sample acquisition system continuously acquire potential data and chemical parameters of the leaching solution at different positions of the fluid model in the direction of leaching solution flow according to a set sampling frequency.

[0020] By collecting chemical parameters and potential data of the leaching solution, the resistivity and spontaneous potential of the leaching solution at different sampling time periods are obtained. The linear relationship between the potential difference at different sampling locations and the change in leaching solution concentration is obtained through linear fitting. Combined with the coupling relationship between spontaneous potential and leaching solution concentration and flow rate, a correlation model between leaching solution polarizability and uranium leaching rate is established, and the uranium leaching rate of uranium ore samples is predicted accordingly.

[0021] In a coupled experimental method for uranium migration using hydrological and electrochemical parameters according to the present invention, the fluid model further includes three experimental modes:

[0022] In the static mode without an external electric field, the leaching solution inside the experimental cylinder of the fluid circulation system remains static. The multi-channel electrical measurement system collects the static natural potential of the leaching solution, including only the static natural potential generated by the electrochemical effect of uranium migration within the leaching solution.

[0023] In the flow mode without an external electric field, the peristaltic pump of the fluid circulation system regulates the leaching solution in the experimental cylinder to a flowing state, and the multi-channel electrical measurement system collects the flow natural potential of the leaching solution, which includes electrochemical and electrokinetic effects.

[0024] In the external electric field-flow mode, the peristaltic pump of the fluid circulation system regulates the leaching solution in the experimental cylinder to a flowing state, and an external electric field is constructed at both ends of the experimental cylinder through the power supply. The multi-channel electrical measurement system collects the superimposed natural potential of the leaching solution, which includes electrochemical effect, electrokinetic effect, conduction current effect and current collection effect. Combining the potential data of the first two modes, the potential data corresponding to each effect is obtained by the difference method.

[0025] In the experimental method for coupling hydrological and electrochemical parameters of uranium migration according to the present invention, the linear relationship between the potential difference of the fluid model at different locations and the change in the concentration of the leaching solution is further as follows:

[0026] ,

[0027] Where C is the concentration of the leaching solution. The conductivity of the leaching solution is obtained by deriving the leaching solution potential at the corresponding location in the fluid model through the fundamental equations of the steady-state current field. , The calibration coefficients are determined by linear fitting using potential data and solution concentrations at different locations of the fluid model obtained from experiments.

[0028] In a coupled experimental method for uranium migration using hydrological and electrochemical parameters according to the present invention, the coupling relationship between the spontaneous potential and the concentration and flow rate of the leaching solution is further as follows:

[0029] ,

[0030] in, This represents the difference in natural potential at different locations within the fluid model. For the concentration gradient of the leaching solution at different locations in the fluid model, The flow rate of the leaching solution within the fluid model. The diffusion potential coefficient is... The electrokinetic potential coefficient is determined by linear fitting using potential data at different locations of the fluid model obtained experimentally and the concentration of the leaching solution.

[0031] In the experimental method for coupling hydrological and electrochemical parameters of uranium migration according to the present invention, the correlation model between the polarizability of the leaching solution and the uranium leaching rate is further as follows:

[0032] ,

[0033] in, The polarizability of the leaching solution after the experiment is completed. The uranium leaching rate of the leaching solution after the experiment is completed. V represents the volume of the leaching solution after the experiment, and m represents the mass of the uranium ore sample after the experiment. Let C be the initial mass fraction of uranium in the uranium ore sample, and C be the average concentration of the leaching solution. , The fitting coefficients are determined by fitting the measurement data obtained through experiments.

[0034] The present invention, by adopting the above technical solution, has the following beneficial effects:

[0035] The present invention has the following significant beneficial effects:

[0036] (1) Realize the synchronous acquisition of multiple field parameters. This invention innovatively integrates the fluid circulation, electrical monitoring and hydrological sample collection of uranium ore sample leaching solution, and realizes the real-time synchronous acquisition of flow field, electric field and concentration field parameters during the migration of leaching solution, which significantly improves the spatiotemporal resolution.

[0037] (2) Clarify the multi-field coupling mechanism. This invention separates the potential contribution of different effects through three fluid model experimental modes, establishes the coupling relationship, separates the potential contribution of current collection effect, electrokinetic effect and electrochemical effect through graded experiments, establishes a coupled ground electric field theoretical model, and clarifies the intrinsic relationship between hydrological parameters and electrical parameters of uranium migration process in leaching solution.

[0038] (3) Improve monitoring and optimization accuracy. Based on the quantitative coupling model of uranium ore samples, key parameters such as leaching solution concentration and uranium leaching rate can be quickly inverted through electrical parameters, providing real-time data support for the optimization of in-situ leaching uranium mining process parameters and reducing oxidant consumption and mining costs.

[0039] (4) The apparatus has strong stability and repeatability. The core components adopt a high-precision and corrosion-resistant design. The experimental parameters are controllable and adjustable, ensuring the reliability and repeatability of the experimental data.

[0040] (5) It has strong technical transferability, providing physical property calibration and theoretical support for electrical monitoring of uranium mining processes in the field, and can be widely applied to the monitoring and optimization of sandstone-type uranium mining.

[0041] In summary, the present invention provides an experimental apparatus and method for coupling hydrological and electrochemical parameters of uranium migration, which clarifies the multi-field coupling mechanism in the migration process of uranium ore leaching solution, establishes a quantitative coupling relationship between hydrological and electrochemical parameters, and realizes the accurate characterization of the leaching solution migration process and the optimization of in-situ leaching uranium mining process parameters. It is applicable to indoor experimental simulation, process parameter optimization, and field in-situ leaching process monitoring technology calibration for sandstone-type uranium ore mining.

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of an experimental setup for coupling hydrological and electrochemical parameters of uranium migration, as shown in the embodiment.

[0044] Figure 2 This is the front view of the experimental cylinder in the embodiment.

[0045] Figure 3 This is a top view of the cross-section of the experimental cylinder in the embodiment.

[0046] Figure 4a , 4b Figures 4c and 4c are schematic diagrams of the decomposition of coupled electric field effects under three experimental modes of the fluid model in this invention.

[0047] Figure 5a This is a schematic diagram illustrating the change of natural potential over time at different sampling ports of the experimental cylinder in the example.

[0048] Figure 5b This is a schematic diagram showing the change in the concentration of the leaching solution at the sampling port of the experimental cylinder over time, as illustrated in the example.

[0049] Figure 5c for Figure 5a and Figure 5b The diagram shows the correlation curve between the natural potential and the concentration of the leaching solution.

[0050] Figure 6 This is a three-dimensional schematic diagram illustrating the evolution of the potential isosurface of the fluid model over time in the embodiment.

[0051] Figure 7 This is a superimposed diagram of fluid velocity streamlines and potential distribution in the fluid model of the embodiment.

[0052] The numbers in the diagram are: 100-filtrate tank, 110-peristaltic pump, 120-inlet / outlet, 130-power supply electrode, 140-power supply, 150-conduit, 160-measuring electrode, 170-sampling port, 180-multi-channel data acquisition card, 190-experimental cylinder. Detailed Implementation

[0053] Example

[0054] See Figure 1The experimental apparatus for coupling hydrological and electrochemical parameters of uranium migration shown in the figure is a specific embodiment of the present invention. It includes a fluid circulation system, a multi-channel electrical measurement system, and a hydrological sample collection system. The fluid circulation system includes a filtrate tank 100, a peristaltic pump 110, and an experimental cylinder 190. The experimental cylinder 190 is a cylindrical body for containing uranium ore samples and leaching solutions. Inlet / outlet ports 120 are respectively provided at both ends of the cylinder. The two inlet / outlet ports 120 are connected to the filtrate tank 100 through a conduit 150 to form a circulation pipeline. The peristaltic pump 110 is provided on the conduit 150 to adjust the flow rate of the leaching solution in the experimental cylinder 190. The multi-channel electrical measurement system includes a power supply electrode 130, a power supply 140, a measuring electrode 160, and a multi-channel data acquisition card 180. The power supply 140 is connected to both ends of the experimental cylinder 190 through the power supply electrode 130 to construct an external electric field for the leaching solution inside the experimental cylinder. Multiple sets of measuring electrodes 160 are arranged on the experimental cylinder along the flow direction of the leaching solution, forming a measuring electrode array. The measuring electrodes 160 are connected to the multi-channel data acquisition card 180 to collect the potential data of the leaching solution at different locations inside the experimental cylinder. The hydrological sample collection system includes several sampling ports 170 arranged on the experimental cylinder along the flow velocity direction of the leaching solution. The sampling ports 170 are closed by normally closed valves.

[0055] See also Figure 2 and Figure 3 The experimental cylinder 190 is made of plexiglass, with flange structures at both ends for fixation, and includes an inlet and an outlet. The measuring electrodes 160 are equidistantly embedded in the inner wall of the cylinder along its axial direction, with four sets of electrodes 160 arranged circumferentially around the cylinder at the same axial position. The measuring electrodes 160 are Ag / AgCl reference electrodes, installed on the cylinder via a threaded structure. The sampling ports 170 are equidistantly arranged on the inner wall of the cylinder along its axial direction, and are normally closed via PTFE valves, used to collect leachate samples from different spatial locations within the cylinder. The power supply 140 is a programmable voltage / current transmitter, and the power supply electrodes 130 at both ends of the experimental cylinder 190 are mesh titanium electrodes, respectively connected to the positive and negative terminals of the programmable voltage / current transmitter.

[0056] Specifically, in this embodiment, the experimental cylinder 190 is made of polymethyl methacrylate (PMMA), with an inner diameter of 50 mm, an effective length of 500 mm, a wall thickness of 10 mm, a pressure resistance ≥ 0.6 MPa, and a light transmittance ≥ 92%. Both ends are sealed with flanges, and the sealing gaskets are made of fluororubber, resistant to acid and alkali corrosion. Electrode mounting holes and sampling ports are pre-drilled on the side walls, with a hole position accuracy of ±0.1 mm, ensuring spatial correspondence between the electrodes and sampling ports. The peristaltic pump 110 is a constant-flow peristaltic pump with a flow rate adjustment range of 0.1-10 mL / min and a flow rate accuracy ≤ ±1%. The conduit 150 is made of fluororubber, resistant to acid and alkali corrosion, with a continuous operating time ≥ 72 hours, and has a flow rate calibration function to achieve stable transport of the leaching solution.

[0057] The power supply 140 has a programmable DC transmitter with an input voltage of AC220V±10%, an output voltage that is continuously adjustable from 0-30V, and an output current of 0-1A. It supports the generation of arbitrary waveforms such as square waves, triangle waves, and sawtooth waves, with a waveform editing resolution of 1μs and an output stability of ≤±0.1%. It features overcurrent and overvoltage protection functions and an RS485 remote communication interface, enabling precise control of the applied electric field. The power supply electrode 130 has a diameter of 8cm, a mesh size of 1mm, a titanium purity of ≥99.5%, and is resistant to sulfuric acid concentrations of ≤5mol / L. It can withstand a maximum current density of ≥100mA / cm², achieving parallel and uniform power supply within the device and avoiding electric field distortion. The electrode leads are made of polytetrafluoroethylene insulated wire with a diameter of 1.5mm².

[0058] The measuring electrode 160 has a threaded structure with an inner diameter of 4mm and a thread specification of M5×0.8 on the rod. The exposed conductive area at the head is ≥0.5cm². Four rows of electrodes are evenly distributed around the circumference of the experimental cylinder 190, with an adjacent electrode spacing of 5cm. Each row has 7 electrodes arranged at equal intervals along the axial direction, forming a 4-column × 7-row distribution on the side wall of the experimental cylinder 190. The electrode potential drift is ≤0.1mV / h, and the internal resistance is ≤1kΩ, ensuring stable acquisition of the potential signal. The multi-channel data acquisition card 180 uses a 32-bit analog-to-digital converter, with ≥16 channels for simultaneous acquisition, a sampling rate ≥100kS / s, an input range of ±10V, and sampling noise ≤2μVrms. It supports USB 3.0 and Ethernet interfaces, and the data storage format is compatible with CSV and MATLAB. It is equipped with dedicated real-time plotting and data export software to achieve high-precision synchronous acquisition of electrical parameters.

[0059] The sampling ports 170 are spaced 10cm apart and have an inner diameter of 6mm. They are equipped with polytetrafluoroethylene valves, ensuring no leakage of the leaching solution and no interference with the flow field during the sampling process. The valve opening torque is ≤5N・m, ensuring the representativeness of the concentration sample.

[0060] The process of coupling hydrological and electrochemical parameters for uranium migration in this embodiment is as follows: A fluid model containing the leaching solution and uranium ore sample is constructed using a fluid circulation system. A multi-channel electrical measurement system and a hydrological sample acquisition system continuously collect potential data and chemical parameters of the leaching solution at different positions along the flow direction of the fluid model according to a set sampling frequency. The resistivity and spontaneous potential of the leaching solution at different sampling time periods are obtained by collecting the chemical parameters and potential data of the leaching solution. The linear relationship between the potential difference at different sampling positions and the change in the concentration of the leaching solution is obtained by linear fitting. Combined with the coupling relationship between the spontaneous potential and the concentration and flow rate of the leaching solution, a correlation model between the polarizability of the leaching solution and the uranium leaching rate is established, and the uranium leaching rate of the uranium ore sample is predicted accordingly.

[0061] The specific steps are as follows:

[0062] Step 1: Device Assembly and Sample Preparation. (Followed by...) Figure 1 The experimental apparatus was assembled with various system components. After crushing and grinding the uranium ore sample, uniform particles with a diameter of 0.5-1 mm were screened out and layered and compacted into the experimental cylinder 190, with the filling density controlled at 1.8-2.0 g / cm³.

[0063] Step 2: Initialize experimental parameters. Prepare the leaching solution of the designed concentration in the filtrate tank 100, set the flow rate of the peristaltic pump 110 to control the flow rate of the leaching solution, and set the external electric field parameters through the programmable voltage / current transmitter, including no external electric field or constant external electric field.

[0064] Step 3: Synchronous acquisition of multiple parameters. Turn on the peristaltic pump 110 to allow the leaching solution to migrate and flow within the experimental cylinder 190. The multi-channel data acquisition card 180 acquires the potential data of the measuring electrode 160 at a sampling frequency of not less than 10Hz. Samples of the leaching solution are collected through the sampling port 170 at preset time intervals.

[0065] Step 4: Measurement of hydrochemical parameters. Chemical parameters of the collected leachate samples were measured, including uranium concentration measured using ICP-MS, and pH and Eh values ​​measured using a pH meter and an Eh meter, respectively.

[0066] Step 5: Establishing the Coupling Relationship. The potential data is filtered, and electrical parameters such as resistivity, spontaneous potential, and polarizability are calculated. The potential contributions of current collection effect, electrokinetic effect, and electrochemical effect are separated through graded experiments. Combined with hydrological parameter data, a quantitative coupling relationship between the two is established through mathematical modeling.

[0067] Specifically, the fluid model of the leaching solution established inside the experimental cylinder 190 includes three experimental modes: static mode without external electric field, flow mode without external electric field, and flow mode with external electric field.

[0068] like Figure 4a As shown, in the static mode without an external electric field, the leaching solution inside the experimental cylinder 190 of the fluid circulation system remains static. The measuring electrode 160 of the multi-channel electrical measurement system collects the static natural potential of the leaching solution, which only includes the static natural potential generated by the electrochemical effect of free diffusion of uranium migration in the leaching solution, reflecting the potential change caused by the ion concentration gradient.

[0069] like Figure 4b As shown, in the flow mode without an external electric field, the peristaltic pump 110 of the fluid circulation system regulates the leaching liquid in the experimental cylinder 190 to a flow state. The multi-channel electrical measurement system collects the flow natural potential of the leaching liquid, which includes electrochemical and electrodynamic effects. The electrodynamic effect potential is separated by the difference between the flow natural potential data and the static natural potential data in the static mode without an external electric field.

[0070] like Figure 4c As shown, in the external electric field-flow mode, the peristaltic pump of the fluid circulation system regulates the leaching solution in the experimental cylinder to a flowing state, and an external electric field is constructed at both ends of the experimental cylinder through the power supply. The multi-channel electrical measurement system collects the superimposed natural potential of the leaching solution, which includes electrochemical effect, electrokinetic effect, conduction current effect and current collection effect. Combining the potential data of the first two modes, the potential data corresponding to each type of effect is obtained by the difference method.

[0071] In this embodiment, the uranium migration laboratory experiment simulating in-situ leaching of uranium includes the hydrodynamic circulation of the leaching solution and water, as well as hydrogeochemical processes such as oxidation-reduction, dissolution-precipitation, complexation-dissociation, and adsorption-desorption between the leaching solution and uranium ore. Under the excitation of an artificial current source, the total current density of the leaching solution fluid model inside the experimental cylinder is... From conduction current density Electrodynamic effect current density With electrochemical effect current density It consists of three parts, namely:

[0072] .

[0073] Among them, conduction current density It satisfies Ohm's law, that is:

[0074] .

[0075] in, The conductivity of the leaching solution. For electric field strength, The collected conduction electric field potential, It is the gradient operator. Represents the conduction electric field potential The spatial gradient describes the rate of change of potential in space and the direction of the fastest change.

[0076] The leaching solution contains a large number of charged chemical ions. When the leaching solution flows from the inlet to the outlet, the chemical ions in the leaching solution also flow along with it, which is called charge movement. According to the physical definition of electric current, when charges move in a certain direction, an electric current is generated, which is called the electrokinetic effect current density. ,Right now:

[0077] .

[0078] Where Q is the volume charge density of the leaching solution, located in the electric double layer between the sample solution and the medium. The flow rate of the leaching solution controlled by the peristaltic pump is calculated from the ratio of the peristaltic pump flow rate to the cross-sectional area of ​​the experimental cylinder.

[0079] The electrochemical effect refers to the migration of leached solutions under the influence of concentration gradients, hydrodynamic forces, and electric fields. The difference in migration rates between anions and cations leads to charge separation, generating a diffusion current density, which is the electrochemical effect current density. This effect can be represented by a chemical transfer equation, namely...

[0080] .

[0081] in, The pore water conductivity simulated in the leaching solution. The Hittorff number represents the fraction of current carried by cations or anions through a porous medium. is the Boltzmann constant, with a value of 1.381 × 10⁻⁶. -23 J / K, T is the leaching solution temperature, e is the electron charge, 1.602 × 10 -19 C.

[0082] Resistivity of the leaching solution containing uranium ore samples The formula is derived by measuring the voltage U and current I of the external electric field applied at both ends of the experimental cylinder and the geometric parameters of the experimental cylinder:

[0083] .

[0084] Where A is the cross-sectional area of ​​the experimental cylinder and L is the length of the leaching fluid between the measuring electrodes.

[0085] Samples of the leachate were collected at different times and locations through sampling ports, and parameters such as concentration, pH, and Eh were measured. Combined with the electrical parameter data from the above three modes, a quantitative coupling model of hydrological and electrical parameters of the leachate was established.

[0086] The linear relationship between the potential difference at different locations and the change in the concentration of the leaching solution in the fluid model is as follows:

[0087] .

[0088] Where C is the concentration of the leaching solution. The conductivity of the leaching solution is obtained by deriving the leaching solution potential at the corresponding location in the fluid model through the fundamental equations of the steady-state current field. , The calibration coefficients are determined by linear fitting using potential data and solution concentrations at different locations of the fluid model obtained from experiments.

[0089] The fundamental equation of a steady current field states that in a uniform conductive medium, when a constant external electric field is applied, the potential... Satisfies the Laplace equation:

[0090] .

[0091] in, For the Laplace operator.

[0092] The boundary condition is the current density constraint of the surface current source:

[0093] .

[0094] in, For dielectric conductivity, For current density, Let be the surface area of ​​the current source.

[0095] The coupling relationship between the spontaneous potential and the concentration and flow rate of the leaching solution is as follows:

[0096] .

[0097] in, This represents the difference in natural potential at different locations within the fluid model. For the concentration gradient of the leaching solution at different locations in the fluid model, The flow rate of the leaching solution within the fluid model. The diffusion potential coefficient is... The electrokinetic potential coefficient is determined by linear fitting using potential data at different locations of the fluid model obtained experimentally and the concentration of the leaching solution.

[0098] The correlation model between the polarizability of the leaching solution and the uranium leaching rate is as follows:

[0099] ,

[0100] in, The polarizability of the leaching solution after the experiment is completed. The uranium leaching rate of the leaching solution after the experiment is completed. V represents the volume of the leaching solution after the experiment, and m represents the mass of the uranium ore sample after the experiment. This represents the initial mass fraction of uranium in the uranium ore sample. , The fitting coefficients are determined by fitting the measurement data obtained through experiments.

[0101] The invention will be illustrated below through three specific experimental examples.

[0102] Case 1: Coupled observation experiment under no external electric field conditions.

[0103] 1. Sample preparation. A core sample of a sandstone-type uranium deposit was taken, crushed, and screened through a standard sieve to obtain particles with a diameter of 0.5-1 mm. These particles were then filled into the experimental cylinder 190, with a filling length of 40 cm and a filling density controlled at 1.9 g / cm³.

[0104] 2. Preparation of leaching solution. Prepare a leaching solution of 0.5 mol / L sulfuric acid + 0.05 mol / L hydrogen peroxide and pour it into a 100°C filter container.

[0105] 3. Experimental parameter settings. The flow rate of the peristaltic pump 110 was set to 2 mL / min, and the flow rate of the leaching solution was calculated. m / s, without applying an external electric field.

[0106] 4. Data Acquisition. Experimental data was continuously acquired for 10 hours. The multi-channel data acquisition card 180 acquired the potential data of the measuring electrode 160 at a sampling frequency of 10Hz. Every hour, the leaching solution sample was collected through the four sampling ports 170.

[0107] 5. Parameter Measurement. The uranium concentration in the leaching solution was measured using ICP-MS. Changes in the leaching solution concentration are shown below. Figure 5b As shown, a pH meter was used to measure pH values, ranging from 2.0 to 2.5, and an Eh meter was used to measure Eh values, ranging from 400 to 500 mV.

[0108] 6. Results Analysis. The spontaneous potential gradually increases over time, such as... Figure 5a As shown, the potential difference at the four sampling ports is significantly linearly correlated with the concentration of the leaching solution. The linear relationship between the potential difference and the change in the concentration of the leaching solution was obtained by fitting the data. Experimental calibration coefficient , ,like Figure 5c As shown, the coupling relationship between the natural potential and the concentration and flow rate of the leaching solution is obtained by fitting the data. diffusion potential coefficient Electrodynamic potential coefficient This verified the effectiveness of the quantitative coupling model.

[0109] Figure 6 The paper demonstrates the distribution of the electric potential isosurface within the leaching solution fluid in the experimental cylinder at times of 0h, 2.5h, 5h, 7.5h, and 10h. The high potential region gradually expands upward over time. Through the spatiotemporal dynamic evolution law of the electric potential field, the migration trajectory of the high potential region is consistent with the migration path of uranium ions, verifying the theory that "the electric potential field is a comprehensive characterization of the coupling effect of the flow field and concentration field," and supporting the spatiotemporal dynamic evolution theory of the coupled field in this invention.

[0110] Figure 7 The figure overlays the velocity streamlines (black arrows) and potential contour lines (colored curves) of the leaching solution in this case study, showing that the higher the flow velocity, the higher the potential. This figure, by illustrating the spatial coupling relationship between the flow field and the electric field, verifies the core theory that "the flow field regulates the electric field distribution by driving the migration of charged ions," supports the spatial coupling theory of flow field-electric field-concentration field of this invention, and clarifies the mechanism by which flow velocity affects potential distribution.

[0111] Case 2: Coupled observation experiment under the condition of an applied electric field.

[0112] 1. The parameters of the sample and the leaching solution are the same as in Example 1.

[0113] 2. Experimental parameter settings. The peristaltic pump 110 was maintained at a flow rate of 2 mL / min, the programmable voltage / current transmitter output voltage was 10V, the square wave frequency was 1Hz, and a constant external electric field was applied to both ends of the leaching fluid model inside the experimental cylinder.

[0114] 3. Data Acquisition. Potential data and hydrological parameters were acquired simultaneously over a period of 10 hours.

[0115] 4. Results Analysis. The resistivity decreases with increasing leaching solution concentration, consistent with the coupling relationship in this embodiment. The polarizability shows a logarithmic correlation with the uranium leaching rate. A correlation model between the polarizability of the leaching solution and the uranium leaching rate was obtained by fitting. Fit coefficient , It can quickly predict uranium leaching rate through polarizability, providing data support for optimizing in-situ leaching uranium mining process parameters.

[0116] Case 3: Field uranium leaching monitoring calibration experiment.

[0117] 1. Experimental preparation. A field sandstone-type uranium leaching area was selected, and core samples were collected. The experimental samples were prepared according to the method in Case 1.

[0118] 2. Experimental parameter settings. The simulated field leaching solution concentration was set to 0.3 mol / L sulfuric acid + 0.03 mol / L hydrogen peroxide. The flow rate of the peristaltic pump 110 was adjusted to 0.8 × 10⁻³ m / s. Experiments were conducted with and without an external electric field.

[0119] 3. Calibration Results. The quantitative coupling model established through indoor experiments was used to calibrate the electrical resistivity monitoring data of the field leaching mining area. The error in delineating the leaching solution range was ≤8%, and the error in predicting the uranium leaching rate was ≤5%, which significantly improved the accuracy of field leaching monitoring.

[0120] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0121] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0122] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. It should also be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0123] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An experimental apparatus for coupling hydrological and electrochemical parameters of uranium migration, characterized in that... include: A fluid circulation system includes an experimental cylinder for containing uranium ore samples and leaching solution. The experimental cylinder has an inlet and an outlet at its two ends, and is connected to a filter tank via a conduit to form a circulation pipeline. A peristaltic pump for adjusting the flow rate of the leaching solution is installed on the conduit. A multi-channel electrical measurement system includes a power supply, a power supply electrode, and a measuring electrode. The power supply is connected to both ends of the experimental cylinder through the power supply electrode to construct an external electric field for the leaching solution inside the experimental cylinder. The measuring electrode is arranged on the experimental cylinder along the flow direction of the leaching solution and is connected to a multi-channel data acquisition card to collect the potential data of the leaching solution at different locations inside the experimental cylinder. The hydrological sample collection system includes several sampling ports arranged along the flow direction of the leaching solution on the experimental cylinder, and the sampling ports are closed by normally closed valves.

2. The experimental apparatus for coupling hydrological and electrochemical parameters of uranium migration according to claim 1, characterized in that: The experimental cylinder is made of plexiglass, with flange structures at both ends for fixing, and an inlet and an outlet for water. The measuring electrodes are embedded equidistantly into the inner wall of the cylinder along the axial direction, and four sets of measuring electrodes are arranged circumferentially around the experimental cylinder at the same axial position.

3. The experimental apparatus for coupling hydrological and electrochemical parameters of uranium migration according to claim 2, characterized in that: The measuring electrode is an Ag / AgCl reference electrode, which is installed on the experimental cylinder through a threaded structure.

4. The experimental apparatus for coupling hydrological and electrochemical parameters of uranium migration according to claim 2, characterized in that: The sampling ports are equidistantly arranged along the axial direction of the experimental cylinder on the inner wall of the cylinder and are kept normally closed by a tetrafluoroethylene valve.

5. The experimental apparatus for coupling hydrological and electrochemical parameters of uranium migration according to claim 1, characterized in that: The power supply is a programmable voltage / current transmitter, and the power supply electrodes at both ends of the experimental cylinder are mesh titanium electrodes, which are respectively connected to the positive and negative terminals of the programmable voltage / current transmitter.

6. A coupled experimental method for uranium migration hydrological and electrochemical parameters, characterized in that: Using the coupled experimental apparatus of any one of claims 1-5, a fluid model containing a leaching solution and a uranium ore sample is constructed through a fluid circulation system. A multi-channel electrical measurement system and a hydrological sample acquisition system continuously acquire potential data and chemical parameters of the leaching solution at different positions of the fluid model in the direction of leaching solution flow according to a set sampling frequency. By collecting chemical parameters and potential data of the leaching solution, the resistivity and spontaneous potential of the leaching solution at different sampling time periods are obtained. The linear relationship between the potential difference at different sampling locations and the change in leaching solution concentration is obtained through linear fitting. Combined with the coupling relationship between spontaneous potential and leaching solution concentration and flow rate, a correlation model between leaching solution polarizability and uranium leaching rate is established, and the uranium leaching rate of uranium ore samples is predicted accordingly.

7. The experimental method for coupling hydrological and electrochemical parameters of uranium migration according to claim 1, characterized in that: The fluid model includes three experimental modes: In the static mode without an external electric field, the leaching solution inside the experimental cylinder of the fluid circulation system remains static. The multi-channel electrical measurement system collects the static natural potential of the leaching solution, including only the static natural potential generated by the electrochemical effect of uranium migration within the leaching solution. In the flow mode without an external electric field, the peristaltic pump of the fluid circulation system regulates the leaching solution in the experimental cylinder to a flowing state, and the multi-channel electrical measurement system collects the flow natural potential of the leaching solution, which includes electrochemical and electrokinetic effects. In the external electric field-flow mode, the peristaltic pump of the fluid circulation system regulates the leaching solution in the experimental cylinder to a flowing state, and an external electric field is constructed at both ends of the experimental cylinder through the power supply. The multi-channel electrical measurement system collects the superimposed natural potential of the leaching solution, which includes electrochemical effect, electrokinetic effect, conduction current effect and current collection effect. Combining the potential data of the first two modes, the potential data corresponding to each effect is obtained by the difference method.

8. The experimental method for coupling hydrological and electrochemical parameters of uranium migration according to claim 1, characterized in that: The linear relationship between the potential difference at different locations and the change in the concentration of the leaching solution in the fluid model is as follows: ， Where C is the concentration of the leaching solution. The conductivity of the leaching solution is obtained by deriving the leaching solution potential at the corresponding location in the fluid model through the fundamental equations of the steady-state current field. , The calibration coefficients are determined by linear fitting using potential data and solution concentrations at different locations of the fluid model obtained from experiments.

9. The experimental method for coupling hydrological and electrochemical parameters of uranium migration according to claim 1, characterized in that: The coupling relationship between the spontaneous potential and the concentration and flow rate of the leaching solution is as follows: ， in, This represents the difference in natural potential at different locations within the fluid model. For the concentration gradient of the leachate at different locations in the fluid model, The flow rate of the leaching solution within the fluid model. The diffusion potential coefficient is... The electrokinetic potential coefficient is determined by linear fitting using potential data at different locations of the fluid model obtained experimentally and the concentration of the leachate.

10. The experimental method for coupling hydrological and electrochemical parameters of uranium migration according to claim 1, characterized in that: The correlation model between the polarizability of the leaching solution and the uranium leaching rate is as follows: ， in, The polarizability of the leaching solution after the experiment is completed. The uranium leaching rate of the leaching solution after the experiment is completed. V represents the volume of the leaching solution after the experiment, and m represents the mass of the uranium ore sample after the experiment. Let C be the initial mass fraction of uranium in the uranium ore sample, and C be the average concentration of the leaching solution. , The fitting coefficients are determined by fitting the measurement data obtained through experiments.

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