A method for predicting the effect of in-situ leaching of sandstone-type uranium deposits after blasting

Abstract

The application discloses a kind of post-blasting sandstone type uranium mine in-situ leaching mining effect prediction method, it is related to sandstone type uranium mine in-situ leaching mining effect numerical simulation field, including: based on finite element analysis platform, HJC rock blasting constitutive model is constructed, blasting numerical simulation is carried out;Calibration is carried out to blasting fracture damage nephogram by Kriging interpolation algorithm;COMSOL multi-physics field model is constructed;Based on MATLAB, COMSOL multi-physics field model and the coupling interface of PHREEQC are constructed, and circulation time and time step are optimized;Geochemical reaction calculation is carried out and saved, while COMSOL file is run, the geochemical reaction calculation result is input into PHREEQC, and dynamic cyclic iteration simulation is obtained;Through integrated LSTM neural network, uraniumyl complex migration coefficient is dynamically corrected, and the output uranium migration multi-scale dynamic simulation result is obtained.Circulation termination.The application realizes the multi-scale dynamic simulation of uranium migration in the process of lixiviant injection, and improves the uranium migration prediction accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of numerical simulation of in-situ leaching of sandstone-type uranium deposits, in particular to a method for predicting the effect of in-situ leaching of sandstone-type uranium deposits after blasting. BACKGROUND

[0002] Sandstone-type uranium deposits are an important form of uranium resource worldwide, and their green and efficient development is a key link in the nuclear fuel cycle system. CO2+O2 in-situ leaching mining technology dissolves uranium ore bodies by injecting leaching solution and recovers uranium-containing solution, which has the advantages of high resource utilization rate and small environmental disturbance. However, traditional acid in-situ leaching has problems such as strong corrosion of leaching agent and high environmental risk, which restricts its sustainable development. The CO2+O2 neutral in-situ leaching technology has become a research hotspot in the field of uranium mining due to its wide dissolution range and environmental friendliness. However, the multi-field coupling-solute transport mechanism of CO2+O2 in-situ leaching of sandstone-type uranium deposits after blasting is complex and needs to be systematically studied.

[0003] Blasting, as a pretreatment process for uranium mining, produces a fracture network in the ore body through the release of explosive energy, changing the permeability and mechanical properties of the rock mass. However, the rock fragmentation, stress redistribution, and temperature field changes caused by blasting load form a coupling effect with the seepage field and chemical field after the injection of leaching agent, making it difficult for traditional single physical field simulation methods to accurately reveal the uranium migration rules. In addition, the CO2+O2 system involves complex multiphase chemical reactions (such as carbonate dissolution, uranium oxide oxidation-dissolution, etc.) during the leaching process, and the dynamic chemical equilibrium and spatiotemporal evolution characteristics of solute transport have a decisive influence on leaching efficiency and leaching agent optimization.

[0004] Current domestic and foreign scholars have conducted extensive research on the multi-field coupling problem of in-situ leaching, but the influence mechanism of blasting damage on the multi-scale pore structure of rock is still unclear, and there is a lack of relationship models between blasting parameters and energy evolution. The method for obtaining the kinetic parameters of multiphase chemical reactions in the CO2+O2 leaching system also has limitations, making it difficult to accurately describe the dynamic equilibrium process of mineral dissolution-precipitation, as well as to depict the collaborative evolution rules of macroscopic seepage field and microscopic pore structure. SUMMARY

[0005] The present application provides a method for predicting the effect of in-situ leaching of sandstone-type uranium deposits after blasting, which solves the problem of coupling simulation of commonly used software COMSOL and chemical software PHREEQC in the industry to simulate the multi-field coupling-solute transport of CO2+O2 in-situ leaching of sandstone-type uranium deposits, realizes multi-scale dynamic simulation of uranium migration, and simulation of multiple situations such as multi-physical field coupling and geochemical reactions under CO2+O2 in-situ leaching solute transport, and improves the prediction accuracy of uranium migration.

[0006] The application provides a blasting post-sandstone type uranium mine in-situ leaching mining effect prediction method, which comprises the following steps:

[0007] S1, based on a finite element analysis platform, an HJC (Holmquist-Johnson-Cook, a constitutive model for describing the mechanical behavior of rocks under impact and high pressure) rock blasting constitutive model is constructed, and then blasting numerical simulation is carried out to obtain a blasting crack damage cloud picture;

[0008] S2, according to the measured ground stress field data of the distributed optical fiber acoustic wave, the blasting crack damage cloud picture is calibrated through the Kriging interpolation algorithm to obtain a calibrated blasting crack damage cloud picture;

[0009] S3, according to the calibrated blasting crack damage cloud picture and COMSOL Multiphysics (a multi-physical field coupling simulation platform based on the finite element method, supporting modeling, simulation and optimization analysis of complex multi-disciplinary systems in engineering and scientific fields) software, an original COMSOL multi-physical field model is constructed, and the in-situ leaching liquid oxidation-reduction potential and pH value monitored by the electrochemical sensor are loaded into the original COMSOL multi-physical field model as boundary conditions to obtain a COMSOL multi-physical field model;

[0010] S4, based on the coupling interface of MATLAB (COMSOL (a multi-physical field coupling simulation platform based on the finite element method, supporting modeling, simulation and optimization analysis of complex multi-disciplinary systems in engineering and scientific fields) multi-physical field model and PHREEQC (a professional hydrogeochemical simulation software for studying the quantitative calculation and analysis of complex geochemical reactions, mineral dissolution and precipitation and multi-component ion balance in water solution system), the optimal time step in the seepage-dissolution coupling calculation stage in the circulation time is determined, and the optimal time step is input into the COMSOL multi-physical field model to obtain a COMSOL initial concentration;

[0011] S5, the COMSOL initial concentration is mapped to PHREEQC, and according to the equilibrium constraint condition of CO2+O2-water-rock reaction, MATLAB is used to call PHREEQC to perform geochemical reaction calculation to obtain a geochemical reaction calculation result;

[0012] S6, the geochemical reaction calculation result is saved, and the COMSOL file is run, and the geochemical reaction calculation result is re-input into PHREEQC as an initial value of the next time step to obtain a dynamic cycle iteration simulation;

[0013] S7, by integrating the parameter self-adaptive matching function driven by the LSTM neural network, the uranyl complex migration coefficient in the dynamic cycle iteration simulation process is dynamically corrected to obtain a corrected uranyl complex migration coefficient.

[0014] S8, repeating S4-S7 until the cycle time is reached and the calculation is terminated, outputting the uranium migration multi-scale dynamic simulation result.

[0015] Preferably, in S1, based on the finite element analysis platform, the HJC rock blasting constitutive model is constructed, and then the blasting numerical simulation is carried out, and the specific content of the blasting fracture damage cloud picture obtained includes:

[0016] In the finite element analysis platform, the HJC rock blasting constitutive model is constructed by defining the element material type and the model size; the element material type includes: rock, air and explosive;

[0017] The ground stress boundary condition, the rock dynamic compressive strength, the explosive JWL state equation and the air material attribute are defined;

[0018] The ground stress boundary condition is applied to the HJC rock blasting constitutive model, and the HJC rock blasting constitutive model is subjected to blasting numerical simulation according to the rock dynamic compressive strength, the explosive JWL state equation and the air material attribute, to obtain a blasting fracture damage cloud picture; the ground stress boundary condition includes: vertical constraint boundary and horizontal non-reflection boundary.

[0019] Preferably, in S2, the blasting fracture damage cloud picture is calibrated by the Kriging interpolation algorithm according to the ground stress field data measured by the distributed optical fiber acoustic sensor, and the calibrated blasting fracture damage cloud picture includes the following specific content:

[0020] Based on the ground stress field data measured by the distributed optical fiber acoustic sensor, the stress field spatial distribution characteristics are obtained, and the dynamic damage evolution input condition is established;

[0021] According to the stress field spatial distribution characteristics and the dynamic damage evolution input condition, the anisotropic deformation and crack propagation path of the damage region in the blasting fracture damage cloud picture are calibrated by using the Kriging interpolation algorithm, to obtain a regional damage two-dimensional correction model, and to obtain a calibrated blasting fracture damage cloud picture.

[0022] Preferably, in S3, the COMSOL multi-physics model is a coupled numerical model of porous medium rare substance transfer equation, Darcy seepage equation, mineral dissolution domain ordinary differential equation set and uranyl complex reaction diffusion equation.

[0023] Preferably, in S4, a coupling interface of the COMSOL multi-physics model and the PHREEQC is constructed based on MATLAB, the optimal time step in the seepage-dissolution coupled calculation stage in the cycle time is determined, and the optimal time step is input into the COMSOL multi-physics model to obtain the COMSOL initial concentration, which specifically includes:

[0024] A coupling interface of COMSOL multi-physics model and PHREEQC is constructed based on MATLAB;

[0025] The cycle time is optimized by leaching efficiency, and the optimized cycle time is obtained;

[0026] Based on the evolution characteristics of the uranium concentration gradient, a time step adaptive control algorithm is set, and the optimal time step in the seepage-dissolution coupling calculation stage in the optimized cycle time is obtained.

[0027] The optimal time step is input into the COMSOL multi-physics model to obtain the initial concentration of COMSOL.

[0028] Preferably, the calculation results of the geochemical reaction in S5 include: the data set of the concentration of the liquid phase elements in the pores and the precipitation amount of the secondary minerals.

[0029] Preferably, in S7, the parameter adaptive matching function driven by the LSTM neural network is integrated to dynamically correct the uranyl complex migration coefficient in the dynamic cycle iteration simulation process, and the corrected uranyl complex migration coefficient is obtained, which specifically includes:

[0030] The redox potential and pH value of the leaching solution monitored by the electrochemical sensor and the initial uranyl complex migration coefficient calculated by the COMSOL multi-physics model are input into the LSTM neural network for dynamic correction factor prediction, and the dynamic correction factor is obtained.

[0031] According to the dynamic correction factor, the parameter adaptive matching function driven by the LSTM neural network is integrated to automatically adjust the uranyl complex migration coefficient, and the corrected uranyl complex migration coefficient is obtained.

[0032] Preferably, the results of the uranium migration multi-scale dynamic simulation in S8 include: the data of the uranium concentration distribution and the prediction of the uranium migration path.

[0033] A post-blasting sandstone type uranium mine in-situ leaching exploitation effect prediction system, comprising:

[0034] The first model construction module is used to construct the HJC rock blasting constitutive model based on the finite element analysis platform, and then perform blasting numerical simulation to obtain a blasting fracture damage cloud picture;

[0035] The calibration module is used to calibrate the blasting fracture damage cloud picture by the Kriging interpolation algorithm according to the measured ground stress field data of the distributed optical fiber acoustic wave sensor, and obtain a calibrated blasting fracture damage cloud picture.

[0036] A second model construction module is configured to construct an original COMSOL multi-physical field model according to the calibrated blasting fracture damage cloud image and COMSOL Multiphysics software, and load the redox potential and pH value of the leaching solution monitored by the electrochemical sensor as a boundary condition into the original COMSOL multi-physical field model to obtain a COMSOL multi-physical field model.

[0037] A determination module is configured to construct a coupling interface of the COMSOL multi-physical field model and PHREEQC based on MATLAB, determine an optimal time step in a seepage-dissolution coupling calculation stage in a cycle time, and input the optimal time step into the COMSOL multi-physical field model to obtain a COMSOL initial concentration.

[0038] A calculation module is configured to map the COMSOL initial concentration to PHREEQC, and perform geochemical reaction calculation by calling PHREEQC by MATLAB according to a balance constraint condition of CO2+O2-water-rock reaction to obtain a geochemical reaction calculation result.

[0039] An iterative simulation module is configured to save the geochemical reaction calculation result, run a COMSOL file, and re-input the geochemical reaction calculation result into PHREEQC as an initial value of a next time step to obtain a dynamic cycle iterative simulation.

[0040] A correction module is configured to dynamically correct a uranyl complex migration coefficient in the dynamic cycle iterative simulation process by integrating a parameter self-adaptive matching function driven by an LSTM neural network to obtain a corrected uranyl complex migration coefficient.

[0041] An output module is configured to repeat the determination module, the calculation module, the iterative simulation module and the prediction module until the cycle time is reached and the calculation is terminated, and output a uranium migration multi-scale dynamic simulation result.

[0042] An electronic device, characterized in that it comprises a memory and a processor, the memory storing a computer program, and the processor calling the computer program in the memory to realize the content of the blasting post-sandstone type uranium mine in-situ leaching effect prediction method.

[0043] In summary, compared with the traditional technology, the blasting post-sandstone type uranium mine in-situ leaching effect prediction method has the following advantages:

[0044] (1) The present application solves the problem that it is difficult to couple the commonly used software COMSOL and the chemical software PHREEQC to simulate the multi-field coupling-solute transfer of the CO2+O2 in-situ leaching of the sandstone type uranium mine.

[0045] (2) The application establishes a seepage-stress-chemical coupling model of the blasting damaged rock mass by a COMSOL multi-physical field model, combines PHREEQC to calculate geochemical reaction, realizes multi-scale dynamic simulation of uranium migration in the injection process of leaching agent, and improves the prediction accuracy of uranium migration.

[0046] (3) The application realizes simulation of multiple situations such as multi-physical field coupling and geochemical reaction under the in-situ leaching of CO2+O2 solute migration based on the method of coupling COMSOL and PHREEQC based on MATLAB.

[0047] (4) The application has the advantages of small error and strong expansibility, greatly improves the applicability of the reactive solute migration model, and improves the possibility of COMSOL-PHREEQC secondary development.

[0048] The technical method of the application will be further described below by means of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 A flowchart of a blasting post-sandstone type uranium mine in-situ leaching mining effect prediction method provided for the embodiment of the application is shown in the figure.

[0050] Figure 2 A blasting permeability increase numerical simulation diagram under initial ground stress provided for the embodiment of the application is shown in the figure.

[0051] Figure 3 A solute migration model monitoring point diagram provided for the embodiment of the application is shown in the figure.

[0052] Figure 4 A monitoring point CaCO3 precipitation change diagram provided for the embodiment of the application is shown in the figure.

[0053] Figure 5 A 900-day uranium concentration in-situ leaching cloud diagram under COMSOL-PHREEQC coupling provided for the embodiment of the application is shown in the figure.

[0054] Figure 6 A uranium concentration change curve under COMSOL-PHREEQC coupling provided for the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0055] The technical method of the application will be further described below by means of the accompanying drawings and examples.

[0056] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting on the scope of the application or its applications or uses.

[0057] Techniques, systems, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered part of the specification where appropriate.

[0058] In all of the examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Thus, other examples of the example embodiments can have different values.

[0059] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0060] The application provides a blasting post-sandstone type uranium mine in-situ leaching mining effect prediction method, comprising the following steps:

[0061] S1, based on a finite element analysis platform, constructing an HJC rock blasting constitutive model, then performing blasting numerical simulation to obtain a blasting fracture damage cloud picture;

[0062] It can be understood that the finite element analysis platform can be an LS-DYNA finite element analysis platform, the HJC rock blasting constitutive model is constructed, an isotropic boundary condition of initial ground stress σx=σy=5MPa is given, a K file is written to define the dynamic compressive strength of rock, the JWL state equation of explosive and the material properties of air, the blasting numerical simulation under the ground stress condition is performed, and the blasting fracture damage cloud picture is obtained.

[0063] Further, the specific content of S1, based on the finite element analysis platform, constructing the HJC rock blasting constitutive model, then performing the blasting numerical simulation to obtain the blasting fracture damage cloud picture, comprises:

[0064] In the finite element analysis platform, the HJC rock blasting constitutive model is constructed by defining the element material type and the model size; the element material type comprises: rock, air and explosive;

[0065] The ground stress boundary condition, the dynamic compressive strength of rock, the JWL state equation of explosive and the material properties of air are defined;

[0066] The ground stress boundary condition is applied to the HJC rock blasting constitutive model, and the HJC rock blasting constitutive model is subjected to blasting numerical simulation according to the dynamic compressive strength of rock, the JWL state equation of explosive and the material properties of air, so as to obtain the blasting fracture damage cloud picture; the ground stress boundary condition comprises: vertical constraint boundary and transverse non-reflection boundary.

[0067] S2, according to the ground stress field data measured by the distributed optical fiber acoustic wave sensor, the blasting fracture damage cloud picture is calibrated by the Kriging interpolation algorithm to obtain a calibrated blasting fracture damage cloud picture;

[0068] Further, in S2, the blast fracture damage cloud is calibrated by Kriging interpolation algorithm according to the measured ground stress field data of the distributed optical fiber acoustic sensing, and the specific content of the calibrated blast fracture damage cloud includes:

[0069] Based on the measured ground stress field data of the distributed optical fiber acoustic sensing, the spatial distribution characteristics of the stress field are obtained, and the dynamic damage evolution input condition is established.

[0070] According to the spatial distribution characteristics of the stress field and the dynamic damage evolution input condition, the anisotropic deformation and crack propagation path of the damage area in the blast fracture damage cloud are calibrated by Kriging interpolation algorithm, a two-dimensional correction model of regional damage is obtained, and a calibrated blast fracture damage cloud is obtained.

[0071] S3, according to the calibrated blast fracture damage cloud and COMSOL Multiphysics software, an original COMSOL multi-physical field model is constructed, and the redox potential and pH value of the leaching solution monitored by the electrochemical sensor are loaded as boundary conditions into the original COMSOL multi-physical field model, and a COMSOL multi-physical field model is obtained.

[0072] It can be understood that the R2V format conversion plug-in is used to import the blast damage cloud output by LS-DYNA into COMSOL Multiphysics, a two-dimensional geological model with a length of 105m and a width of 70m is established, the Eh / pH dynamic boundary conditions of the real-time feedback of the downhole electrochemical sensor are embedded, the input settings of the material parameters and the multi-physical field model are completed, and the transient solver is configured.

[0073] Further, in S3, the COMSOL multi-physical field model is a coupled numerical model of porous medium rare substance transfer equation, Darcy seepage equation, mineral dissolution domain ordinary differential equation set and uranyl complex reaction diffusion equation.

[0074] S4, based on MATLAB, a coupling interface of COMSOL multi-physical field model and PHREEQC is constructed, the optimal time step in the seepage-dissolution coupled calculation stage in the cycle time is determined, and the optimal time step is input into the COMSOL multi-physical field model to obtain the COMSOL initial concentration.

[0075] Further, in S4, based on MATLAB, a coupling interface of COMSOL multi-physical field model and PHREEQC is constructed, the optimal time step in the seepage-dissolution coupled calculation stage in the cycle time is determined, and the optimal time step is input into the COMSOL multi-physical field model to obtain the COMSOL initial concentration, which specifically includes:

[0076] A coupling interface between COMSOL multi-physics model and PHREEQC is constructed based on MATLAB;

[0077] The leaching efficiency is used to optimize the cycle time, and the optimized cycle time is obtained;

[0078] Based on the evolution characteristics of uranium concentration gradient, a time step adaptive control algorithm is set to obtain the optimal time step in the seepage-dissolution coupling calculation stage within the optimized cycle time;

[0079] The optimal time step is input into the COMSOL multi-physics model to obtain the COMSOL initial concentration.

[0080] S5, mapping the COMSOL initial concentration to PHREEQC, and using MATLAB to call PHREEQC for geochemical reaction calculation according to the equilibrium constraint condition of CO2+O2-water-rock reaction, to obtain the geochemical reaction calculation result;

[0081] Further, the geochemical reaction calculation result in S5 includes the pore liquid element concentration and secondary mineral precipitation data set.

[0082] S6, save the geochemical reaction calculation result, run the COMSOL file, and re-input the geochemical reaction calculation result into PHREEQC as the initial value of the next time step, to obtain dynamic cycle iteration simulation;

[0083] S7, by integrating the parameter adaptive matching function driven by LSTM neural network, dynamically correcting the uranyl complex migration coefficient in the dynamic cycle iteration simulation process, to obtain the corrected uranyl complex migration coefficient;

[0084] Further, in S7, by integrating the parameter adaptive matching function driven by LSTM neural network, dynamically correcting the uranyl complex migration coefficient in the dynamic cycle iteration simulation process, to obtain the corrected uranyl complex migration coefficient, specifically including:

[0085] The redox potential and pH value of the leaching solution monitored by the electrochemical sensor and the initial uranyl complex migration coefficient calculated by the COMSOL multi-physics model are input into the LSTM neural network for dynamic correction factor prediction, to obtain the dynamic correction factor;

[0086] According to the dynamic correction factor, the parameter adaptive matching function driven by LSTM neural network is integrated to automatically adjust the uranyl complex migration coefficient, to obtain the corrected uranyl complex migration coefficient.

[0087] S8, repeat S4-S7 until the cycle time is reached and the calculation is terminated, and output the uranium migration multi-scale dynamic simulation result.

[0088] Further, the uranium migration multi-scale dynamic simulation result in S8 includes: uranium concentration distribution data and uranium migration path prediction.

[0089] Embodiments

[0090] The embodiment of the present application provides a CO2+O2 in-situ leaching mining effect prediction method for sandstone type uranium ore after blasting, which generates a blasting fracture damage cloud chart based on ANSYS / LS-DYNA, calibrates fracture network parameters by fusing DAS monitoring data and Kriging inversion model, develops a COMSOL-PHREEQC multi-physical field-chemical field coupling interface based on MATLAB, combines with field working condition information, constructs a blasting fracture network-seepage-chemical solute migration multi-scale coupling model, analyzes the regulation and control mechanism of CO2+O2-water-rock reaction on uranium ore dissolution and uranyl ion migration path under the condition of blasting damage, and reveals the evolution law of solute transfer under the dynamic coupling of stress field-seepage field-chemical field, such as Figure 1 as shown in the figure, and specifically as follows:

[0091] Step S1, based on ANSYS software or LS-DYNA software, a HJC rock blasting constitutive model (Hyperbolic Joint Constitutive, HJC) is constructed, that is, a two-dimensional blasting model, and meshing is performed, and then a vertical constraint boundary σ y and a horizontal non-reflective boundary σ x are defined, and the model is subjected to a ground stress boundary condition of σ x = σ y = 5MPa, the parameters in the k file are modified by using Visual StudioCode, and a blasting fracture damage cloud chart under ground stress is obtained.

[0092] Step S1 is specifically to define the unit material type in the LS-DYNA software "Preprocessor"→"Element Type / Material Props"→"Material Models", and select "3D Solid 164"; then define the size of the HJC rock blasting constitutive model in the "Modeling" module, and the size is 105m long, 70m wide. The air diameter is R 气 = 1m, and the blast hole radius is R 炮 = 0.1m; the rock, air and explosive are meshed respectively through "Meshing"→"Mesh Tool"; the initiation time is set as "Solution"→"Time Controls"→"Solution Time"→"25000" (initiation time: 25000us); and the ground stress is added "Keyword"→"DEFIND"→"CURVE" (σ x= σ y = 5 MPa), and save the files as "dy1.k" and "dy2.k", as shown in Figure 2 Delete the explosive and air material parameters in the "dy1.k" file, and then run the "dy1.k" file in "LS-Run"; generate a dynain initialization file with stress inheritance characteristics through dynamic compilation of the "dy1.k" file, and import it into the explosive and air model to make the rock mass in a state of action of the in-situ stress; run the "dy2.k" file in "LS-Run" to obtain the blasting damage cloud under the in-situ stress.

[0093] Step S2, fuse the measured in-situ stress field data of the distributed fiber acoustic sensing (DAS), calibrate the true shape of the blasting damage area through the Kriging interpolation algorithm, and obtain the calibrated blasting crack damage cloud.

[0094] Step S2 is specifically to capture the dynamic strain signal of the blasting stress wave (sampling frequency ≥ 10 kHz) in real time through the distributed fiber acoustic sensing, extract the frequency energy attenuation characteristics by combining denoising and Fourier transform to obtain the spatial distribution characteristics of the stress field; convert the stress field into a dynamic stress tensor by using the generalized Hooke's law, establish an anisotropic variogram model based on the Kriging interpolation algorithm, fuse the blasting crack damage cloud and the stress gradient extreme value data of the numerical simulation, dynamically correct the HJC rock blasting constitutive model parameters and the fracture network geometric parameters (connectivity error ≤ 8%) by using the Levenberg-Marquardt inversion algorithm, and cross-verify the spatial matching degree of the calibrated model (F1-score ≥ 0.85) through the microseismic monitoring data, finally realize the dynamic update of the permeability tensor matrix and the seepage-chemical coupling boundary conditions, and obtain the calibrated blasting crack damage cloud.

[0095] Step S3, use the R2V format conversion plug-in to import the calibrated blasting crack damage cloud into the COMSOL Multiphysics software, establish a two-dimensional geological model with a length of 105 m and a width of 70 m, i.e. the original COMSOL multi-physics field model, embed the dynamic boundary conditions of the leaching solution oxidation-reduction potential Eh and pH value fed back in real time by the downhole electrochemical sensor, obtain the COMSOL multi-physics field model, complete the input setting of the material parameters and the multi-physics field model, and configure the transient solver.

[0096] Step S3 is specifically opening the "R2V.exe" program, and selecting the calibrated blast fracture damage cloud under the ground stress; exporting the calibrated blast fracture damage cloud as a.dsf file through "image", "conversion" and "24-bit RGB, grayscale", and selecting "automatic vectorization" at the vector; opening the COMSOL software, importing the.dxf geometric fracture in the geometric component part and setting the well group model, establishing a coupled numerical model containing the porous medium rare substance transfer equation, Darcy seepage equation, mineral dissolution domain ordinary differential equation group and uranyl complex reaction diffusion equation, that is, the original COMSOL multi-physical field model; extracting the dynamic changes of Eh and pH monitored by the electrochemical sensor arranged in the underground tunnel of the uranium mine in real time (sampling interval ≤5 seconds), and capturing the chemical active signal of the solute transport process; the system loads the measured Eh and pH values of the sensor as boundary conditions into the original COMSOL multi-physical field model to obtain the COMSOL multi-physical field model.

[0097] When pH < 5.5, hexavalent uranium (U(VI)) exists in the form of uranyl ion UO2 2+ , which interacts with H + in water to promote the formation of complex ions, and the solubility of U(VI) increases sharply; a transient solver with a convergence tolerance ≤1e -5 is configured.

[0098] Step S4, based on MATLAB, a coupling interface of COMSOL-PHREEQC is constructed, 900 days of cycle days are set, and the optimal time step 100 days when COMSOL and PHREEQC are coupled for seepage-dissolution calculation is screened out. The specific code includes:

[0099] start_day = 0;

[0100] end_day = 900;

[0101] total_days = end_day - start_day;

[0102] dt_days = 100;

[0103] num_steps = total_days / dt_days;

[0104] phreeqc_exe = 'phreeqc.exe';

[0105] comsol_model = '3336.mph';

[0106] import com.comsol.model.

[0107] import com.comsol.model.util.

[0108] model = mphload(comsol_model).

[0109] Step S5, mapping the COMSOL initial concentration to PHREEQC.pqi file, and generating equilibrium constraint condition according to CO2+O2-water-rock reaction, using MATLAB to call PHREEQC to carry out geochemical reaction calculation, and obtaining geochemical reaction calculation result.

[0110] Step S5 is specifically to move the obtained COMSOL file to a path recognizable by MATLAB, and to call MATLAB to put the required concentration parameters into PHREEQC1.pqi file. The specific code includes:

[0111] x_coord = 52.9;

[0112] y_coord = 61.6;

[0113] O2_values = mphinterp(model, {'comp1.cO2'}, 'coord', [x_coord;

[0114] y_coord]);

[0115] O2_kgw = O2_values / 1000;

[0116] save('C:\Users\qifei\.comsol\v63\llmatlab\comsol_O2.mat','O2_kgw');

[0117] load('C:\Users\qifei\.comsol\v63\llmatlab\comsol_O2.mat',O2_kgw');

[0118] template = fileread('C:\Users\qifei\.comsol\v63\llmatlab\Phrqc1.pqi');

[0119] filled_template = strrep(template,'{O2}',num2str(O2_kgw(1),'%.4f'));

[0120] output_pqi = sprintf('C:\Users\qifei\.comsol\v63\llmatlab\Phrqc2.pqi');

[0121] fid = fopen(output_pqi, 'w');

[0122] fprintf(fid, '%s', filled_template);

[0123] fclose(fid);

[0124] disp('PHREEQC input file has been generated');

[0125] Based on the equilibrium constraint condition of CO2+O2-water-rock reaction, the dynamic dissolution-precipitation process of the simulated leaching solution with the initial temperature of 25℃ and the mineral was set; "monitoring point 1" and "monitoring point 2" were respectively set at the matrix and the fracture of the COMSOL multi-physical field model, as shown in Figure 3 ; then, the PHREEQC.pqi input file was called to run MATLAB to perform iterative calculation, and finally the mineral saturation index (SI) and ion concentration (Ca 2+ , SO4 2- , etc.) of the monitoring points were extracted.

[0126] In step S6, the obtained mineral and ion content were saved to a file, and the COMSOL file was run, and the obtained concentration was re-input into the PHREEQC file to replace the data, so as to prepare for the simulation of the next time step, and realize dynamic cyclic iterative simulation.

[0127] Step S6 is to extract Ca 2+ , Mg 2+ , CO3 2- and CaCO3 ion and precipitation concentration, and save them to files "Ca 2+ _tx", "Mg 2+ _txt", "CO3 2- _txt" and "CaCO3_txt", and draw the ion and precipitation change curve with time, as shown in Figure 4 . Figure 4 The CaCO3 precipitation concentration in the middle appears an initial stage, an acceleration stage and a stable stage, the initial stage is mainly an acidic environment, the pH value reverses in the acceleration stage, which promotes the reaction, and the ion concentration gradually becomes smaller, resulting in that the CaCO3 precipitation concentration gradually tends to be stable in the later stage.

[0128] When running the COMSOL file, assuming that the pore is in a fully saturated state, the relevant mathematical model and equation can be derived, and the seepage of the leaching solution in the ore bed pore can refer to Darcy's law:

[0129]

[0130] Where t is time, S is the water storage coefficient of the rock mass, P is the water pressure, u is the seepage velocity of the fluid in the matrix, e is the volumetric strain of the rock mass, Q is the source and sink term of seepage, k is the permeability of the porous medium, η is the dynamic viscosity of the fluid, ρ is the density of the fluid, is the water pressure gradient, g is the acceleration of gravity, is the height gradient.

[0131] Based on the convection-dispersion equation, a CO2+O2 in-situ leaching uranium model is constructed, which considers the adsorption and dispersion of solutes. The solute transport equation in COMSOL can be expressed as:

[0132]

[0133] Where θ is the liquid volume fraction, ρ b is the bulk density, k b is the adsorption isotherm, c i is the concentration of species i in the liquid, u1 is the node velocity obtained from the flow model, D is the diffusion coefficient, S i is the source term.

[0134] Based on the Ca 2+ , Mg 2+ and HCO3 - ion concentrations generated at the current time step, the script is used to batch modify the hydrochemical parameters of the PHREEQC input file (*.pqi), automatically replace the initial conditions through the code interface, save the updated results as the initial values for the next time step, and realize dynamic cyclic iteration simulation of multi-stage reactions.

[0135] Step S7, integrate the LSTM neural network driven parameter adaptive matching function, dynamically correct the uranyl complex migration coefficient, and obtain the corrected uranyl complex migration coefficient.

[0136] Step S7 is specifically based on historical simulation and measured data to construct a model containing pH, Eh, UO2 2+ ion concentration, CO3 2- ion concentration, Ca 2+Time series data sets of ion concentration and temperature and other characteristics; then, an LSTM neural network is used for modeling, inputting current water chemical parameters, and outputting predicted values of the uranyl complex migration coefficient (D_pred); in each iteration step of the PHREEQC simulation, the LSTM model is called in real time, the water chemical data obtained online are input into the model to predict D_pred, the migration parameters calculated by the traditional empirical formula are replaced after verification by sensitivity analysis, the numerical simulation conditions are dynamically updated through the PHREEQC interface, the multi-physical field coupling and solute transfer in the uranium migration process are optimized, and the corrected uranyl complex migration coefficient is obtained.

[0137] Step S8, the COMSOL-PREEQC coupling calculation process is circularly executed, the uranium ion concentration in the leaching solution is monitored in real time, the instantaneous uranium concentration at the current time node is calculated, and finally the uranium concentration cloud chart at the 900th day is obtained, as shown in Figure 5 The uranium concentration data obtained each time are automatically stored in time series, and finally the change curve of the uranium concentration with time is generated through a data visualization module, as shown in Figure 6 .

[0138] The method provided by the application for exploring the multi-field coupling-solute transfer mechanism and law of CO2+O2 in-situ leaching mining of sandstone type uranium mines after blasting is based on the ANSYS / LS-DYNA software to construct a blasting numerical model under ground stress, and the MATLAB is used to construct a coupling interface of COMSOL and PHREEQC, which is helpful to analyze the regulation mechanism of the CO2+O2-water-rock reaction on the uranium dissolution and the uranium ion migration path under the blasting damage condition, and the evolution law of the solute transfer under the dynamic coupling of the stress field-seepage field-chemical field, and has practical guiding significance.

[0139] The application provides a blasting in-situ leaching mining effect prediction system for sandstone type uranium mines, which comprises:

[0140] The first model construction module is used for constructing an HJC rock blasting constitutive model based on a finite element analysis platform, then performing blasting numerical simulation, and obtaining a blasting crack damage cloud chart.

[0141] The calibration module is used for calibrating the blasting crack damage cloud chart by a Kriging interpolation algorithm according to the ground stress field data measured by the distributed optical fiber acoustic wave sensor, and obtaining a calibrated blasting crack damage cloud chart.

[0142] The second model construction module is used for constructing an original COMSOL multi-physical field model according to the calibrated blasting crack damage cloud chart and the COMSOL Multiphysics software, and loading the oxidation-reduction potential and the pH value of the leaching solution monitored by the electrochemical sensor into the original COMSOL multi-physical field model as boundary conditions, so as to obtain the COMSOL multi-physical field model.

[0143] The determination module is used for determining the optimal time step in the seepage-dissolution coupling calculation stage in the cycle time based on the coupling interface of the MATLAB, the COMSOL multi-physical field model and the PHREEQC, and inputting the optimal time step into the COMSOL multi-physical field model to obtain the COMSOL initial concentration.

[0144] The calculation module is used for mapping the COMSOL initial concentration to the PHREEQC, and performing geochemical reaction calculation by calling the PHREEQC by the MATLAB according to the equilibrium constraint condition of the CO2+O2-water-rock reaction to obtain the geochemical reaction calculation result.

[0145] The iterative simulation module is used for saving the geochemical reaction calculation result, simultaneously running the COMSOL file, and re-inputting the geochemical reaction calculation result into the PHREEQC as the initial value of the next time step to obtain the dynamic cycle iterative simulation.

[0146] The correction module is used for dynamically correcting the uranyl complex migration coefficient in the dynamic cycle iterative simulation process by integrating the parameter self-adaptive matching function driven by the LSTM neural network to obtain the corrected uranyl complex migration coefficient.

[0147] The output module is used for repeating the determination module, the calculation module, the iterative simulation module and the prediction module until the cycle time is reached and the calculation is terminated to output the uranium migration multi-scale dynamic simulation result.

[0148] The application further provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor realizes the content of the blasting post-sandstone type uranium mine in-situ leaching mining effect prediction method when calling the computer program in the memory.

[0149] Finally, it should be noted that: the above examples are only used to illustrate the technical method of the application and not to limit it, although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: it can still modify or equivalently replace the technical method of the application, and these modifications or equivalent replacements also cannot make the modified technical method deviate from the spirit and scope of the technical method of the application.

Claims

1. A method for predicting the effect of in-situ leaching of a sandstone-type uranium deposit after blasting, characterized in that, The method comprises the following steps: S1, based on a finite element analysis platform, an HJC rock blasting constitutive model is constructed, and then blasting numerical simulation is performed to obtain a blasting fracture damage cloud image; S2, according to the measured in-situ stress field data of the distributed optical fiber acoustic sensor, the blasting fracture damage cloud image is calibrated through a Kriging interpolation algorithm to obtain a calibrated blasting fracture damage cloud image; S3, according to the calibrated blasting fracture damage cloud image and COMSOL Multiphysics software, an original COMSOL multi-physics field model is constructed, and the redox potential and the pH value of the lixivium monitored by the electrochemical sensor are loaded as boundary conditions into the original COMSOL multi-physics field model to obtain a COMSOL multi-physics field model; S4, a coupling interface of the COMSOL multi-physics field model and PHREEQC is constructed based on MATLAB, an optimal time step in a seepage-dissolution coupling calculation stage in a circulation time is determined, and the optimal time step is input into the COMSOL multi-physics field model to obtain a COMSOL initial concentration; S5, the COMSOL initial concentration is mapped to PHREEQC, and according to the equilibrium constraint condition of CO2+O2-water-rock reaction, MATLAB is used to call PHREEQC to perform geochemical reaction calculation to obtain a geochemical reaction calculation result; S6, the geochemical reaction calculation result is saved, a COMSOL file is run at the same time, and the geochemical reaction calculation result is re-input into PHREEQC as an initial value of a next time step to obtain a dynamic circulation iteration simulation; S7, by integrating a parameter self-adaptive matching function driven by an LSTM neural network, a uranyl complex migration coefficient in a dynamic circulation iteration simulation process is dynamically corrected to obtain a corrected uranyl complex migration coefficient; S8, S4-S7 are repeated until the circulation time is reached and the calculation is terminated, and a uranium migration multi-scale dynamic simulation result is output.

2. The method according to claim 1, characterized in that, In S1, the HJC rock blasting constitutive model is constructed based on the finite element analysis platform, and then blasting numerical simulation is performed to obtain the blasting fracture damage cloud image, and the specific content includes: In the finite element analysis platform, the HJC rock blasting constitutive model is constructed by defining the element material type and the model size; the element material type includes rock, air and explosive; The in-situ stress boundary condition, the rock dynamic compressive strength, the explosive JWL state equation and the air material attribute are defined; The in-situ stress boundary condition is applied to the HJC rock blasting constitutive model, and the rock dynamic compressive strength, the explosive JWL state equation and the air material attribute are used to perform blasting numerical simulation on the HJC rock blasting constitutive model to obtain the blasting fracture damage cloud image; the in-situ stress boundary condition includes a vertical constraint boundary and a horizontal non-reflection boundary.

3. The method according to claim 1, characterized in that, In S2, the blasting fracture damage cloud image is calibrated through the Kriging interpolation algorithm according to the measured in-situ stress field data of the distributed optical fiber acoustic sensor to obtain the calibrated blasting fracture damage cloud image, and the specific content includes: Based on the measured in-situ stress field data of the distributed optical fiber acoustic sensor, the stress field spatial distribution characteristics are obtained, and the dynamic damage evolution input condition is established; According to the stress field spatial distribution characteristics and dynamic damage evolution input conditions, the anisotropic deformation and crack propagation path of the damage area in the blasting fracture damage cloud picture are calibrated by using the Kriging interpolation algorithm, a two-dimensional correction model of regional damage is obtained, and a calibrated blasting fracture damage cloud picture is obtained.

4. The method according to claim 1, characterized in that, In S3, the COMSOL multi-physics model is a coupled numerical model of porous medium rare substance transfer equation, Darcy seepage equation, mineral dissolution domain ordinary differential equation set and uranyl complex reaction diffusion equation.

5. The method according to claim 1, characterized in that, In S4, a coupling interface of the COMSOL multi-physics model and PHREEQC is constructed based on MATLAB, the optimal time step in the seepage-dissolution coupling calculation stage in the cycle time is determined, and the optimal time step is input into the COMSOL multi-physics model to obtain the COMSOL initial concentration, which specifically includes: Constructing a coupling interface of the COMSOL multi-physics model and PHREEQC based on MATLAB; Optimizing the cycle time through leaching efficiency to obtain an optimized cycle time; Based on the evolution characteristics of the uranium concentration gradient, a time step self-adaptive control algorithm is set to obtain the optimal time step in the seepage-dissolution coupling calculation stage in the optimized cycle time; Input the optimal time step into the COMSOL multi-physics model to obtain the COMSOL initial concentration.

6. The method according to claim 1, characterized in that, In S5, the geochemical reaction calculation results include: pore liquid element concentration and secondary mineral precipitation data set.

7. The method according to claim 1, characterized in that, In S7, by integrating the parameter adaptive matching function driven by the LSTM neural network, the uranyl complex migration coefficient in the dynamic cycle iteration simulation process is dynamically corrected to obtain a corrected uranyl complex migration coefficient, which specifically includes: The redox potential and pH value of the leaching solution monitored by the electrochemical sensor and the initial uranyl complex migration coefficient calculated by the COMSOL multi-physics model are input into the LSTM neural network for dynamic correction factor prediction to obtain a dynamic correction factor; According to the dynamic correction factor, the uranyl migration coefficient is automatically adjusted by integrating the parameter adaptive matching function driven by the LSTM neural network to obtain the corrected uranyl complex migration coefficient.

8. The method according to claim 1, characterized in that, In S8, the uranium migration multi-scale dynamic simulation results include: uranium concentration distribution data and uranium migration path prediction.

9. A system for predicting the effect of in-situ leaching of a sandstone-type uranium deposit after blasting, characterised in that it comprises: It includes: The first model construction module is used to construct the HJC rock blasting constitutive model based on the finite element analysis platform, and then perform blasting numerical simulation to obtain a blasting fracture damage cloud picture; The calibration module is used to calibrate the blasting fracture damage cloud picture by Kriging interpolation algorithm according to the distributed optical fiber acoustic wave sensing measured ground stress field data to obtain a calibrated blasting fracture damage cloud picture; The second model construction module is used to construct an original COMSOL multi-physics model according to the calibrated blasting fracture damage cloud picture and COMSOL Multiphysics software, and load the redox potential and pH value of the leaching solution monitored by the electrochemical sensor as boundary conditions into the original COMSOL multi-physics model to obtain a COMSOL multi-physics model; The determining module is configured to determine an optimal time step in a seepage-dissolution coupling calculation stage in a cycle time based on a coupling interface of a COMSOL multi-physics field model constructed by MATLAB and PHREEQC, and input the optimal time step into the COMSOL multi-physics field model to obtain a COMSOL initial concentration; The calculating module is configured to map the COMSOL initial concentration to PHREEQC, and perform geochemical reaction calculation by calling PHREEQC through MATLAB according to a balance constraint condition of CO2+O2-water-rock reaction to obtain a geochemical reaction calculation result; The iterative simulation module is configured to save the geochemical reaction calculation result, run a COMSOL file, and re-input the geochemical reaction calculation result into PHREEQC as an initial value of a next time step to obtain a dynamic cycle iterative simulation; The correcting module is configured to dynamically correct a uranyl complex migration coefficient in the dynamic cycle iterative simulation process by integrating a parameter self-adaptive matching function driven by an LSTM neural network to obtain a corrected uranyl complex migration coefficient; The output module is configured to repeatedly determine, calculate, iteratively simulate and predict until the cycle time is reached and the calculation is terminated, and output a uranium migration multi-scale dynamic simulation result.

10. An electronic device, comprising: The device comprises a memory and a processor, the memory stores a computer program, and the processor calls the computer program in the memory to realize the content of the method for predicting the effect of sandstone-type uranium mining after blasting according to any one of claims 1 to 8.

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